Human caused climate change is changing the size and location of major climate zones, according to a new study.
Climate is complex, and a classic, widely used effort to wrangle that complexity into a sensible form is the Köppen classification system (and variants). We need not speak of the details here, but within this scheme there are five climate groups that include all of the possibilities for the Earth’s land surface. They are:
A: Tropical/megathermal climates
B: Dry (arid and semiarid) climates
C: Temperate/mesothermal climates
D: Continental/microthermal climates
E: Polar and alpine climates
This is sort of like a large scale version of the famous planting zone classification you use to determine when to plant your radishes or take in the last of the green tomatoes. The classifications are based on the idea that plants are indicators of the complex mix of factors that determine regional climate. Average temperatures matter, but high and low temperatures, when they occur (during the day and across the march of seasons) matter more, with key values such as frost mattering a lot. Average precipitation matters, but the distribution of precipitation across the year which might result in dry seasons matters a great deal. Ultimately, the local expression of global temperature, moisture, elevation, latitude, and the physical proximity to large bodies of water (most notably the oceans) and mountain ranges result in regional or local climate. The five classifications reflect zones that are mostly distributed across latitude (A on the Equator, E on the Poles) but that are also heavily influenced by altitude.
As humans add greenhouse gasses to the atmosphere the climate changes. We therefore expect these major classifications of regional climate to change as well, both in their relative sizes and in their locations with respect to latitude and altitude.
The paper is Open Access so you can go read it yourself. It is very clearly written and interesting. Here, I’ll just give you the key conclusions.
The research uses several data sources to conduct the analysis. All of the data are gridded across the globe, but some grids don’t have their own data because they are in remote areas with little or no instrumentation across the study period. Some data sets interpolate values into these grid squares, and those that do use different methods. One major data set leaves those grid squares blank and treats them as missing data. By using all of the data sets, the researchers were able to avoid coming up with results that were influenced by specific interpolation methods. Most importantly, though, they discovered that using the missing data approach did not change results because the missing data squares are mostly in the most A-like of Group A climate areas or the most E-like of Group E climate areas. Group A climate zones are growing, so being in the middle of those zones does not influence the analysis. So, not knowing what was going on in the middle of the Congo Raiforest does not change anything. Group E climate zones are shrinking, but those areas that are deep wihtin those zones (at the poles, on top of Mount Everest, etc.) don’t matter either.
Group D is “continental” and includes places like Chicago, Seoul, Salt Lake City, Ottawa, Flagstaff, and Faribanks. It is a very large zone that transits places that have real winters and those that have whimpier winters. Even though Group D is huge and significant, it also acts a bit like an ecotone or transition between Group C (Seasonally dry or arid, like Los Angeles, Cape Town, Beirut) and Group E (Tundra, ice caps, etc.). For this reason Group D is divided along the 55th parallel.
There are some complexities in how the data change over time which I will skip here (see the original paper). The point is, the zones do change significantly, with anthropogenic global warming being the primary cause. There is nothing particularly surprising in the results, but details can be important. Most importantly, the study also uses modeling to look at both past and future changes, and predicts an acceleration in change.
This graphic shows changes in climate types over the period 1950 to 2003 using one of the data sets (the data they chose for most of the analysis).
Linear trends in areas of 5 major climate types for 1950–2003
Tropical areas are expanding in space, moving north, and moving up in elevation. Not a lot, but a little. Why not a lot? The study does not say but I’ll guess. The tropical heat and moisture associated with this climate group are rapidly dispersed by air and water circulation systems and become part of the rest of the climate system quickly.
Arid and semi-arid areas (Group B) expand dramatically in area, and also move north and up hill. Why to they expand so much? There are probably two reasons. One is that more heat means more evaporation as well as more holding potential for water in the air. So ground moisture is sucked into the air at a greater rate, and stays there longer. Another (but closely related) reason may be the clumping of moisture we see in certain emerging weather patterns. Clumping means more arid conditions, even if that clumped water all falls eventually, on average, where it might have fallen anyway. A given amount of water falling uniformly in time and space across a region may provide a non-arid climate zone. The same amount of water falling non-uniformly in space, or especially, time, may result in a semi-arid zone.
Arid, semi-arid, subtropical Group B expands at the expense of Group C, while Group C is busy moving north but not up in elevation. The norther parts of Group D (ie, much of Canada) diminishes in area and moves north and uphill.
Group E, the cold bits, decline in area, move north, and retreat uphill.
The most important thing in this graphic is probably the expansion of Group B, where we can and do grow some food but under somewhat difficult conditions, and the loss of Group C area. The breadbasket, it is shrinking.
The paper concludes,
… major Köppen climate types since 1950 have occurred worldwide and are almost entirely attributed to the observed anthropogenic increase in greenhouse gas concentrations. Model runs project accelerating anthropogenic-induced major climate type changes in the next decades. As the Köppen climate classification links the Earth’s climates with the qualitative features of the vegetation, results here indicate that observed climate changes might already be causing significant impacts on vegetation in areas where the major climate class has changed, and model projections imply increasing future impacts.
Sunday, I had the honor of interviewing John Abraham about current developments in climate change. It was Sunday morning so you were probably either sleeping or in church, but don’t worry, there’s a podcast!
Here’s a partial list of other Atheist Talk interviews I’ve done, in case you were looking to spend several hours listening to me asking interesting people questions.
I don’t care that the director or CEO of an advocacy organization concerned with poverty is an active academic. Indeed, my view of active academics is that many are largely incompetent in areas of life other than their specialized field. If that. So really, if you told me there is this great advocacy organization out there run by a well established active academic I’d figure you had that wrong, or I’d worry a little about the organization. On the other hand, everyone should care that university positions be given to active academics with credentials. So, when the University of Western Australia got paid off (apparently) to give Bjørn Lomborg a faculty position everyone looked at the UWA and said, “WUT?”
That was a situation up with which the members of that university community would not put, to coin a phrase, and the public outcry put a quick end to it. This is appropriate, because according to a new post by Stefan Rahmstorf at RealClimate, “… apart from one paper in 1996, Lomborg has never published anything in any field of science that was interesting or useful to other scientists, or even just worth the bother of contradicting in the scientific literature.”
I’ve talked about Lomborg here before. Here I noted,
There is currently a twitter argument happening, along with a bit of a blogging swarm, over a chimera of a remark made by John Stossle and Bjorn Lomborg. They made the claim that a million electric cars would have no benefit with resect to Carbon emissions. The crux of the argument is that there is a Carbon cost to manufacturing and running electric cars. When we manufacture anything, we emit Carbon, and when we make electricity to run the cars, we emit Carbon, etc. etc.
Lomborg is wrong, wrong, wrong, wrong, wrong. But here I want to focus on one aspect of why he is wrong that applies generally to this sort of topic….
Stefan’s post looks in detail at two things (and in less detail at many other things). First, is the question of whether or not Lomborg is an actual practicing academic with a good publication record and all that. He is not. Stefan’s analysis is clear.
Second, is a more detailed look at Lomborg, sea level rise, Bangladesh, and all that. This is especially interesting because Stefan is one of the world’s leading experts on sea level rise. He has two peer reviewed papers on the “top ten most cited” on the Web of Science (which has well ove 40,000 sea level rise related papers), which are heavily cited. Stefan’s post is a must-read because of Stefan’s overview of sea level rise, aside from the stuff about Lomborg. Go read it.
So go read the post, learn about Bjørn Lomborg’s academic qualifications, how wrong he has been about sea level rise, and some other good stuff.
I suspect we are not going to see much more about Bjørn going forward.
Meanwhile, wildfires out west are really bad. A friend of mine drove way into the rocky mountains over the last few days and noted that for a long time he couldn’t even see any mountains the smoke was so bad. I suppose we’re lucky here in Minnesota. We get a LOT of smoke from fires in the Canadian Rockies and Alaska, but now most of the smoke is passing to our south.
Anyway, there are now tens of thousands of people fighting the fires, including many brought in from other regions, and even other countries. At the moment there are no fire fighters left. If you live out there in the chaparral and a fire starts near your house, you might not be able to get help. Check it out.
A quick update on sea ice melt. This time I decided to display, on a graph produced using the interactive tool made available by the NSIDC, the first 20 years for which there are data (to get the background) and the current year so far, of Arctic Sea ice extent:
The meme at the top of the post is available in higher resolution HERE if you want.
A new paper examines what is behind the ~2% of climate change related peer reviewed research that run contrary to widely accepted scientific consensus on climate change to see why those papers are wrong.
There is a scientific consensus that increasing greenhouse gas concentration in the atmosphere causes surface warming, and that CO2 is a major greenhouse gas. This consensus is based on physics. We don’t need to observe the effects of human greenhouse gas pollution to know this. There is consensus that human burning of fossil fuel causes an increase in CO2 in the atmosphere. We don’t need to observe this to know it, because we know how combustion works. But it is relatively simple to measure, and it has been measured, and it is true. There is consensus that the planet’s surface has warmed. This is expected from the physics and the fact that we are increasing atmospheric CO2, but it is also relatively easy to measure, it is measured, and it is true. There are varying levels of understanding the effects of this process, and varying degrees to which the effects of surface warming are thought to cause specific effects. One could probably characterize the scientific consensus as a widespread understanding that surface warming has had and will have a range of effects, with many of those effects being changes in weather patterns or regional climatology (how warm/cool/dry/wet a region generally is across he seasons) arising from a combination of “natural variability” (what would happen without greenhouse gas pollution) and anthropogenic global warming.
It is interesting, then, to see the results of various studies of scientific consensus related to climate change. Two kinds of studies have been done. One asks scientists what they think, the other reviews the scientific literature to see what the peer reviewed papers that address climate change say. In both cases we see a number between 90 (or, really, 95) and 100 percent agreement on the stuff in the paragraph above. It is not surprising that the vast majority of scientists, and the vast majority of research papers, have very similar things to say about climate change. This is not new science, and while climate is very complex, the basics of anthropogenic global warming are well understood. The results of empirical research closely match expectations derived from the physics. It all hangs together pretty well.
What is surprising is to see that 3-6% or so disagreement. Who are those scientists, why do they disagree, what do those papers say?
I would assume that since consensus research takes time, and often looks at several years worth of papers, that some of that non-consensus reflects older thinking and older research. Also, there are climate contrarians, including some scientists, who oppose the consensus for reasons not based on the science. That sort of denial presumably comes from the simple fact that some corporations or wealthy individuals will see reduced profits as we make the inevitable shift away from fossil fuels. So some of that non-consensus may be bought and paid for self interested maneuvering.
Rasmus Benestad, Dana Nuccitelli, Stephan Lewandowsky, Katherine Hayhoe, Hans Olav Hygen, Rob van Dorland, and John Cook, in “Learning from mistakes in climate research” (Theoretical and Applied Climatology) looks at the non-consensus peer reviewed literature.
The paper is here, and author Dana Nuccitelli has a writeup on the paper here. From the abstract:
Among papers stating a position on anthropogenic global warming (AGW), 97 % endorse AGW. What is happening with the 2 % of papers that reject AGW? We examine a selection of papers rejecting AGW. An analytical tool has been developed to replicate and test the results and methods used in these studies; our replication reveals a number of methodological flaws, and a pattern of common mistakes emerges that is not visible when looking at single isolated cases. Thus, real-life scientific disputes in some cases can be resolved, and we can learn from mistakes. A common denominator seems to be missing contextual information or ignoring information that does not fit the conclusions, be it other relevant work or related geophysical data. In many cases, shortcomings are due to insufficient model evaluation, leading to results that are not universally valid but rather are an artifact of a particular experimental setup. Other typical weaknesses include false dichotomies, inappropriate statistical methods, or basing conclusions on misconceived or incomplete physics. We also argue that science is never settled and that both mainstream and contrarian papers must be subject to sustained scrutiny. The merit of replication is highlighted and we discuss how the quality of the scientific literature may benefit from
replication.
The researchers found that cherry picking was the most common explanation for the non-consensus papers contrary results. In other words, it is not the case that a small number of paper simply found the physics, or some other aspect of, global warming to be different than other researchers found, or that they were looking at a part of the system that acts differently. Rather, these papers were wrong, and for a specific reason.
We found that many contrarian research papers omitted important contextual information or ignored key data that did not fit the research conclusions. For example, in the discussion of a 2011 paper by Humlum et al. in our supplementary material, we note,
The core of the analysis carried out by [Humlum et al.] involved wavelet-based curve-fitting, with a vague idea that the moon and solar cycles somehow can affect the Earth’s climate. The most severe problem with the paper, however, was that it had discarded a large fraction of data for the Holocene which did not fit their claims.
The authors attempted a replication of that particular research, and found that the model they used only worked for part of the underlying data. The data that were ignored by Humlum et al contradicted their findings.
Another problem identified by Benestad et al is the lack of a consistent sensible alternative explanation for their alleged findings. “…there is no cohesive, consistent alternative theory to human-caused global warming. Some blame global warming on the sun, others on orbital cycles of other planets, others on ocean cycles, and so on. There is a 97% expert consensus on a cohesive theory that’s overwhelmingly supported by the scientific evidence, but the 2–3% of papers that reject that consensus are all over the map, even contradicting each other.”
We need to act urgently to reduce the amount of greenhouse gas pollution we humans create in order to slow down and eventually stop climate change. In the mean time we see case after case of something happening that seems unusual and that seems linked to global warming. We need not wait for the jury to return a verdict in every single case in order to act. We already know what many of the effects of climate change are, and we have a reasonably good idea of what effects will arise in the future. Even so, every now and then something happens that any reasonable person might guess is linked ultimately to greenhouse gas pollution, and we should pay attention to those cases.
Whales die, and sometimes their bodies wash up on shore. Over the last few months, the rate at which this happens seems to have increased about 300% in the Gulf of Alaska and maybe in other areas as well. One possible culprit is warming of northern waters (you may have heard of the Warm Blob), which in turn feeds the development of toxic microbes. Warming can also have other effects as well. This set of effects is thought to be a possible, maybe likely, cause of this alarming rate of whale deaths. Many of the whales are larger species.
From NOAA:
Since May 2015, 11 fin whales, 14 humpback whales, one gray whale, and four unidentified cetaceans have stranded around the islands of the western Gulf of Alaska and the southern shoreline of the Alaska Peninsula. To date, this brings the large whale strandings for this region to almost three times the historical average.
The declaration of an unusual mortality event will allow NOAA and federal, state, and tribal partners to develop a response plan and conduct a rigorous scientific investigation into the cause of death for the stranded whales.
“NOAA Fisheries scientists and partners are very concerned about the large number of whales stranding in the western Gulf of Alaska in recent months,” said Dr. Teri Rowles, NOAA Fisheries’ marine mammal health and stranding response coordinator. “While we do not yet know the cause of these strandings, our investigations will give us important information on the health of whales and the ecosystems where they live. Members of the public can greatly assist the investigation by immediately reporting any sightings of dead whales or distressed live animals they discover.”
Predation, starvation, or disease could be behind the deaths, but researchers say there have been few signs of physical trauma to the whales. The more likely culprit is unusual water conditions.
Over the past two years, a large mass of warm water that climatologists have dubbed “the blob” has persisted in the north Pacific, and El Niño 2015 is pushing more warm water into the region.
The unusually warm and calm seas are believed to be behind a series of toxin-producing algae blooms – record-breaking in size and duration – stretching from southern California to the Aleutian Islands. Clams sampled near the town of Sand Point, Alaska were found to have toxin levels more than 80 times what the FDA says is safe for human consumption, said Bruce Wright, a scientist who studies toxic algal blooms for the Aleutian and Pribilof Islands Association. The levels were ten times anything Wright had previously recorded.
How do you explain a person seemingly legitimately trained in science drifting off and becoming more and more of a science denier?
In the case of Judith Curry I was unwilling to think of her as a full on science denier for a long time because her transition into denierhood seemed to be going very slowly, methodologically. It was almost like she was trying to drift over into denier land and maybe bring a few back with her. Like some people seem to do sometimes. But no, she just kept providing more and more evidence that she does not accept climate science’s concensus that global warming is real, caused by human greenhouse gas polution, involves actual warming of the Earth’s surface, and is important.
And lately she has added to this slippery sliding jello-like set of magic goal posts yet another denier meme. She is certain, after a convoluted review of “evidence” that one of the classic examples of deniers lying, deniers making stuff up to confuse and mislead policy makers, reporters, and the public, is real.
It is not real but she says it is real. If you were looking for a last straw required to place Judith Curry plainly and simply and undoubtedly in the category of Climate Science denier, this straw has fallen heavily on the camelid’s aching overburdened back. If you were looking for that one last fact that determines the balance of argument in favor (vs. against) Judith Curry being either nefarious (as all those who intentionally deny this important area of science must be) or just plain (and inexcusably) stupid (the only alternative explanation for pushing climate science denialism) than that fact has arrived.
What the heck am I talking about? This.
I’ve talked about it here. Go read that and the 100+ comments on it. In that post I contextualize and quote the following words from this source:
One e-mail Phil Jones of CRU sent to my coauthors and me in early 1999 has received more attention than any other. In it, Jones both made reference to “Mike’s Nature trick” and used the phrase “to hide the decline” in describing a figure … comparing different proxy temperature reconstructions. Here was the smoking gun, climate change deniers clamored. Climate scientists had finally been caught cooking the books: They were using “a trick to hide the decline in global temperatures,” a nefarious plot to hide the fact the globe was in fact cooling, not warming! …
The full quotation from Jones’s e-mail was …, “I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (i.e. from 1981 onwards) and from 1961 for Keith’s to hide the decline.” Only by omitting the twenty-three words in between “trick” and “hide the decline” were change deniers able to fabricate the claim of a supposed “trick to hide the decline.” No such phrase was used in the e-mail nor in any of the stolen e-mails for that matter. Indeed, “Mike’s Nature trick” and “hide the decline” had nothing to do with each other. In reality, neither “trick” nor “hide the decline” was referring to recent warming, but rather the far more mundane issue of how to compare proxy and instrumental temperature records. Jones was using the word trick [to refer to] to an entirely legitimate plotting device for comparing two datasets on a single graph…
The reconstruction by Briffa, (see K. R. Briffa, F. H. Schweingruber, P. D. Jones, T. J. Osborn, S. G. Shiyatov, and E. A. Vaganov, “Reduced Sensitivity of Recent Tree-Growth to Temperature at High Northern Latitudes,” Nature, 391 (1998): 678–682) in particular …
…was susceptible to the so-called divergence problem, a problem that primarily afflicts tree ring density data from higher latitudes. These data show an enigmatic decline in their response to warming temperatures after roughly 1960, … [Jones] was simply referring to something Briffa and coauthors had themselves cautioned in their original 1998 publication: that their tree ring density data should not be used to infer temperatures after 1960 because they were compromised by the divergence problem. Jones thus chose not to display the Briffa et al. series after 1960 in his plot, “hiding” data known to be faulty and misleading—again, entirely appropriate. … Individuals such as S. Fred Singer have … tried to tar my coauthors and me with “hide the decline” by conflating the divergence problem that plagued the Briffa et al. tree ring density reconstruction with entirely unrelated aspects of the hockey stick.
In hindsight, the way the Climategate emails was rolled out, after very careful scrutiny by the targeted bloggers, was handled pretty responsibly. Lets face it – “Mike’s Nature trick” to “hide the decline” means . . . “Mike’s Nature trick” to “hide the decline.”
That statement by Curry is demonstrably wrong. That is a fact borne of logical and scientific examination of the information, and information is not lacking. Curry is wrong.
Beyond that, I think, as implied above, she is either doing something here that is morally wrong (lying to slow down action on climate change) or stupid (she is not smart enough to understand what she is looking at). Here, I want to be clear. The argument that Curry is wrong is logical. Ends there. She’s wrong. The idea that she is either immoral or stupid is both my opinion and NOT an argument about her wrongness. I am not making an ad hominem argument. If you think that is an ad hominem argument then you don’t know what an ad hominum argument is (and isn’t).
And yes, I understand that this is a rather insulting thing to say, that one is either immoral or a dumbass. But it is my children’s future that is at risk here. Expect insults.
Cherry-pickin’ a bit of temperature data
And tryin’ to claim that climate change is in hiatus
It’s not, the trends are still going straight up
But they ain’t tryin’ to change their minds once they’re made up
In 1992 my mama’s thesis
Was about CO2 and Svante Arrhenius
So if you try to tell me that climate change isn’t serious
You’re dissin’ my mama, yup I’m kinda cliquish
Climate models employ piles of data and sophisticated computational techniques to predict what will happen in the future. Sometimes they predict what happened in the past as well. That is important to test the models (because we might know what happened in the past), or to fill in the blanks (we don’t always know exactly what happened in the past) or to understand complex climate systems better.
If you glance at the science denier rhetoric (mainly on blogs, you won’t find much in the peer reviewed literature because it isn’t good science) you’ll see repeated claims that climate models that try to predict global warming don’t match the actual observations of global warming. Most of the time, this claim is simply wrong. Perhaps an improper measurement of warming (like temperatures up higher in the atmosphere where we actually expect cooling rather than warming) is being used, which constitutes a lie. In other cases observed warming is within the model projections, but tracks off to one side (usually the low side) of the average expectation, but remains within the margin of error. This is either a misunderstanding of how the science works, or a willful misrepresentation. (Again, a lie.) But there are actually two legitimate areas where certain climate models seem to overstate observed warming. A recent post by John Abraham at the Guardian explores these areas.
First there is the question of where the warming is observed. We measure warming in several parts of the Earth’s surface. (See “What does “Global Warming” Mean?) One is surface temperatures at about head height, over land, via a gazillion weather stations many of which have been in operation since the 19th century. The other is at the surface of the sea, using a combination of older measurements taken from ships and more recent satellite observations. In addition, we have measurements of the deeper ocean itself, usually averaged out over some depth such as the top 700 meters, or the top 2,000 meters. This combines older and new ship our buoy measurements but tend to not go back in far in time as the land and sea surface measurements.
John Abraham has spent a lot of effort looking at ocean temperatures at depth. He and I recently published this item, and he’s done a lot of additional work on it. The total amount of heat added to the Earth’s surface from anthropogenic warming (caused mainly by greenhouse gasses such as carbon dioxide) is divided between the ocean and the surface, with the ocean taking up much of that heat. I liken the system to a dog with a wagging tail. The ocean is the dog, the surface temperatures, making up a small part of the overall system and being much more variable, is the tail.
We separated the world’s oceans into the Atlantic, Pacific, and Indian. All three of these oceans are warming with the Atlantic warming the most. We also calculated the ocean heating by using 40 state-of-the-art climate models. Over the period from 1970, the climate models have under-predicted the warming by 15%.
And here you can see a number of climate models superimposed over the observed heating in the top 700 meters of the ocean (the red line):
In a more recent post, Abraham asks the question, “ how have the models done at predicting the changes in air temperatures?”
As noted, global surface temperature is estimated in part from a bunch of thermometers around the globe, but these thermometers were not placed there for this purpose. They are weather stations set up to help track the weather, not to address questions of climate change. They are not evenly distributed, and there are huge gaps in the surface coverage, most notably in the Arctic and interior Africa, both regions where recent warming has probably been greater than elsewhere. In order for these temperature data to be used, they have to be carefully employed in a computational system that helps fill in the gaps. There are other complexities beyond our scope here. Suffice it to say that when a bunch of different groups of scientists (i.e., the British meteorology office, NASA, NOAA, the Japan Meteorological agency, and various university based groups) take on the task of estimating surface temperatures, they all do it a bit differently and thus turn up with slightly different curves.
This is true as well with sea surface temperatures. There is more than one way to measure sea surface temperature, or more exactly, to take existing data and turn it into a useful estimate of sea surface temperatures.
In addition, the data are cleaned up over time as mistakes are found, the basic computational approach used may be updated to make it more precise, and the overall approach to computation may be changed to make it more accurate.
Over time, two clear patterns have emerged. First, if you take all of the different measurements of surface temperature over time spanning from the 19th century to the present, lay them all out in front of you and step back about two meters and squint slightly, you can’t see the difference among them. They all look the same, they all tell the same story. They all have a handful of notable ups and downs along the generally upward march of surface temperatures with industrial pollution. You have to look at the graphs all on the same axes, together, to see the differences, and the differences are minor. This tells us that all the different approaches to processing a largely overlapping set of data end up with the same basic result. So many smart minds working with the best available science all produce the same result. How boring. But also, how reassuring that the science is being done right.
The second pattern emerges when we look at these graphs as they are produced over time. Various groups have said, “hey wait a minute, we’re missing this” or “we’re missing that” factor. Urban heat island effects may change the data! What about the Arctic! Interior Africa! Our satellites were recalibrated what does that do? Etc.
Over time, and honest, well informed, diligent effort by many groups to improve the measurement of the Earth’s surface temperature has resulted in a series of slightly different graphs, and in each and every case of which I’m aware, the resulting, more recent and better done graphs show more warming, and various periods of relative flatness have become steeper (going upwards).
So, what John Abraham has done is to take some of the more recently processed, better quality data and compared it to the usual models to see how well the models have done. They did well.
He based his discussion on a comparison of the most recent climate model simulations with actual global surface temperature measurements as numerically summarized by NASA’s Gavin Schmidt, shown here:
John has superimposed 2015 so far (the star).
This shows the most current computer model results and five current temperature data sets. The dark line is the average of the models, and the various colored lines are the temperature measurements.
The dashed line is slightly above the colored markers in recent years, but the results are quite close. Furthermore, this year’s temperature to date is running hotter than 2014. To date, 2015 is almost exactly at the predicted mean value from the models. Importantly, the measured temperatures are well within the spread of the model projections.
Too Hot
This is the year of the heatwave. We’ve had heat waves off and on for the last few years, but it seems that there are more now than ever before. While some have tried to argue that global warming can’t really cause warming (sometimes expressed as heat waves), it does.
Climate Scientist Stefan Rahmstorf has a blog post, in German, about a current heat wave in Europe. He notes (rough translation):
Europe is currently experiencing the second major heat wave this summer. On 5 July, according to the German Weather Service , a never before measured in Germany temperature reached 40.3 ° C in Kitzingen. But a month later, on August 7, this century record has been revised…One might speculate that a single heat wave could be simply due to chance. If you look at the temperature data, however, in their entirety it is immediately clear that extreme heat has become more common over several decades. (Apologies for errors in translation.)
And he shows this graph:
Percentage of global land area where the temperatures over a month were two or three standard deviations above the average from 1950 to 1980. Two standard deviations (orange) could be described as “very hot”, three standard deviations (dark red) as “extremely hot”. Source: Coumou and Robinson 2013
Egypt’s state news agency says 21 more people have died due to a scorching heat wave, raising this week’s death toll to more than 60.
The official MENA news agency said Wednesday that the latest deaths are from the previous day, mostly elderly people. It says 581 people are in hospital for heat exhaustion.
The Mideast has been hit by a heat wave since late July. Egyptian summers are usually hot, but temperatures this week soared to 46 degrees Celsius (114 degrees Fahrenheit) in the south.
At least 40 people had died on Sunday and Monday, including detainees and patients in a psychiatric hospital, according to officials. It wasn’t immediately clear whether Tuesday’s death toll includes a German national living in the southern city of Luxor who died from heatstroke.
Bill Maher and Penn State meteorology professor Michael Mann discuss the “settled science” of climate change and the lack of public engagement on the issue. Dr. Mann is the co-author of “Dire Predictions: Understanding Climate Change.”
There are two new scientific research papers looking at variation over the last century or so in global warming. One paper looks at the march of annual estimates of global surface temperature (air over the land plus sea surface, not ocean), and applies a well established statistical technique to ask the question: Was there a pause in global warming some time over the last couple of decades, as claimed by some?
The answer is, no, there wasn’t.
The paper is open access, is very clearly written so it speaks for itself, and is available here. One of the authors has a blog post here, in German.
The other paper looks at the so called global warming “pause” and interrogates the available data to see if the pause is supported. It concludes that it isn’t. The paper is written up in a blog post by one of the authors, here.
I’ll give you an overview of the findings below, but first, a word from the world of How Science Works.
It’s the variation, stupid
No, I’m not calling you stupid. Probably. I’m just paraphrasing Bill Clinton to underscore the importance of variation in science. The new paper examines variation in the global surface temperature record, so this is an opportunity to make this point.
Much of the time, science is about measuring, understanding, explaining, and predicting variation. This is a point non-scientists would do well to grasp. One of the reasons non-scientists, especially those engaged in policy making (from voter to member of Congress to regulatory agent to talking head) need to understand this better is because variation is one of the most useful tools in the denier tool kit. If your objective is to deny or obfuscate science, variation is there to help you.
Global warming, the increase in the Earth’s surface and ocean temperatures caused by the human caused increase in greenhouse gas, is a system with plenty of variation. The sources of variation are myriad, and the result is that the measurement of air temperature, sea surface temperature, and deeper ocean temperature appears as a set of squiggly lines.
In many systems, variation exists at more than one scale.
So, at the centennial scale, we see global surface temperatures not varying much century by century for a thousand years, then the 20th century average is higher than the previous centuries, and the 21st century average, estimated by 15% of the years of a century, is higher still. That is the effect of industrialization, where we shift from using energy from human and animal work, together with a bit of wind and water power, to using energy stored in carbon bonds in fossil fuels. This combined with population increase and increasing demands to support a consumer-driven comfort-based lifestyle have caused us to release fossil carbon into the atmosphere at an alarming rate.
At the decadal scale, we see a few recent decades that stick up above the others, and a few that are lower than others or at least don’t go up as much as others. Over the last 100 years, the decadal average temperatures have gone up on average, but with variation. The primary explanation for this variation is two fold. First, there is an increase in the absolute amount of greenhouse gas, and the rate at which we are adding greenhouse gasses to the atmosphere, so over time, greenhouse gasses have become the main determinant of temperature change (causing an increase). Earlier on, when greenhouse gas concentration was lower, other factors had a bigger impact. The second (and related) explanation is variation in aerosols, aka dust, in the atmosphere from various industrial processes, volcanoes, and such. Decadal or multidecadal variation over the last century has been mainly caused by aerosols, but with this effect diminishing in its importance as it gives way to the increasingly important role of greenhouse gas.
At a finer scale, of a year or a few years, we see variation caused mainly by the interaction of the surface (the air and the sea surface) and the upper ocean (this is sometimes examined for the top, say, 700 meters, other times, for the top 2000 meters, etc.) When we look at just ocean temperatures or just surface temperatures, we see a lot of squiggling up and down on an ever increasing upward trend. When we look at both together, we note that the squiggles cancel out to some extent. The ocean warmed considerably during recent years when the surface warmed more slowly. This is because heat is being exchanged back and forth between the surface and the deeper sea in a away that itself varies.
That is the simple version. In reality things are more complex. Even though ocean and surface temperatures vary from year to year, with the major variations caused by El Nino and La Nina events in the ENSO cycle, there are longer term variations in how this exchange of heat trends. This time scale is in the order of several decades going in one direction, several decades going in the other direction. (see this post) Then, this sort of variation may have much larger scales of change, at century or even millennial time scales, as ocean currents that facilitate this exchange, undergo major changes, which in turn alters the interaction of the surface and the sea. And, of course, both sea and ocean temperature can affect the major ocean currents, so there is a complex causal interaction going in both directions between those two sources of variation.
This is not a digression but it is annoying
Have you ever been annoyed by someone who makes a claim about the health benefits, or negative effects, of some kind of food or other ingestible substance? You know, one of those totally non-scientific “findings” from the usual internet sources. Here is a little trick you can do if you want to challenge such a claim.
In order to truly evaluate a health related claim, and have that evaluation be credible, you have to be able to do one of the following things, depending on the claim. Being able to do this is not enough to validate your expertise, but it is a starting point. It is a gate-keeper thought experiment. If you can’t do this, then you can’t really make the claim you are making with any credibility.
Name all the parts of a cell and what they do (for many health claims, especially those that have to do with diet, energy, metabolism, etc.)
Name all the different components of the immune system and explain how they work in detail (for many disease or illness related claims).
Describe, in detail, the digestive process, i.e., the process of food sitting on a plate being ingested and eventually being used by a human body, at the molecular level (for many claims about the beneficial or negative effects of certain foods, or the benefits of various dietary supplements).
You might be a climate scientist if …
All that stuff I said above about variation is the very simple version of what happens in the climate with respect to global surface temperature imbalance and global warming. If you read what I wrote and the whole time were thinking things like “yeah, but, he’s totally glossing this” or “no, it isn’t that simple, what really happens is…” then you might be a climate scientist.
If, on the other hand, this extensive tl;dr yammering on variation seemed senseless or a waste of time, or you didn’t find it interesting or don’t get the point, the you may not be prepared to evaluate claims like the one about the so-called “pause” or “hiatus” in global warming. More importantly, there is a good chance that a person making the claim that there has been such a pause is unprepared to do so, just as the person claiming that wearing a $50 fragment of a discarded circuit board around their neck will protect them from EMF can not really make that claim because they are a total dumb-ass when it comes to energy fields and cell biology.
Or, the person making the claim (most common in the area of global warming) is just trying to fool somebody. They are like the person who sells the fragment of the discarded circuit board.
Change Point
The first paper is “Change Points of Global Temperature” by Niamh Cahill, Stefan Rahmstorf and Andrew Parnell, published in IOP Science Environmental Research Letters.
A long series of data may demonstrate the outcome of a set of variables where all the variables act in similar ways over time, and any trend plus or minus variation will be clear. But if the variables change in their level of effect over time, it may be that parts of the long term data series need to be treated separately. This requirement has led to the development of a number of statistical techniques to break a series of data up into different segments, with each segment having a different statistical model applied to it.
The statistical approaches to this problem initially arose in an effort to better understand variation in the process of making key electronic components in the telecommunications industry. An early method was the “Control Chart” developed by Walter A. Shewhart at Bell Labs. The method allowed engineers to isolate moments in time when a source of variation contributing to mechanical failure changed, perhaps because some new factor came into play.
More recently, the statistical method of “Change Point Analysis” was developed to provide a better statistical framework for identifying and assessing the statistical significance of changes in sources of variation. The process involves determining whether or not a change in the sources of variation has occurred, and also, estimating if multiple change points have occurred. The process is pretty complicated, numerically, but is automated by a number of available statistical tools.
The new paper attempts to assess the reality of a “pause” or “hiatus” in global surface temperature increase using change point analysis. The change point analysis used four of the major commonly used data sets reflecting surface temperature changes. In each case, they found three change points to be sufficient to explain the medium to long term variation in the data. Most importantly, the most recent detectable change point was in the 1970s, after which there is no detectable change in the trend of increasing global temperature.
The results of the analysis are summarized in this graphic:
Figure 1. Overlaid on the raw data are the mean curves predicted by the three CP model. The grey time intervals display the total range of the 95% confidence limits for each CP. The average rates of rise per decade for the three latter periods are 0.13 ± 0.04 °C, ?0.03 ± 0.04 °C and 0.17 ± 0.03 °C for HadCRUT, 0.14 ± 0.03 °C, ?0.01 ± 0.04 °C and 0.15 ± 0.02 °C for NOAA, 0.15 ± 0.05 °C, ?0.03 ± 0.04 °C and 0.18 ± 0.03 °C for Cowtan and Way and 0.14 ± 0.04 °C, ?0.01 ± 0.04 °C and 0.16 ± 0.02 °C for GISTEMP.
Those who claim that there was a pause in global warming point to certain dates as the origin of that pause. The authors tested that idea by forcing the change point analysis to assume that this was correct. The alleged starting points for a global warming hiatus failed the statistical test. They are not real. The authors determined that the change point analysis “…provides strong evidence that there has been no detectable trend change in any of the global temperature records either in 1998 or 2001, or indeed any time since 1980. Note that performing the CP analysis on the global temperature records excluding the 2013 and 2014 observations does not alter this conclusion.”
In addition, even though the alleged starting points for a global warming hiatus were found to be bogus, they were found to be more bogus in one of the four data sets, that developed by Cowtan and Way, which in turn is generally thought to be the data set that eliminates most of the biases and other problems found in this sort of information. In other words, using the best representation available of global surface temperature increase, the so called hiatus is not only statistically insignificant, it is even less significant!
But that wasn’t enough. The authors took it even a step further.
Finally to conclusively answer the question of whether there has been a ‘pause’ or ‘hiatus’ we need to ask: If there really was zero-trend since 1998, would the short length of the series since this time be sufficient to detect a CP? To answer this, we took the GISTEMP global record and assumed a hypothetical climate in which temperatures have zero trend since 1998. The estimated trend line value for 1998 is 0.43 °C (obtained by running the CP analysis on the original data up to and including 1998). Using this, we simulated 100 de-trended realizations for the period 1998–2014 that were centered around 0.43 °C. We augmented the GISTEMP data with each hypothetical climate realization and ran the four CP model on the augmented data sets. This allowed us to observe how often a fourth CP could be detected if the underlying trend for this period was in fact zero. Results showed that 92% of the time the four CP model converged to indicate CPs in approximately 1912, 1940, 1970 and a fourth CP after 1998. Thus, we can be confident that if a significant ‘pause’ or ‘hiatus’ in global temperature did exist, our models would have picked up the trend change with a high probability of 0.92.
Climate change deniers are always trying to make the graphs go down. The graphs do not cooperate.One is forced, sadly, to think about what deniers might say about any new climate change study. In this case, I think I know what they might say. Look again at the graph shown above. We see two periods when temperatures seem to be going down, and two periods when temperatures seem to be going up. So, half the time, they are going down and half the time they are going up, right? So, what happens if, as suggested by some climate deniers, we are due for a downward trend? Maybe there will be enough multi-decadal downward trends over the next century or so to significantly attenuate the overall trend. Hey, we might even see cooling. Right?
Well, no. For one thing, as mentioned above, the overall pattern has been an increase in the importance of greenhouse gasses as the variable controlling surface temperatures. Whatever factors caused the flattish or downward trends many decades ago may still be in place but are relatively less important from now on, even if we quickly curtail CO2 output. Also, one of those factors, aerosols, is reduced permanently (we hope). Industrial pollution, in the past, caused a lot of aerosols to be released into the atmosphere. This has been reduced by changing how we burn things, so that source attenuation of surface temperatures is reduced. Also, as noted above, there are multi-decadal changes in the relationship between the surface (air and sea surface) and the ocean, and at least one major study suggests that over coming decades this will shift into a new phase with more surface heating.
I asked author Stefan Rahmstorf to comment on the possibility of a future “hiatus.” He told me that one is possible, but “I don’t expect that a grand solar minimum alone could do it (see Feulner and Rahmstorf ERL 2010). Maybe an exceptionally large volcanic eruption could do it but it would have to be far bigger than Pinatubo, which did not cause one.” He also notes that some IPCC climate models have suggested a future slowdown, and the possibility of cooling in not non-zero. The key point, he notes, is “it just has not happened thus far, as the data analysis shows.”
Author Andrew Parnell noted, “I think anybody who claims that these current data demonstrate a hiatus is mistaken.”
Think there is a global warming hiatus? Slow down a second…
The second paper is “Lack of evidence for a slowdown in global temperature” by Grant Foster and John Abraham. Foster and Abraham start out by noting that there is a widely held belief, even among the climate science community, “…that the warming rate of global surface temperature has
exhibited a slowdown over the last decade to decade and a half.” They examine this idea “…and find no evidence to support claims of a slowdown in the trend.”
The authors note that most of the discussion of global warming involves reference to “ the relatively small thermal reservoir of the lower atmosphere” (what I refer to above as the “surface”), but since this is only a small part of the planets heat storage, this can be misleading. When the ocean is taken into account, we see no slowdown in warming. The paper by Foster and Abraham refers to the above discussed paper on change point analysis, so I’ll skip that part. The remaining thrust of the paper is to apply some basic statistical tests to the temperature curves to see if there is a statistically valid slowdown.
They derived residuals, using the GISS data set, for the last several decades, indidating the divergence of each year from an expected value given an upward trend. This looks like this:
They then took sets of adjoining residuals, and tested the hypothesis “This set of numbers is different from the other numbers.” If there was a statistically significant decrease, or increase, in temperature change for several years it would show up in this analysis. The statistical test of this hypothesis failed. As beautiful as a pause in global warming may seem, the idea has been killed by the ugly fact of ever increasing temperatures. To coin a phrase.
Then…
As a last attempt to find evidence of a trend in the residuals, we allowed for models in which not only the slope (the warming rate) changes, but the actual value itself. These are discontinuous trends, which really do not make sense physically … but because our goal is to investigate as many possible changes as is practical, we applied these models too. This is yet another version of change-point analysis, in which we test all practical values of the time at which the slope and value of the time series change. Hence it too must be adjusted for multiple trials.
Again, no statistical significance. If you look at the global temperature curve, and see a pause, what you are really seeing is noise.
Foster and Abraham conclude:
Our results show that the widespread acceptance of the idea of a recent slowdown in the increase of global average surface temperature is not supported by analytical evidence. We suggest two possible contributors to this. First, the natural curiosity of honest scientists strongly motivates them to investigate issues which appear to be meaningful even before such evidence arrives (which is a very good thing). Second, those who deny that manmade global warming is a danger have actively engaged in a public campaign to proclaim not just a slowdown in surface temperature increase, but a complete halt to global warming. Their efforts have been pervasive, so that in spite of lack of evidence to back up such claims, they have effectively sown the seeds of doubt in the public, the community of journalists, and even elected officials.
Ultimately sea levels will rise several feet, given the present levels of CO2 in the atmosphere. We already knew this by examining paleo data, and finding periods in the past with similar surface temperatures and/or similar atmospheric CO2 levels as today.
I put a graphic from a paper by Gavin Foster and Eelco Rohling at the top of the post. It does a good job of summarizing the paleo data.
If we keep pumping CO2 into the atmosphere at current, or even somewhat reduced, levels for a few more decades, the ultimate increase in sea levels will be significant. Find the 400–500 ppm CO2 range on the map and notice that the average sea level rise in times past, indicated by the horizontal orange-reddish line, is 14 meters.
Let me rephrase that to make it clear. We have already caused something like 14 meters of sea level rise. Like the horrifically sad words uttered by a movie or TV character who has received a fatal wound and turns to the killer, uttering “You’ve killed me” (then they die), we’ve done this. It is just going to take some time to play out. But it will play out.
A conservative estimate is that likely sea levels will rise 8 meters or more, quite possibly considerably more. But generally, people who talk about sea level tend to suggest that this will take centuries. Part of the reason for that is that it takes a long(ish) time for the added CO2 to heat up the surface, then it takes a while for that heat to melt the ice sheets. However, there is no firm reason to put a time frame on this melting.
A new paper that is making a great deal of news, and that is still in peer review, suggests that the time frame may be shorter than man have suggested. We may see several meters of sea level rise during the lifetime of most people living today.
What is not known
We don’t really how long this will take. Looking at the paleo record, we are lucky to get two data points showing different ancient sea levels that are less than a thousand years apart. There are a few moments during the end of the last glaciation where we have data points several centuries apart during which sea levels went up several meters. We don’t have a good estimate for the maximum rate at which polar ice caps and other ice can melt.
The current situation is, notably, very different from those periods of rapid sea level rise. The amount of CO2 in the atmosphere is approximately double the Pleistocene average, and the rate at which CO2 levels and temperatures have gone up has not been seen in tens of millions of years. Whatever rate of sea level rise over the last several tens of thousands of years must be regarded as a minimum, perhaps a very low minimum.
What is new
The new paper argues for more sea level rise, ultimately, than many others have suggested, but it is still within the range of what we had already guessed from the paleo record. Most current research on the rate of glacial melting show relatively slow levels compared to what the new paper suggests. In particular, the new paper suggests that this is wrong, and that we may see three meters of sea level rise over the next fifty years.
The paper is very complex and covers a lot of ground that I will not attempt to address here. The tl;dr is that the researchers model the current melting of ice, and finds that the rate is accelerating over time. This means that current rates are a gross underestimate of the rate of sea level rise.
Here are twointerviews with Michael Mann on the new work.
Mann talks about some of the effects of sea level rise, including global effects. We are already seeing food prices being affected now and then by climate catastrophes. Consider the fact that much of the rice grown in southeast Asia is grown on land that will be inundated by this sea level rise. This applies to the US as well. This combined with increased drought in places that are not flooding, and social unrest such as occurred in Syria when crops fail – causing further agriculture in those areas to simply stop happening – will cause a major food crisis in the near future. Our children and grandchildren will be hungry, at war, living in a post-civilization world. That is the world those who deny climate science and stand in the way of taking action are causing.
Here is the abstract of the paper:
There is evidence of ice melt, sea level rise to +5–9 meters, and extreme storms in the prior interglacial period that was less than 1°C warmer than today. Human-made climate forcing is stronger and more rapid than paleo forcings, but much can be learned by combining insights from paleoclimate, climate modeling, and on-going observations. We argue that ice sheets in contact with the ocean are vulnerable to non-linear disintegration in response to ocean warming, and we posit that ice sheet mass loss can be approximated by a doubling time up to sea level rise of at least several meters. Doubling times of 10, 20 or 40 years yield sea level rise of several meters in 50, 100 or 200 years. Paleoclimate data reveal that subsurface ocean warming causes ice shelf melt and ice sheet discharge. Our climate model exposes amplifying feedbacks in the Southern Ocean that slow Antarctic bottom water formation and increase ocean temperature near ice shelf grounding lines, while cooling the surface ocean and increasing sea ice cover and water column stability. Ocean surface cooling, in the North Atlantic as well as the Southern Ocean, increases tropospheric horizontal temperature gradients, eddy kinetic energy and baroclinicity, which drive more powerful storms. We focus attention on the Southern Ocean’s role in affecting atmospheric CO2 amount, which in turn is a tight control knob on global climate. The millennial (500–2000 year) time scale of deep ocean ventilation affects the time scale for natural CO2 change, thus the time scale for paleo global climate, ice sheet and sea level changes. This millennial carbon cycle time scale should not be misinterpreted as the ice sheet time scale for response to a rapid human-made climate forcing. Recent ice sheet melt rates have a doubling time near the lower end of the 10–40 year range. We conclude that 2°C global warming above the preindustrial level, which would spur more ice shelf melt, is highly dangerous. Earth’s energy imbalance, which must be eliminated to stabilize climate, provides a crucial metric.
Every month NASA GISS comes out with the new data for the prior month’s global surface temperature, and I generally grab that data set and make a graph or two. In a way this is a futile effort because the actual global surface temperature month by month is not as important as the long term trend. But at the same time it is a worthy exercise because it is news, and especially lately, we seem to be breaking records of one kind or another every month.
This month I was out of town and actually traveling sans computer, when the NASA GISS data became available. So, for me to produce the graphs and report the news at this point is not that interesting. But, I do want to keep you updated.
June was, it turns out, a warm month. But also, there were corrections to the original data set this month that may cause some confusion. There are often, nearly monthly, but generally tiny corrections in the data, but this month the corrections were more extensive and involved changes in the way the monthly temperature anomalies are calculated.
June 2015 turns out to be the hottest June on record, at a whopping 0.80 degrees C above the 1951-1980 baseline used by NASA. That baseline is, of course, already well above the pre-industrial baseline. We are clearly above 1 full degree C above that.
The highest anomaly this year is now March at 0.90°C, which makes it the third hottest March after March 2010, at 0.92°C and March 2002 at 0.91°C.
2015 is still hottest on record so far. With the adoption of ERSST v4, some of the temperatures are higher. So are those of some other years, particularly in 2010, temperatures have been upped quite a bit. But all have changed.
April and May are still relatively cool, unlike in some other data sets. By cool I don’t mean cold. May was 0.76C above the 1951-1980 mean. It’s just that most people thought it would be among the hottest of Mays, particularly since ERSSTv4 was very high in May this year.
The lowest anomaly was in April this year, at 0.74°C above the 1951-1980 mean.
The progressive year to date average up to and including June is 0.82°C above the 1951-1980 mean. In June 2010 it was 0.78°C above. (In June 2014, the hottest full year to date, it was 0.72°C above.)
Sou also has an update of her famous month to date chart, here. Go have a look.
The main change in the NASA GISS data is the use of ERSST v4 data for sea surface temperature. This changes all the NASA GISS data and requires that we throw out all our old graphs and make new ones. I’ll do that eventually. NOAA has also made this change.
One of the most important features of the new, and improved, data is that the so called “pause” in global warming looks a lot less like a pause than it did before, and it didn’t look much like a pause anyway. This of course has got the denialosphere all in a tizzy. And about that, we should really care not one bit. So that’s all I’ll say about it.
John Abraham, who has been making highly accurate predictions among his friends of what each month’s NASA GISS data will look like (I occasionally help him with this) has some bad news about the ocean:
As I have said many times on this blog, if you want to know how much “global warming” is happening, you really have to be able to measure “ocean warming”. That is because more than 90% of the excess energy coming to the Earth from greenhouse gases goes into the ocean waters. My colleagues and I have a new publication, which better characterizes this heating and also compares climate model predictions with actual measurements. It turns out models have under-predicted ocean warming over the past few decades. …
We separated the world’s oceans into the Atlantic, Pacific, and Indian. All three of these oceans are warming with the Atlantic warming the most. We also calculated the ocean heating by using 40 state-of-the-art climate models. Over the period from 1970, the climate models have under-predicted the warming by 15%.
I’ve put the graphic from that study above, and it has this caption:
(a) Upper (0–700 m) OHC, calculated using 40 CMIP5 models (gray lines; black line is the ensemble mean). The CMIP5 results are compared with the observation-based estimate using the strategies presented in this study (red line) and NODC mapping (dashed blue line). Two major volcanic eruptions are marked by the black arrows. (b) Annual global-averaged upper ocean warming rates from the CMIP5 model results (gray lines; red line is the ensemble mean) and from observations (blue line), computed from the first differences of OHC at 700 m (units: °C yr?1). Source: Institute of Atmospheric Physics.
Focusing on Earth, but also a few tidbits on wind, fire, and ice, some current news and observations about global warming.
Earth
As humans release greenhouse gas pollutants (mainly CO2) into the atmosphere, the surface of the Earth, and the top 2000 meters of the ocean, heat up. But some of the CO2 is absorbed into plant tissues and soil, as well as in the ocean or other standing water. Historically, about 30% of the extra CO2 is absorbed into the ocean, and another 30% converted into (mainly) plant tissue. We hope that enough CO2 is absorbed that the effects of greenhouse gas pollution is attenuated, at least a little. Unfortunately, there are two things that can go wrong. First, these “Carbon sinks” — places where the CO2 is either stored or converted into Carbon-based tissue, could stop working. Second, some of these Carbon sinks could reverse course and start releasing, rather than absorbing, Carbon.
The CO2 released in the atmosphere during any given time period starts a process of warming that takes years to finish. We know how much CO2 we have added to the atmosphere (we went from the mid 200’s ppm, parts per million, before this all started to 400ppm). We know how much we are currently releasing and we can estimate how much we will be releasing in coming years. Putting this all together with some very fancy physics and math, we can estimate the amount of surface warming over coming years. This calculation includes the Carbon sinks. If the Carbon sinks stop sinking Carbon, or worse, start releasing previously trapped Carbon, then future warming (next year, next decade, over the next century) will be greater than previously expected.
And there is now evidence that this is happening.
Andy Skuce has written up two pieces, here and here, that explain this. It is also written up here, and the original research is here.
This research suggests that some natural Carbon sinks are slowing down in the amount of Carbon they take in, or perhaps switching to releasing Carbon.
The problem is actually very simple to understand. In order for CO2 to be converted to O2 (free oxygen) and some combination of C and other elements (to make plant tissue), the other elements have to be available in sufficient quantity. For many terrestrial ecosystems, CO2 was a limiting factor (keeping water and sunlight out of the picture or constant). So, adding CO2 means more plant growth. But at some point, the other elements that are required to make plant tissue, such as Nitrogen and Phosphorous (otherwise known as fertilizer) are insufficient in abundance to allow plants to use that CO2. This would reduce or flatten out the amount of extra CO2 that can be trapped in solid form. At this point, the terrestrial biomass starts to release, rather than absorb, CO2.
Why would the terrestrial Carbon sink not simply stop absorbing Carbon, and start to release it? Well, because I as fibbing a little when I said this is simple. The more realistic version of the system has Carbon going in and out of the different parts of the system (atmosphere, ocean water, plant tissue, etc.). With warming temperatures, we expect the release of Carbon from terrestrial systems to increase in rate. So, before nutrient limitation is released, there is Carbon going in and Carbon going out, but on average, mostly going in. With Nutrient limitation on the system, when there isn’t enough Nitrogen or Phosphorus to match up with the CO2, the release continues while the absorption stops. But because of warming, the release not only continues, but increases. So, in coming decades, the net effect is that parts of the terrestrial ecosystem contributes to atmospheric CO2.
At present, climate scientists (mainly in the context of the IPCC) have estimates of future warming that involve estimates of how much CO2 we add to the atmosphere. All the known factors have been taken into account, including the Carbon cycle (which includes Carbon moving between the atmosphere, the ocean, and the plant and soil system at the surface. This research indicates that the numbers have to be changed to account for nutrient saturation.
This graph shows how it works. The black line is the increase in plant growth as originally modeled under a “high-emissions” scenario. This shows a 63% increase in plant growth by the end of the century owing to CO2 fertilization. The red line indicates the amount of extra plant growth that would actually happen due to limitations of Nitrogen. The blue lie indicates the amount of plant growth due to the limitation of Phosphorus. These are 29% and 20%, respectively.
If we include the increase in release of Carbon due to warming conditions (basically, more and faster rotting of dead plant tissue), the existing models produce the black line in the graph below. There is still an increase in plant growth, and the plant-based Carbon sink is still working. If limitations on nitrogen and phosphorus are considered, we get the red and blue lines.
This amounts, approximately, to adding about 14 years of human greenhouse gas pollution (at the current rate) to the time period under consideration (from now to 2100).
So that’s the news when it comes to climate change and the Earth. But what about the wind?
Wind
No new research here, just an observation. Where does wind really matter? Where do you really feel the wind? Wind is the expression of the large scale climate system (modified by local conditions) which is in turn the result of the spinning of the Earth and the heating of the planet unevenly by the sun, like it does. A valid rule of thumb is more heat, more wind, but that is a gross oversimplification. At a more complex level, more heat equals more wind doing different things in different places than usual, and also more water vapor in the air, and all this has to do with those times and places where we really feel the wind the most: Storms.
Tenney Naumer (of Climate Change: The Next Generation fame) came across an amazing graphic of the Earth, looking mainly at the Pacific, showing some wind.
The graphic is from here, and I added the “Storm World” just for fun. Except it isn’t really fun. The date of this graphic is, I think, July 5th or 6th.
Your homework assignment is to identify the named tropical storms shown in the graphic.
Fire
A few years ago there were some big fires. Australia burned, there were fires in California, Texas, Arizona, various parts of Canada, etc. Climate change and fire experts noted that there is an increase in fires because of global warming, but others argued that there was no significant increase, and we had had periods of abundant fires in the past. In truth, there was evidence of an increase, though maybe not very convincing to some. Also, past inclement conditions are a thing … recent global warming did not invent bad weather or extensive wildfires. But some of those past periods, like the 1930s in the US, are not evidence against current climate change, but rather, evidence of what to expect with climate change. Those periods are only barely as severe as the present state, are usually regional and not global, happened after greenhouse gas pollution was very much a thing and between periods of suppression of warming by aerosols (from volcanoes or industrial pollution). So they matter, but not because they disprove climate change (they don’t) but rather because these past events are windows into the future. But I digress.
The point is, a few years ago, those who are rightfully alarmed about climate change were pointing out the problem of increased wild fires referring mainly to research indicating a dramatic increase in wildfire potential, along with some evidence of actual increased wildfires. And others argued that until there were a lot more flames, there was not a problem.
Well, now we have the flames.
Yesterday (anecdote warning, this is not data) I went outside to check the mail and was assailed by a bank of smoke moving through my neighborhood. It smelled really bad. Assuming there was a house on fire, I dashed back into the house to grab my cell phone, in case I had to dial 911. Returning outside, I walked around and did not see anything obvious burning, but the smoke was coming in from the north. That ruled out a burning oil tank train (the tracks are from the south) and the local munitions dump on fire (that is to the west). But I still couldn’t see where the smoke was coming from. So, I hopped in the car and drove north a couple of blocks, and by the time I got to the nearby Interstate, it became clear that the smoke was simply everywhere, pretty uniformly.
I then guessed at the cause, and returned to my computer where I checked the Wundermap and some other sources. Yup: it was Canada and Alaska, thousands of miles away, pretty much on fire. Here are two graphics to illustrate this.
Glacial ice is melting, and it is melting faster every year. Earlier in the year we learned that Alaska (on fire, see above) has been losing mountain glacier and ice sheet water at an alarming rate. Now, we are seeing an amazing spike in melting on the surface of Greenland. From here:
The graph is of ice melt extent so far this year. The blue dotted line is the average over recent decades as in dicated. The grey area is 2 standard deviations around that average. The vast majority of observations (nearly 100%) would be in that grey area. The red line is this year. This is what you call unprecedented melting.
Why is this melting happening? Because Greenland is unusually warm, but as expected under global warming. Some of this melted ice will refreeze in the winter. Much of it, however, is going into the sea.
Humans have been releasing greenhouse gas pollution into the atmosphere for a long time now, and this has heated up the surface of the planet. This, in turn, has caused a number of alarming changes in weather. Several current weather events exemplify the effects of climate change.
Record High Temperatures Being Shattered
South Asia recently experienced a number of killer heatwaves, and that is still going on in the region. More recently, we’ve seen long standing record highs being broken in the American West. The Capital Climate group recently tweeted this list of records:
Hot Whopper puts this in some context and adds some other sources, here.
The extreme heat has even surged north into Canada. Cranbrook, in far southeast British Columbia at an elevation of about 3,000 feet, set a new all-time record high of 98 degrees (36.8 degrees Celsius) Sunday, according to The Weather Network.
Even Revelstoke, British Columbia – 130 miles north of the U.S. border, about 1,500 feet above sea level and better known for skiing – reached an amazing 103 degrees (39.5 degrees Celsius) Sunday.
As temperatures reached 36.7 °C at Heathrow, commuters were facing difficult journeys on the London Underground. One platform at Kings Cross underground station recorded 33 °C however the temperature on tubes is believed to be even hotter.
Charlotte Dalen, originally from Norway but now living in London, said: “It was pretty warm and very smelly. People were waving pamphlets to keep cool but it didn’t look like it was helping.”
The map at the top of the post of current heat anomaly estimates across the globe is from Climate Reanalyser.
An Unprecedented Tropical Cyclone
Raquel is a Pacific Tropical Cyclone (hurricane) which is the earliest to form in the region (The “Queensland Zone” as tracked by the Australian meteorologists) in recorded history. From the Bulletin:
TROPICAL Cyclone Raquel has formed in the south-west Pacific near the Solomon Islands, triggering the earliest cyclone warning on record issued for the Queensland zone.
“Certainly it’s a unique scenario,” Jess Carey, a spokesman from the bureau’s Queensland office, said. “Since we’ve been tracking cyclones with satellite-based technology, we haven’t seen one in July.”
The storm became a category 1 cyclone early on Wednesday morning and had a central pressure of 999 hPa about 410 km north of the Solomon Islands’ capital of Honiara as of just before 5am, AEST, the Bureau of Meteorology said. It is forecast to strengthen to a category 2 system on Thursday.
“The cyclone is moving southwest at about 16 km per hour and should gradually intensify over the next 24 hours as it approaches the Solomon Islands,” the bureau said in a statement. “The system will remain very far offshore and does not pose a threat to the Queensland coast.”
The official cyclone season runs from November 1-April 30. Any cyclone after May or before October is considered unusual.
Wildfires Gone Wild
Over the last several days and continuing, there have been extensive and unprecedented fires in the west as well. Drought in California has increased fire danger, and now things are starting to burn. This year the fires started earlier, with one of the largest fires having burned during a normally low-fire month, February. Also, fires are burning where they are normally rare. According to Will Greenberg at the Washington Post..
Cal Fire has already responded to 1,000 more incidents this year than they see on average annually. The agency reached that same landmark last year as well — but in September.
By the end of June, officials had fought nearly 3,200 fires.
In total, Cal Fire and the U.S. Forest Service have responded to fires stretching over 65,755 acres so far this year.
And this is just the beginning for California’s 2015 wildfire season.
Meanwhile, in Washington, where it has been dry and hot, hundreds have been forced to flee from some amazing wildfires. From the Guardian:
The wildfires hit parts of central and eastern Washington state over the weekend as the state is struggling with a severe drought. Mountain snowpack is at extremely low levels, and about one-fifth of the state’s rivers and streams are at record low levels.
Eastern Washington has been experiencing temperatures into the 100s, and last week Washington governor Jay Inslee issued an emergency proclamation that allows state resources to quickly be brought in to respond to wildfires.
The number of Alaska’s active wildfires is literally off the charts, according to a map recently released by the state’s Division of Forestry.
Over 700 fires have burned so far this summer, the most in the state’s history, and that number is only expected to get bigger as the state is experiencing higher temperatures, lower humidity and more lightning storms than usual, said Kale Casey, a public information officer for the Alaska Interagency Coordination Center, which serves as a focal point for state agencies involved in wildland fire management and suppression.
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