The report affirms that climate is changing and that this change is primarily caused by human activities, mostly the release of fossil carbon into the atmosphere by burning fuels. The report notes an increase in weather extremes and that these extremes are being recognized by the relevant climate science as linked to these human-induced changes.
Details about the committee, the report, and the process, are as follows:
A 60-person Federal Advisory Committee (The “National Climate Assessment and Development Advisory Committee” or NCADAC) has overseen the development of this draft climate report.
The NCADAC, whose members are available here (and in the report), was established under the Department of Commerce in December 2010 and is supported through the National Oceanic and Atmospheric Administration (NOAA). It is a federal advisory committee established as per the Federal Advisory Committee Act of 1972. The Committee serves to oversee the activities of the National Climate Assessment. Its members are diverse in background, expertise, geography and sector of employment. A formal record of the committee can be found at the NOAA NCADAC website.
The NCADAC has engaged more than 240 authors in the creation of the report. The authors are acknowledged at the beginning of the chapters they co-authored.
Following extensive review by the National Academies of Sciences and by the public, this report will be revised by the NCADAC and, after additional review, will then be submitted to the Federal Government for consideration in the Third National Climate Assessment (NCA) Report. For more information on the NCA process and background, previous assessments and other NCA information, please explore the NCA web-pages. The NCA is being conducted under the auspices of the Global Change Research Act of 1990 and is being organized and administered by the Global Change Research Program.
To simply access and read the draft report, please download the chapters below. However, if you would like to submit comments on the report as part of the public process, you will need to enter the “review and comment system” and register with your name and e-mail address and agree to the terms. All comments must be submitted through the review and comment system.
The UK Met Office, a climate agency, released some information about the immediate future, based on modeling. Briefly, it notes that natural cooling effect may temporarily ameliorate the increase in temperatures caused by global warming in some locals; it does not say that global warming is attenuated in any way whatsoever. It is more of a long term weather forecast than a climate change prediction.
The climate science denialist community, a community run by willfully wrong miscreants and with a following of mostly ignorant sycophants, and which only likes modeling when it seems to show what the denialists want it to show, made much inappropriate hay of thisleading to BBC Today to produce this headline:
“Met Office Does Not Believe that Global Warming Will Be As Severe As Previously Predicted”
When asked, the Met Office says they’d prefer the following headline to reflect what they were saying:
“Latest forecast for the next five years show that the earth will continue to be at record high levels, and there is a fair chance that new records will be made during that period.”
Here is the BBC fixing their mess-up:
Sad to see Today digging in rather than getting on board with a vigorous effort at making it right.
Looking just at the contiguous 48 states of the US, NOAA has determined that 2012 was the warmest year on record. It was also ranked second in “extreme” weather events including fires, major storms, and drought. Tornado activity was less than average.
The report came out yesterday and states:
In 2012, the contiguous United States (CONUS) average annual temperature of 55.3°F was 3.3°F above the 20th century average, and was the warmest year in the 1895-2012 period of record for the nation. The 2012 annual temperature was 1.0°F warmer than the previous record warm year of 1998. Since 1895, the CONUS has observed a long-term temperature increase of about 0.13°F per decade. Precipitation averaged across the CONUS in 2012 was 26.57 inches, which is 2.57 inches below the 20th century average. Precipitation totals in 2012 ranked as the 15th driest year on record. Over the 118-year period of record, precipitation across the CONUS has increased at a rate of about 0.16 inch per decade.
On a statewide and seasonal level, 2012 was a year of both temperature and precipitation extremes for the United States. Each state in the CONUS had annual temperatures which were above average. Nineteen states, stretching from Utah to Massachusetts, had annual temperatures which were record warm. An additional 26 states had one of their 10 warmest years. Only Georgia (11th warmest year), Oregon (12th warmest), and Washington (30th warmest) had annual temperatures that were not among the ten warmest in their respective period of records. A list of the annual temperatures for each of the lower-48 states is available here. Numerous cities and towns were also record warm during 2012 and a select list of those locations is available here. Each state in the CONUS, except Washington, had at least one location experience its warmest year on record. One notable warmest year record occurred in Central Park, in New York City, which has a period of record dating back 136 years.
Here’s a scary graphic:
Figure 2. Temperatures for the contiguous U.S. in 2012, compared to the previous record warmest and coldest years in U.S. history. The annual U.S. average temperature was 3.3°F above the 20th century average, and was an astonishing 1.0°F above the previous record, set in 1998. It is extremely rare for an area the size of the U.S. to break an annual average temperature record by such a large margin. Image credit: NOAA/NCDC, caption from Jeff Masters.
You can see the entire report here, and a summary here. A report on Fox News coverage of the report is here. Jeff Masters as Wunderblog discusses it here.
First, a word about the Australian Bureau of Meteorology’s position on climate change, heat, and fires. It has been suggested (by a commenter here) that the BoM is claiming that the current heat wave is not related to climate change, but rather, a matter of natural variability and a late arriving monsoon. But that is not true. The BoM has a different take on the current situation. From Ben Cubby, an Australian journalist:
The heatwave that has scorched the nation since Christmas is a taste of things to come, with this week’s records set to tumble again and again in the coming years, climate scientists said.
The hottest average maximum temperature ever recorded across Australia – 40.33 degrees, set on Monday – may only stand for 24 hours and be eclipsed when all of Tuesday’s readings come in. Previously, that record had stood since December 21, 1972.
‘‘The current heatwave – in terms of its duration, its intensity and its extent – is now unprecedented in our records,’’ the Bureau of Meteorology’s manager of climate monitoring and prediction, David Jones, said.
‘‘Clearly, the climate system is responding to the background warming trend. Everything that happens in the climate system now is taking place on a planet which is a degree hotter than it used to be.’’
Jones goes on to say that record-breaking temperatures will become more common in years to come, owing to global warming, though of course there will still be ups and downs because natural variation will be riding on top of a warming temperature baseline. He also notes that the changes in weather and effects on agriculture, water availability and general human health are playing out pretty much as predicted by scientists in numerous studies over the last several years. The article by Cubby also goes on to say that 2013 may end up being the hottest year on record.
It is interesting to note that Australian meteorologists have been forced to add a new color to their weather maps in order to depict the extremely warm temperatures. (The image at the top of this post uses the new color, or as they say in Australia, “colour.”
The high temperature averaged over Australia was 105°F (40.3°C), eclipsing the previous record of 104°F (40.2°C) set on 21 December 1972. Never before in 103 years of record keeping has a heat wave this intense, wide-spread, and long-lasting affected Australia. The nation’s average high temperature exceeded 102°F (39°C) for five consecutive days January 2 – 6, 2013–the first time that has happened since record keeping began in 1910.
Naturally, as with anything that happens in Australia or America, the heat wave is causing an international incident. Get Energy Smart Now notes:
Some might say that those ‘Down Under’ have a competitive streak with Americans — great allies but truly ecstatic when an Aussie beats an American at the Olympics. At times, however, competition can go too far. And, such is the case with the #BigAussieHeat. After the United States set massive numbers of high temperature records in 2012 … it seems that Australia is on the path to top America’s nightmarish heat wave conditions with environmental conditions.
Next thing you know the’ll be trying for the America’s Cup again!
And now, from this report, a video on Bush Fires in Tasmania:
And, rescuing a Koala:
Anthropogenic global warming: It’s real, and it is impacting us now.
Thanks to Stephan Lewandowsky, who has been providing me with very useful information about the situation down under, where he and his family are sweltering.
Australia is experiencing a heat spell. The Climate Information Services of the Australian Bureau of Meteorology has issued a special statement (I’ll provide some details below). This is not unexpected, since over the last few years global warming due to the human release of large amounts of fossil Carbon into the atmosphere has been heating everything up. In fact, a paper that came out mid (southern) winter 2008 predicted that by the end of the century, extreme high temperatures in Australia would reach 50 degrees or more. I’ll provide some data for that too. But first, since most of the readers of this blog live in the US I’ll provide a table showing the relationship between degrees F an degrees C.
C
F
20
68
30
86
40
104
50
122
So, when you reach 50C … well, there are recipes that are called “cooking” that use temperatures in that range.
The 2008 paper found the that we can expect extreme high temperature “values in excess of 50°C in Australia, India, the Middle East, North Africa, the Sahel and equatorial and subtropical South America at the end of the century.” The paper simulates future climate by looking at past and present conditions and factoring in the expected temperature changes from the ECHAM5/MPI-OM climate model which is a combination of the IPCC atmospheric general circulation model (ECHAM5) and MPI-OM ocean-sea ice component developed at the Max Planck Institute for Meteorology. You can read the gory details here (PDF).
That work was done a few years ago, and one of the things I’ve noticed about predictions of future climate change done over the last five or six years is that they are under-estiamtes. If a 2008 paper says Australia will be hitting highs of 50 degrees C by 2095, then based on this heuristic (and it is merely a heuristic but so far one that is working pretty well) you might expect regular extremes higher than 50 degrees C in Oz by 2030 or so. (That uses the Thumsuck Climate Model technique in which we divide all the conservative estimates by three.)
We’ll see. I’m sure that work will be revised and updated soon enough and we’ll have a better model to work with. Meanwhile, climate science denialists are already cooking up a conspiracy theory in which evidence of an extremely warm period in the 19th century was erased by the Australian Scientists and NASA so we would think things are warmer now than today when in fact the warmest period was prior to WW I. Look for that, and laugh, because it is funny. (Not “funny ha ha,” so much. More like “funny, why are they still doing this?”)
So, what has been going on in Australia over the last few months and what is going to happen over the next several days? It’s been hot and it is going to be hot. From the BoM:
Large parts of central and southern Australia are currently under the influence of a persistent and widespread heatwave event. This event is ongoing with further significant records likely to be set. …
The last four months of 2012 were abnormally hot across Australia, and particularly so for maximum (day-time) temperatures. For September to December … the average Australian maximum temperature was the highest on record with a national anomaly of +1.61 °C, slightly ahead of the previous record of 1.60 °C set in 2002 (national records go back to 1910). In this context the current heatwave event extends a four month spell of record hot conditions affecting Australia. These hot conditions have been exacerbated by very dry conditions affecting much of Australia since mid 2012 and a delayed start to a weak Australian monsoon. … The current heatwave event commenced with a build up of extreme heat in the southwest of Western Australia from 25-30 December 2012 … Particularly hot conditions were observed on the 30th, with Cape Naturaliste observing 37.7 °C, its hottest December day in 56 years of record. From 31 December the high pressure system began to shift eastward … Temperatures reached 47.7 °C at Eyre on the 2nd its hottest day in 24 years of record, while Eucla recorded 48.2 °C on the 3rd, its hottest day since records began in 1957. … Hobart experienced a minimum temperature of 23.4 °C on the 4th (its hottest January night on record), followed by a maximum of 41.8 °C (its hottest maximum temperature on record for any month in 130 years of records) and the highest temperature observed anywhere in southern Tasmania.
The report includes the following two figures:
The maximum temperature anomaly from the 1961-1990 average for the last week of December (the start of the heatwave event in Western Australia). Units are °C.The maximum temperature anomaly from the1961-1990 average for January 1 to 6. Units are °C.
According to the most recent news reports, things are pretty hard for people in Australia but there have been few deaths, possibly only one so far, due to heat as yet recorded. This is probably because Australia is in fact a fairly hot and dry country. This is not the same as a heatwave in the Upper Midwest in the US where conditions are different, the population may be more vulnerable, and there are a lot more people per unit area and heat waves often result in dozens, sometimes hundreds, of deaths.
As mentioned in an earlier post, fires have also been an issue in Australia. For example:
Fires are already burning in five states as a search continued for people missing after devastating wildfires in the island state of Tasmania.
Prime Minister Julia Gillard toured Tasmanian townships and promised emergency aid for survivors.
Residents told of a “fireball” that engulfed communities across the thinly-populated state at the weekend.
“The trees just exploded,” local man Ashley Zanol told Australian radio, recounting a wall of flames that surrounded his truck as he carted water to assist fire crews in Murdunna.
SPECIAL CLIMATE STATEMENT 43: Extreme January heat. Last update 7 January, 2013. Climate Information Services. Bureau of Meteorology
Sterl, A., Severijns, C., Dijkstra, H., Hazeleger, W., Jan van Oldenborgh, G., van den Broeke, M., Burgers, G., van den Hurk, B., Jan van Leeuwen, P., & van Velthoven, P. (2008). When can we expect extremely high surface temperatures? Geophysical Research Letters, 35 (14) DOI: 10.1029/2008GL034071
Summer is coming on strong south of the Equator, and in Australia this has meant unprecedented record high temperatures, and in the state of Tasmania, severe brush fires that have destroyed numerous homes, adding to the bad news from fires in the southeastern mainland. Prime Minister Julia Gillard said “And while you would not put any one event down to climate change … we do know that over time as a result of climate change we are going to see more extreme weather events.” That is not exactly true, of course. There are no climate related events that lack the fingerprint of global climate change. Certain events would have occurred in some for or another in the absence of climate change but the chance of any given event is increased, and the potential severity of every single event is increased because of the Earth’s increased temperature from the human release of fossil Carbon into the atmosphere and other related causes.
My colleague Stephan Lewandowsky, of the University of Western Australia just sent me these observations, which have not yet been made public but will be verified shortly: “Never before in recorded history has Australia experienced 5 consecutive days of national-average maximum temperatures above 39C. Until today. And this heat is expected to continue for another 24-48 hours, extending the new record run to 6 or even 7 days. For context, the previous record of 4 days occurred once only (1973) and 3 days has occurred only twice (1972,2002).”
Here’s a map of the temperatures country wide yesterday:
Top “Ten” Recent Books (focusing on 2012 but including the last few years) on Climate, Science denialism, Energy, and Science Policy are (including one Post Warming novel) are:
A group of us, all interested in climate science, put together a list of the most notable, often, most worrying, climate-related stories of the year, along with a few links that will allow you to explore the stories in more detail. We did not try to make this a “top ten” list, because it is rather silly to fit the news, or the science, or the stuff the Earth does in a given year into an arbitrary number of events. (What if we had 12 fingers, and “10” was equal to 6+6? Then there would always be 12 things, not 10, on everyone’s list. Makes no sense.) We ended up with 18 items, but note that some of these things are related to each other in a way that would allow us to lump them or split them in different ways. See this post by Joe Romm for a more integrated approach to the year’s events. Also, see what Jeff Masters did here. We only included one non-climate (but related) item to illustrate the larger number of social, cultural, and political things that happened this year. For instance, because of some of the things on this list, Americans are more likely than they were in previous years to accept the possibility that science has something to say about the Earth’s climate and the changes we have experienced or that may be in the future; journalists are starting to take a new look at their own misplaced “objective” stance as well. Also, more politicians are starting to run for office on a pro-science pro-environment platform than has been the case for quite some time.
A failing of this list is that although non-US based people contributed, and it is somewhat global in its scope, it is a bit American based. This is partly because a few of the big stories happened here this year, but also, because the underlying theme really is the realization that climate change is not something of the future, but rather, something of the present, and key lessons learned in that important area of study happened in the American West (fires) the South and Midwest (droughts, crop failures, closing of river ways) and Northeast (Sandy). But many of the items listed here were indeed global, such as extreme heat and extreme cold caused by meteorological changes linked to warming, and of course, drought is widespread.
This list is subject to change, because you are welcome to add suggestions for other stories or for links pertaining to those already listed. Also, the year is not over yet. Anything can happen in the next few days!
Super Storm Sandy, a hybrid of Hurricane Sandy (and very much a true hurricane up to and beyond its landfall in the Greater New York/New Jersey area) was an important event for several reasons. First, the size and strength of the storm bore the hallmarks of global warming enhancement. Second, its very unusual trajectory was caused by a climatic configuration that was almost certainly the result of global warming. The storm would likely not have been as big and powerful as it was, nor would it have likely struck land where it did were it not for the extra greenhouse gasses released by humans over the last century and a half or so.
A third reason Sandy was important is the high storm surge that caused unprecedented and deadly flooding in New York and New Jersey. This surge was made worse by significant global warming caused sea level rise. Sea level rise has been eating away at the coasts for years and has probably caused a lot of flooding that otherwise would not have happened, but this is the first time a major event widely noticed by the mainstream media (even FOX news) involving sea level rise killed a lot of people and did a lot of damage. Fourth, Sandy was an event, but Sandy might also be the “type specimen” for a new kind of storm. It is almost certainly true that global warming Enhanced storms like Sandy will occur more frequently in the future than in the past, but how much more often is not yet known. We will probably have to find out the hard way.
Note that the first few of the links below are to blog posts written by concerned climate scientists, whom the climate change denialists call “alarmists.” You will note that these scientists and writers were saying alarming things as the storm approached. You will also note that what actually happened when Sandy struck was much worse than any of these “alarmists” predicted in one way or another, in some cases, in several ways. This then, is the fifth reason that Sandy is important: The Earth’s weather system (quite unconsciously of course) opened a big huge can of “I told you so” on the climate science denialist world. Sandy washed away many lives, a great deal of property and quite a bit of shoreline. Sandy also washed away a huge portion of what remained of the credibility of the climate science denialist lobby.
3 The Polar Ice Caps and other ice features experienced extreme melting this year.
This year, Arctic sea ice reached a minimum in both extent (how much of the sea is covered during the Arctic summer) and more importantly, total ice volume, reaching the lowest levels in recorded history.
We also increasingly recognized that loss of Arctic sea ice affects Northern Hemisphere weather patterns, including severe cold outbreaks and storm tracks. This sea ice loss is what set up the weather pattern mentioned above that steered Sandy into the US Northeast, as well as extreme cold last winter in other areas.
5 and 6 Two major melting events happened in Greenland this summer.
First, the total amount of ice that has melted off this huge continental glacier reached a record high, with evidence that the rate of melting is not only high, but much higher than predicted or expected. This is especially worrying because the models climatologists use to predict ice melting are being proven too optimistic. Second, and less important but still rather spectacular, was the melting of virtually every square inch of the surface of this ice sheet over a short period of a few days during the hottest part of the summer, a phenomenon observed every few hundred years but nevertheless an ominous event considering that it happened just as the aforementioned record ice mass loss was being observed and measured.
…were formed when the Petermann Glacier of northern Greenland calved a massive piece of its floating tongue, and it is likely that the Pine Island Glacier (West Antarctica) will follow suit this Southern Hemisphere summer. Also, this information is just being reported and we await further evaluation. As summer begins to develop in the Southern Hemisphere, there may be record warmth there in Antarctica. That story will likely be part of next year’s roundup of climate-related woes.
8 More Greenhouse Gasses than Ever
Even though the rate of emissions of greenhouse gasses slowed down temporarily for some regions of the world, those gasses stay in the air after they are released, so this year greenhouse gas levels reached new record high levels
As expected, given the greenhouse gases just mentioned, Record Breaking High Temperatures Continue, 2012 is one of the warmest years since the Age of the Dinosaurs. We’ll wait until the year is totally over to give you a rank, but it is very, very high.
A very rare event caused by drought conditions was the closing of the Mississippi River to traffic in mid-summer at two locations. This is part of a larger and growing problem involving drought, increased demands for water, and the importance of river traffic. Expect to hear more about this over the next couple of years.
In June, a major and very scary derecho event – a thunderstorm and tornado complex large enough to get its own Wikipedia entry – swept across the country. This was one of several large storm systems that caused damage and death in the US this year. There were also large and unprecedented sandstorms in Asia and the US.
We continue to experience, and this will get worse, great Losses in Biodiversity especially in Oceans, much of that due to increased acidification because of the absorption of CO2 in seawater, and overfishing.
18 Unusual Jet Stream Configuration and related changes to general climate patterns…
Many of us who contributed to this list feel that this is potentially the most important of all of the stories, partly because it ties together several other events. Also, it may be that a change in the air currents caused by global warming represents a fundamental yet poorly understood shift in climate patterns. The steering of Hurricane Sandy into the New York and New Jersey metro areas, the extreme killer cold in Eastern Europe and Russia, the “year without a Spring” and the very mild winters, some of the features of drought, and other effects may be “the new normal” owing to a basic shift in how air currents are set up in a high-CO2 world. This December, as we compile this list, this effect has caused extreme cold in Eastern Europe and Russia as well as floods in the UK and unusually warm conditions in France. As of this writing well over 200 people have died in the Ukraine, Poland and Russia from cold conditions. As an ongoing and developing story we are including it provisionally on this list. Two blog posts from midyear of 2011 and 2012 (this one and this one) cover some of this.
The following video provides an excellent overview of this problem:
19 The first climate denial “think” tank to implode as a result of global warming…
… suffered major damage this year. The Heartland Institute, which worked for many years to prove that cigarette smoking was not bad for you, got caught red handed trying to fund an effort explicitly (but secretly) designed to damage science education in public schools. Once caught, they tried to distract attention by equating people who thought the climate science on global warming is based on facts and is not a fraud with well-known serial killers, using large ugly billboards. A large number of Heartland Institute donors backed off after this fiasco and their credibility tanked in the basement. As a result, the Heartland Institute, which never was really that big, is now no longer a factor in the climate change discussion. We failed to drive the wooden stake through Heartland’s heart when it was down. While Heartland has lost much of their funding and Corporate support Hearthland’s Anti-Science Syndrome Hatred Of a Livable Economic System voices still get soapboxes in traditional media =91balance=92 articles and otherwise. Learning how to pound in the wooden stake has merit.
The IPCC, as you know, comes out with a set of reports every five years. The reports are written by groups of experts. Draft reports are widely accessible to people who register themselves as “experts” and there is no quality control in that process, in order to keep things as transparent as possible. This means that the worst climate change denialists can simply sign up as “experts” and flood the scientists trying to write these reports with irrelevant and stupid comments, thus, I presume, wasting valuable time and effort. But, such is the cost of transparency, which is important.
But, even the climate change denailits, who tend to be a rowdy group with with only a vague grasp, if any, on ethics and who generally have very little respect for truth, have to promise to not release any part of the draft that they have had the privilege to see and comment on. This is very important for reasons that are so blindingly obvious I won’t bother explaining them here.
Well, over the last few days, one of the denialsts, in comments on one of the famous denialist blogs, released sections of the report. The part he released, essentially, said:
“There is this idea X which suggests that Y happens. There is no evidence that this is true but we looked carefully at it and there is still no evidence that this is true.”
But by cherry picking and providing a lie as context, the climate change science denier (CCSD) made it say:
“There is t his idea X which suggests that Y happens. Y means global warming is not real. This is in the ICPP report. This is a game changer.”
Below I’m going to give you links to a handful of the blog posts out there that explain exactly what happened, as well as a document just released by the IPCC expressing regret that one of the “expert reviewers” did this thing that should not have been done.
I wonder if that person’s “expert” status will remain in place. It probably should. The whinging and moaning that would result from someone violating the rules being tossed out, from the CCSD afflicted community, would be more annoying than letting the jerk continue to pretend that he is an “expert” on something.
There are these things called “Atmospheric rivers.” They are big long things up in the air that are loaded with water vapor, and much of the rain and other precipitation we experience comes out of them. This is notable when one of these rivers is extra wet, and there is an extra wet one out West in the US.
The Sierra Nevada range will be accumulating something like 16-20 inches of rain, but where that translates into snow, it will be up there in the 12 foot range, maybe more. There will be a very significant risk of flash flooding north of Sacremento and places in northern California and Oregon are going to get very very wet. The Bay Area will see lots of rain but mostly to the north, in Marin County.
A significant rainfall event is underway across portions of the West Coast as unrelenting Pacific moisture slams into the region. Northern California and southern Oregon will see the greatest rainfall totals of 10 to 20 inches by early next week. Strong winds and mountain snow will also impact the area.
The reason I mention this at all (those of you who live there, I’m sure, are totally up on this) is the following: This sort of excess rain is exactly what we expect to see more often because of global warming. This is the effect that global warming has on the hydrological cycle. It fills the Atmospheric Rivers with more moisture than would otherwise develop in them.
PASADENA, Calif. – An international team of experts supported by NASA and the European Space Agency (ESA) has combined data from multiple satellites and aircraft to produce the most comprehensive and accurate assessment to date of ice sheet losses in Greenland and Antarctica and their contributions to sea level rise.
In a landmark study published Thursday in the journal Science, 47 researchers from 26 laboratories report the combined rate of melting for the ice sheets covering Greenland and Antarctica has increased during the last 20 years. Together, these ice sheets are losing more than three times as much ice each year (equivalent to sea level rise of 0.04 inches or 0.95 millimeters) as they were in the 1990s (equivalent to 0.01 inches or 0.27 millimeters). About two-thirds of the loss is coming from Greenland, with the rest from Antarctica.
From the abstract of the paper:
We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth’s polar ice sheets. We find that there is good agreement between different satellite methods—especially in Greenland and West Antarctica—and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by –142 ± 49, +14 ± 43, –65 ± 26, and –20 ± 14 gigatonnes year?1, respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year?1 to the rate of global sea-level rise.
The melting since about 1992 to the present has contributed to about 0.44 inches of sea level rise (about a fifth of the sea level rise over that period, and there was sea level rise prior to 1992 as well). The main outcome of this study is to clean up the predictions from previous models with much better data and to narrow down the best predictions for future melting. Also, the pace of ice loss now is greater than it was at the beginning of the study period, 20 years ago. Greenland is losing ice about 500% faster now than it was in the early 1990s, while Antarctica is losing ice at about the same rate now as it was then.
Shepherd, A., Ivins, E., A, G., Barletta, V., Bentley, M., Bettadpur, S., Briggs, K., Bromwich, D., Forsberg, R., Galin, N., Horwath, M., Jacobs, S., Joughin, I., King, M., Lenaerts, J., Li, J., Ligtenberg, S., Luckman, A., Luthcke, S., McMillan, M., Meister, R., Milne, G., Mouginot, J., Muir, A., Nicolas, J., Paden, J., Payne, A., Pritchard, H., Rignot, E., Rott, H., Sorensen, L., Scambos, T., Scheuchl, B., Schrama, E., Smith, B., Sundal, A., van Angelen, J., van de Berg, W., van den Broeke, M., Vaughan, D., Velicogna, I., Wahr, J., Whitehouse, P., Wingham, D., Yi, D., Young, D., & Zwally, H. (2012). A Reconciled Estimate of Ice-Sheet Mass Balance Science, 338 (6111), 1183-1189 DOI: 10.1126/science.1228102
Photo of icebergs in Disko Bay, Greenland from NASA
Despite the fact that the word “Dinosaurs” occurs in the title, this book is only partly about dinosaurs. In fact, I would say it is mostly about mammals, insofar as the critters go. And that’s good because Donald Prothero is probably the world’s leading expert on Fossil Mammals. The dinosaur part is major and interesting, though. One of the mysteries Don addresses is the presence of Dinosaurs in the region of the earth that is dark for 6 months out of the year and generally frozen. Indeed, the “greenhouse effect” was very much stronger (in that there were more greenhouse gasses) in those days than today. All that atmospheric Carbon (in the form of CO2) was eventually to be trapped in the lithosphere, which helped cause the planet to cool to the levels that were around when we, as a species (genus, really) evolved. The world in which everything alive today evolved in is a world with a few hundred parts per million of CO2 in the atmosphere, the world of the “Dino Greenhouse” had much more CO2, and we are quickly heading back to the Dinosaur era level, which is going to really mess us up.
Greenhouse of the Dinosaurs: Evolution, Extinction, and the Future of Our Planet addresses questions of “Yeah, so, it was hot then and everything was fine, so Global Warming is not important.” Don also regales the reader with stories about doing palaeontology, about controversies in the field, and that sort of thing. And, he brings us past the K-T boundary, to the “Cainozoic” (age of “Cain) during which the earth cooled, and mammals took over to be the dominant large visible above ground life form. (Yes, yes, I know, bacteria are the dominant life form, yadda yadda… just don’t look for any murals of bacteria interacting on the wall of the Yale Peabody Musuem any time soon.)
Climate Denial Crock of the Week gives us this new video. Details here.
We are not yet where we need to be with this “when did you stop beating your wife” question sometimes in the form of:
“Can you REALLY attribute ANY storm to Global Warming, really? No? Then is global warming really real? Really?”)
Next time someone says something like that to you, consider answering the question with a question:
“Which major storm of the last two decades or so did not include any of the extra climatic energy provided to this planet by the release of fossil Carbon and other greenhouse gasses into the atmosphere by human activities? WHICH ONES, DAMMIT!?!??”
This is temperature increasing on the earth over a century or so. Notice that there is what looks like a warming around 1940 on top of an otherwise mostly warming trend, followed by a bunch more warming.
The Fourth Assessment Report of the IPCC, in 2007, referring to data that ran up to 2005 inclusively, said the following:
Most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.
Later, in a congressional hearing, Patrick Michaels, a climate science denialist (one of the meteorologists famous for his rejection of the data and science demonstrating a human induced warming trend) said to a congressional committee, of the statement by the IPCC:
… greenhouse-related warming is clearly below the mean of relevant forecasts by IPCC … the Finding of Endangerment from greenhouse gases by the Environmental Protection Agency is based on a very dubious and
critical assumption.
A probabilistic quanti?cation of the anthropogenic component of twentieth century global warming examines both claims and concludes that Michaels is wrong. From the abstract:
This paper examines in detail the statement in the 2007 IPCC Fourth Assessment Report that “Most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” We use a quantitative probabilistic analysis to evaluate this IPCC statement, and discuss the value of the statement in the policy context. For forcing by greenhouse gases (GHGs) only, we show that there is a greater than 90% probability that the expected warming over 1950–2005 is larger than the total amount (not just ‘‘most’’) of the observed warming. This is because, following current best estimates, negative aerosol forcing has substantially offset the GHG-induced warming. We also consider the expected warming from all anthropogenic forcings using the same probabilistic framework. This requires a re-assessment of the range of possible values for aerosol forcing. We provide evidence that the IPCC estimate for the upper bound of indirect aerosol forcing is almost certainly too high. Our results show that the expected warming due to all human in?uences since 1950 (including aerosol effects) is very similar to the observed warming. Including the effects of natural external forcing factors has a relatively small impact on our 1950–2005 results, but improves the correspondence between model and observations over 1900–2005. Over the longer period, however, externally forced changes are insuf?cient to explain the early twentieth century warming. We suggest that changes in the formation rate of North Atlantic Deep Water may have been a signi?cant contributing factor.
Not only is the IPCC assessment correct according to this new paper, but it is a bit of an understatement.
So much for that little bit of climate science denialism.
Wigley, T., & Santer, B. (2012). A probabilistic quantification of the anthropogenic component of twentieth century global warming Climate Dynamics DOI: 10.1007/s00382-012-1585-8
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