…Sixty easy-to-read entries tackle such questions as: Is climate ever “normal”? Why and how do fossil-fuel burning and other human practices produce greenhouse gases? What natural forces have caused climate change in the past? What risks does climate change pose for human health? What accounts for the diminishment of mountain glaciers and small ice caps around the world since 1850? What are the economic costs and benefits of reducing carbon emissions?
Robert Krulwich at NPR pulled a nice graphic out of the book to exemplify one of the topics covered. Have a look:
The reason for the longer frost free periods is primarily increased warmth at night, when the last and first frosts tend to happen. This, in turn, is the result of an atmosphere that holds more of the heat that would normally radiate out into space. This was predicted, it happened, and there you go.
Warning: This graph should not be used for developing your own local gardening plans. The lengthening of the frost free season is highly dependent on geography. Your mileage will vary.
There is a relationship between how much CO2 is in the atmosphere and sea level. More CO2 means a warmer atmosphere and that means less long term (glacial) ice and that means more sea water. Also, a warmer planet means the ocean water is warmer, and thus it expands, and that also contributes to sea level rise.
However, there is something of a falsehood generated when we read estimates of sea level rise. The straight forward link between CO2 and sea level (via heating oceans and melting ice) leads to estimates that are very small for sea level rise. We see things like “1.8 mm per year” which would be a very small number that does not seem like much of a threat. This is a falsehood for several reasons. The variation in sea level linked to a given level of CO2 is potentially great, in the order of meters; one level of CO2 could produce a wide range of sea levels, with a range of variation way bigger than the total sea level rise with annual increments like 1.8 mm. Sea level rise of seemingly small amounts, i.e. several centimeters, produce lateral (transgressive) shifts in the sea of potentially much greater amounts. This transgression can be fast, or it can be longer term. We are still experiencing the transgression from the post-glacial sea level rise that slowed to nearly a halt thousands of years ago. Meanwhile, coastal storms can be much more likely to flood inland with higher seas. All this means that the time scale of effects varies from days (storms) to decades (barrier beach erosion) to centuries (erosion against more stable coastal areas made of consolidated sediment) to millennia (erosion of major glacial features) to time periods that transcend climate change (erosion of continental bedrock). The scale of past sea level change is enormous, larger than any possible future sea level rise, but the “worst case” scenarios for the future are both dramatic and not all that unlikely. All this comes from taking a paleo-perspective on sea level change. In short, when we paleo-people hear estimates of a few millimeters a year of sea level rise over a century’s time, we laugh. Nervously.
Meanwhile, here is the list of the other amazing and wonderful blog posts that make up this Blogathon so far. I’ll update it to include all the posts later:
You all know about CONvergence, and by now you’ve probably heard about or even seen or heard on the Internet one or more of the many panels that were done this year. But those recordings were impromptu and while useful, they are unpolished.
Also, the panels at CONvergence themselves tend to be informal, unmoderated or moderated by helpful volunteers, and everyone has a hangover. People attending the panels drew on important expertise and experience, but most panels were casual, with little preparation.
But a couple of the panels were different, most notably two panels on Climate Change. These panels were designated early on in the CONvergence planning as being key, and a lot of attention was given to them. The panelists were all experienced speakers on the topic and knew long in advance what the topic of discussion would be. Most of us communicate on a daily basis about climate change related issues, and have known each other and worked with each other on science communication for the last few years. Desiree Schell was flown down from Canada to moderate the panels. I spent a fair amount of effort outlining possible topics and running this outline past the panelists for their contribution, and we passed this information on to Desiree, who then worked out an interview and moderation plan. In other words, more hours of work were spent in the background prior to the panels than the two hours of public discussion that they turned into.
Then, we had two hours of panel discussion and questions from the audience. Professional level equipment was used to record the panels.
THEN, KO Myers, the producer of Skeptically Speaking, took this two hours of panel discussion and locked himself in the studio with it and converted or senseless yammering it into a final finished product of the highest quality.
And all this was done for you, dear reader, so that you could learn all about climate change.
We are becoming aware of two very important changes in the Arctic that you need to know about. These are separate thing but related, and both are almost certainly the outcome of anthropogenic global warming (AGW). They are:
The sea ice that covers much of the Arctic Sea during the winter is normally reduced during the northern summer, but this year, the reduction has been dramatic. There is less sea ice in the Arctic Circle than recorded in recent history.
The massive continental glacier on Greenland, the largest glacial mass in the Northern Hemisphere, has undergone more melting this summer than observed over recent years. A few weeks ago you may have heard about a great melt in Greenland. This is not that. The July Melting event was interesting and I’ll discuss it below, but the news story breaking today is about something else.
The Arctic Sea Ice
Every summer the large areas of the Arctic Sea’s ice melts away, then it refreezes each winter. The minimum extent of ice is typically reached in about mid September. The extent of ice at this minimum has been getting steadily less over time. Direct and accurate measurements don’t go back far enough to track the effects of AGW over the entire time this has been happening, but we can pretty easily look at the last few decades. Have a look at this graph:
The Arctic Sea Ice appears to be reduced more this year than at any time in recent history.
Note that the total amount of sea ice in an average year in the 2000’s decade is about one third less than the total amount of ice in the 1980s, at the minimum period in September. Below the 2000’s line are plotted the three most ice-free years in the dataset; those are the extreme years. The present year, 2012, is tracked through mid-August on this graph.
The present year, 2012, is on track for breaking all records for the Arctic Sea ice minimum.
Here’s an interesting side story. Notice how the red line for 2012 is much straighter in a downward direction than the other lines for the same time period for the last several days of measurement. My understanding is that large storms in the Arctic appeared, covering the sea ice from observation for several days, and when the storms cleared a whole bunch of the ice was gone. This is not that unusual. Storms hasten the disappearance of sea ice. But this was a more dramatic than typical example of this event.
In case you were wondering if it was storminess and not AGW that is causing this year’s ice to be less than the other years, and I’m sure that climate change deniers will make this claim, keep in mind that a) this recent storminess does not explain more than a small amount of the ice reduction compared to overall melting and b) AGW has caused there to be more storminess in the Arctic and more warmth in the Arctic.
The Greenland Melt-off of July
Before getting to the really big news from Greenland, I want to first remind you of an interesting event that happened in July, reported by NASA (I mentioned it here). Every summer, some of the ice melts on the surface of Greenland’s massive glacier, then much of that refreezes. However, the melting is usually spotty…here and there and rarely everywhere. The highlands are too cold to melt at all in some years. But July was very warm and there were a few days when virtually the entire surface of greenland melted. There were slushy puddles everywhere. Then, much of it refroze. This happens now and then. We can assume that widespread melting like this is more common in a warmer world, and will be part of the process of glacial wasting as the Greenland Ice Sheet turns over time into seawater. But this particular event was in and of itself not entirely unheard of.
But there is a neat graph that shows why glacial melting is both more important than one might thing and also more complicated than one might think. Have a look: The lower the albedo, the more the warming. And visa versa.
Just as sea ice extent in the Arctic reduces every summer, the albedo of the Greenland Ice sheet reduces. The white fresh frozen snow that falls over the winter is highly reflective…has a high albedo…and as it melts and gets slushy and mixes with water is has lower albedo. Plain water has very low albedo compared to snow. This is important because high albedo surfaces reflect a lot of sunlight (which provides heat) back into space while low albedo surfaces absorb sunlight, converting it to heat that adds to the local and ultimately global temperature.
There is a feedback mechanism at work here. Imagine that something happens to make for a late Canadian winter with a widespread heavy snow storms much later than usual. This could be caused by a combination of events happening just right in a given year. So, late in the spring there is a lot more snow cover than normal. This snow will reflect a lot of sunlight away so the beginning of the summer is cooler. If this effect lasts into fall, early snows may cause the subsequent winter to be even colder and snow to fall instead of rain, producing more Albedo. Etc. Conversely, something that reduces albedo in a given year may cause more melting of snow and ice, which means less albedo, and thus more melting. You get the picture.
In the days before we understood Orbital Geometry and before we had a very good ida of how air and sea currents really work, this feedback effect with albedo was considered as a candidate for what causes glacial periods to come on and go away. We now know that albedo related forcing and feedback is not the prime mover in climate change, but it is still an effect.
In the graph above, you see the line for the present year. Note that Greenland albedo is lower for the entire year than for any of the other years plotted. Then, in July, that melting event occurs. Then, the water freezes. Albedo is not like sea ice extent (compare to the two graphs). Sea ice extent is a slowly changing ponderous slow moving variable, while Albedo is al wiggly-wobbly and highly variable. A big snow storm, albedo goes up. A big rain storm, albedo goes down. So, the wobbliness of the line does not mean too much, but it is very cool to see the direct relationship between observed widespread melting and albedo. And, this effect will probably play a role as the Greenland Ice Sheet melts away.
And now, for the big news
The really big new that is coming out today is about greenland. From a press release covering the findings of Mardo Tedesco, professor of Earth and atmospheric sciences at The City College of New York:
Melting over the Greenland ice sheet shattered the seasonal record on August 8 – a full four weeks before the close of the melting season…
This year, cumulative melting in the first week in August had already exceeded the record of 2010, taken over a full season
“With more yet to come in August, this year’s overall melting will fall way above the old records. That’s a goliath year – the greatest melt since satellite recording began in 1979.” …
This spells a change for the face of southern Greenland, he added, with the ice sheet thinning at its edges and lakes on top of glaciers proliferating.
Professor Tedesco noted that these changes jibe with what most of the models predict – the difference is how quickly this seems to be happening.
To quantify the changes, he calculated the duration and extent of melting throughout the season across the whole ice sheet, using data collected by microwave satellite sensors.
This ‘cumulative melting index’ can be seen as a measure of the ‘strength’ of the melting season: the higher the index, the more melting has occurred.
…
This year, Greenland experienced extreme melting in nearly every region – the west, northwest and northeast of the continent – but especially at high elevations. In most years, the ice and snow at high elevations in southern Greenland melt for a few days at most. This year it has already gone on for two months.
Here’s the graph showing the relative amount of ice melt per year in Greenland for the last few decades.
More ice had melted off of the Greenland Glacier by August 8th than in any full year of measurements in recent decades.
I’d like to give you a very small selection of references and discussions about the link between global warming and drought.
Global warming probably has two major effects. First, more moisture gets into the atmosphere because warmer air passing over the oceans can take in more water. This can cause more rain and possibly more severe storms and flooding. But the atmospheric system also changes in another way. The hydraulic cycle, as it is called, intensified in both directions, wet and dry. If you live on the East Coast of the US and you move to where I live in the upper Midwest, you’ll get a special appreciation of this. Rain on the East Coast comes in thunderstorms now and then, but a lot of the rain comes from big wet air masses linked to the ocean. In Boston it can rain for a few days off and on but mostly on, with an inch off rain falling over a long period of time. But here in the Midwest, that almost never happens. Instead, it’s not raining, then this big scary storm comes and dumps a whole pile of rain on you, then it moves on. In between storms it can be dry vor many days. The Midwestern storms come from warm air masses passing over the Gulf of Mexico and moving north (then turning “right” at some point) with contributions from elsewhere. It is more intensified hydrological system, with a lot of variation. That is a min-model (albeit a pretty inexact one) for shifting to a warmer planet. Keep in mind that between rain storms, warmer air takes moisture out of the local system (to dump it in a storm somewhere else). Climate experts generally agree that a warmer world will have more severe storms, though which storms will be more severe and in what way is not clear, and drought. Lots of that. Continue reading What is the link between global warming and drought?→
The worst drought in a long time, which is a result of anthropogenic global warming, has caused barges to run aground in Arkansas and Wisconsin shutting down barge traffic at those two points along the enormous inland waterway.
It was unclear when the key shipping waterway might be reopened to commercial traffic…
Low water has restricted barge drafts to a lighter-than-normal nine feet and limited barge tows to fewer barges on numerous sections of the Mississippi River.
But even as vessels have lightened their cargo loads, numerous boats have run aground in recent weeks, forcing temporary river closures and snarling north- and southbound freight traffic. The river is a major shipping lane for grains, oilseeds, fertilizer, salt, coal, and other cargo.
This video looks at the scientific research to answer three basic questions: 1) Was the Medieval Warm Period global? 2) Was it warmer than today? 3) And what does this all mean anyway? I examine the internet feud over the hockey stick and the various myths and misinterpretations about the Medieval Warm Period that seem to be rife on the Internet. My sources for the myths are blogs and videos; my sources for the facts are scientific papers.
I have always felt that sea level rise would be quicker and higher than my colleagues in climate science have suggested. My reasoning for that is simple. Sea level rise has in the past not followed overall climate change in a perfectly simple manner such that the present era has lower sea levels than it should. When this was noticed in the mid 20th century up through the 1970s, in the form of high wave cut benches along various rocky shore lines, the explanations usually invoked moving land masses, such as a continent buoying upwards as it eroded, so the same sea level would cut benches that were higher and higher the farther back in time you go. And, that probably happens to some extent. But it turns out that the amount of ice trapped in continental glaciers in the northern and southern hemispheres is probably more than it “should” be given current conditions.
Joe Romm of Climate Progress gave testimony to the US Congress on the relationship between the release of long-trapped Carbon into the atmosphere through the use of fossil fuels and drying conditions that lead to an increase in wild fires. Joe notes “… we’re already topping Dust Bowl temperatures in many places — and the Earth has warmed only about 1 degree Fahrenheit since the 1930s Dust Bowl. Yet we are poised to warm some 10 degree Fahrenheit this century if we stay on our current path of unrestricted carbon pollution emissions.”
We probably are having the warmest year ever recorded by science, and one of the warmest years in a couple/few hundred thousand years as recorded by proxyindicators. Bill’s piece talks about three “terrifying” numbers: 2 degreec Celsius, 565 Gigatons, and 2795 Gigatons.
And there are other numbers too:
…The week after the Rio conference limped to its conclusion, Arctic sea ice hit the lowest level ever recorded for that date. Last month…Tropical Storm Debby dumped more than 20 inches of rain on Florida – the earliest the season’s fourth-named cyclone has ever arrived. …the largest fire in New Mexico history burned on, and the most destructive fire in Colorado’s annals claimed 346 homes in Colorado Springs – breaking a record set the week before in Fort Collins. …scientists issued a new study concluding that global warming has dramatically increased the likelihood of severe heat and drought – days after a heat wave across the Plains and Midwest broke records that had stood since the Dust Bowl, threatening this year’s harvest….In the course of this month, a quadrillion kernels of corn need to pollinate across the grain belt, something they can’t do if temperatures remain off the charts.
We expected increasing wildfire activity with global warming, and we’ve got it.
The Waldo Canyon Fire has been burning since June 23rd and as of this writing is essentially out of control, with about 5% of it “contained.” Tens of thousands of people have been evacuated. A friend of mine is on house watch as we speak, as various members of her family and her friends from the region have fled the area and are scanning news images for evidence of anything standing (or not) in their neighborhood. Approximately 300 homes are reported to have been burned down yesterday, I have not herd any reports from today. Continue reading Waldo Canyon and Other Colorado Fires→
Peter Gleick has been cleared of faking a key memo. Who is Peter Gleick, and what is this memo of which we speak? Here is a refresher of events over the last 3 1/2 months:
You will recall that last February 14th, we were all given an interesting Valentine’s Day present: A cache of documents had been acquired from the Heartland Institute, and these documents revealed important details about Heartland’s effort to interfere with science education and otherwise agitate and lobby to promote climate science denialism. The documents were released to the public by an as then unknown activist, and then redistributed by numerous bloggers including this one.
Heartland is the organization that made itself famous by working for the tobacco lobby in their effort to prove that smoking cigarettes was not really harmful. Over recent years, Heartland has received funds from a wide range of organizations and individuals to support climate denialism. Most recently, Heartland gained considerable notoriety (the bad kind) with their noxious and ill-conceived billboard campaign that equated “believing in global warming” with being a deranged serial killer (Tool Time: Heartland, Ted Kaczynski, and Education).
Diageo announces it is to end funding of Heartland Institute
Diageo, one the world’s largest drinks companies, has announced it will no longer fund the Heartland Institute, a rightwing US thinktank which briefly ran a billboard campaign this week comparing people concerned about climate change to mass murderers and terrorists, such as Osama bin Laden, Charles Manson and Ted Kaczynski.
On Thursday, a billboard appeared over the Eisenhower Expressway in Illinois showing a picture of Ted Kaczynski, the Unabomber who in 1996 was convicted of a 17-year mail bombing campaign that killed three people and injured dozens. The caption read: “I still believe in global warming. Do you?” A day later it was withdrawn.
As is the case with most things that are important, we as a society have done a very bad job of developing an effective conversation about Global Warming. The vast majority of electronic and real ink that I see spent on the discussion of Global Warming (outside of the peer reviewed literature) is not even about climate or climate change. Rather, it is about talking about climate change, the politics of climate change, critique of the rhetoric about climate change, clarification, obfuscation, complaining, accusing, yelling or belly-aching, and the occasional threat of violence. And today, dear reader, I’d like to give you some more of that! (Well, some of it. There will be no threats!)
