Climate Progress: An insider's view of climate science, politics, and solutions

Earth has done an ecological about-face: Global plant productivity that once flourished under warming temperatures and a lengthened growing season is now on the decline, struck by the stress of drought.

NASA-funded researchers Maosheng Zhao and Steven Running, of the University of Montana in Missoula, discovered the global shift during an analysis of NASA satellite data. Compared with a six-percent increase spanning two earlier decades, the recent ten-year decline is slight — just one percent. The shift, however, could impact food security, biofuels, and the global carbon cycle.

“We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested that global warming might actually help plant growth around the world,” Running said.

“These results are extraordinarily significant because they show that the global net effect of climatic warming on the productivity of terrestrial vegetation need not be positive — as was documented for the 1980’s and 1990’s,” said Diane Wickland, of NASA Headquarters and manager of NASA’s Terrestrial Ecology research program.

That’s from a remarkable NASA news release today, “Drought Drives Decade-Long Decline in Plant Growth” (see narrated video below).

On Friday, the journal Science publishes the study itself, ” Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009” (subs. req’d), which found:

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Last week, the anti-science crowd were touting a couple of statisticians who had launched a slashing cross-check on a small portion of the scientific research supporting  our scientific understanding that current warming is very likely unprecedented in the last thousand years.

As I discussed here, the McShane and Wyner analysis actually produced a Hockey Stick — and even as the climate science community ducked the blow, the Medieval Warm Period got hit in the head (see also Deltoid, who spruced up their graph):

But wait, the anti-science disinformers say,  you left out the part of their analysis where they call into question all such graphs.  And that was because I am on vacation and was waiting for the refs who I knew were busy  reviewing the tapes  before making their penalty call.  In short, I knew that part of the analysis was deeply flawed.

I have been told that when McShane and Wyner is actually  published it will be accompanied by several commentaries.  I  am confident they will identify rather significant shortcomings in the paper.  So  you may surmise that one reason you haven’t seen more definitive debunkings to date is that some people are holding off until those commentaries are published.

But in the meantime, you can read an evisceration of their analysis by Deep Climate –  a terrific climate science blogger known for uncovering details of just how some of the most fraudulent charges against Mann and the Hockey Stick graph were trumped up by the anti-science crowd in the first place.

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Our favorite climate de-crocker, Peter Sinclair has a new video that features someone who may be smarter than all the other anti-science disinformers [combined?]:

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Physicist John Cook of Skeptical Science has a good piece on “The significance of the CO2 lag” that I’m reposting here, followed by a discussion of the best-studied feedbacks and their likely impact (with links to the literature).

When we examine past climate change using ice cores, we observe that CO2 lags temperature. In other words, a change in temperature causes changes in atmospheric CO2. This is due to various processes such as warmer temperatures causing the oceans to release CO2. This has lead some to argue that the CO2 lag disproves the warming effect of CO2. However, this line of thinking doesn’t take in the full body of evidence. We have many lines of empirical evidence that CO2 traps heat. Decades of lab experiments reveal how CO2 absorbs and scatters infrared radiation. Satellite measurements find CO2 trapping heat and surface measurements confirm more radiation at CO2 wavelengths returning to the Earth’s surface. So the full body of evidence gives us these two facts: warming causes more CO2 and more CO2 causes warming. The significance should by now be obvious. The CO2 lag is evidence of a climate positive feedback.

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Before we begin the investigation into the usual suspects, some background for people who those who don’t follow climate science closely, which certainly includes most of the disinformers and  apparently at least two statisticians.

1. There is a high probability that the recent warming is unprecedented for 1000 years and probably much longer (see “Sorry disinformers, hockey stick gets longer, stronger: Earth hotter now than in past 2,000 years“ and here and here).
2. This conclusion is based on an analysis of multiple proxies for temperature, which individually engender much uncertainty and collectively still engender a fair amount.  It is a canard of Curry-esque proportions to assert that scientists have not clearly explained the nature and extent of these uncertainties. They have bent over backwards to do so.
3. The temperature trend in the past millennium prior to about 1850 is well explained in the scientific literature as primarily due to changes in the solar forcing along with the effect of volcanoes, whereas the recent rise in temperature has been driven primarily — if not almost entirely — by human activity (see Scientist: “Our conclusions were misinterpreted” by Inhofe, CO2 — but not the sun — “is significantly correlated” with temperature since 1850 and Part 3 [to come]).
4. Absent human emissions, we’d probably be in a slow long-term cooling trend due primarily by changes in the Earth’s orbit — see Human-caused Arctic warming overtakes 2,000 years of natural cooling, “seminal” study finds.
5. Thus, the rate of human-driven warming in the last century has exceeded the rate of the underlying natural trend by more than a factor of 10, possibly much more.  And warming this century  on our current path of unrestricted greenhouse gas emissions is projected to cause a rate of warming that is another factor of 5 or more greater than that of the last century.  We are punching the climate beast — and she ain’t happy about it!

Back to the investigation of attempted murder — and the ‘innocent victim’ who may have been killed in the attempt.  The folks who don’t follow climate science closely have been trumpeting a new paper “A Statistical Analysis of Multiple Temperature Proxies: Are Reconstructions of Surface Temperatures Over the Last 1000 Years Reliable?” by McShane and Wyner about to be published in Annals of Applied Statistics.   Supposedly it is fatal to the Hockey Stick.

Here is the police lineup.  Take a look at three independent reconstructions of the past one to two  millennia and the new one by the statisticians — and see if you can pick out which one allegedly killed the others (with apologies to Deltoid):

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Physicist John Cook of Skeptical Science has two good pieces on global dimming and global brightening I’m combining and reposting here.

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Here is an update of my review of the best papers on climate science in the past year.  If you want a broader overview of the literature in the past few years, focusing specifically on how unrestricted emissions of greenhouse gas emissions are projected to impact the United States, try “An introduction to global warming impacts: Hell and High Water.”

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Warning:  Please put your head in a vise before reading further.

Andy Revkin has just written the most illogical climate post on Earth.  Or maybe he’s written the most logical climate post on the Bizarro World Htrae.

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According to the IPCC 4th Assessment Report (2007):
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A strong, credible body of scientific evidence shows that climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems….

Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small. Such conclusions and theories are then regarded as settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities.

The National Academy released three reports today on “America’s Climate Choices.”

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Revkin asks me via Dot Earth, “What if The Public had Perfect Climate Information?”  Ahh, the hypothetical question that launches us into an alternative history.  Reminds me of that Saturday Night Live routine, “What if Spartacus had a Piper Cub?”

I’d love your answer.  Here’s mine.

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UPDATE:  Judith Curry comments below — including this new puzzler.  I reply.  Feel free to do the same.

As a general rule for scientists, one shouldn’t hitch one’s wagon to long-debunked purveyors of disinformation.  Because then you might end up circling the wagons with the wrong … tribe (see “The curious incident of Judith Curry with the fringe“).

I’m on a plane today, so I commend to you an outstanding Real Climate post, “The Montford Delusion,” by Tamino — and the stunning comments section.  NASA scientist Gavin Schmidt and Tamino are in the role of Wyatt Earp, Doc Holliday and company.  Judith Curry (and Peter Webster) have apparently thrown in with the Clantons.  Like all analogies, this one isn’t perfect, but I’m afraid the outcome is pretty much the same.

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James Powell, Executive Director, National Physical Science Consortium, has produced an excellent YouTube video summarizing the evidence for anthropogenic global warming

Powell is a former college and museum president.  “President Reagan and later, President George H. W. Bush, both appointed Powell to the National Science Board, where he served for 12 years.”

Great for sending to any septics you may know:

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Physicist John Cook of Skeptical Science has a good post debunking the global cooling myth, “3 levels of cherry picking in a single argument,” reprinted below.

To properly understand what’s happening to our climate, you have to consider the full body of evidence. Most arguments that support climate skepticism have one thing in common — they neglect the full body of evidence and cherry pick just the select pieces of data that support a particular point of view. There is one argument that is so misleading — it requires 3 separate levels of cherry picking. This argument is “global warming stopped in 1998“. Let’s look at the 3 ways it cherry picks the data:

Cherry Pick #1: Select one particular temperature record

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Please offer suggestions for improving the one liners below.

Progressives should know the most commonly used arguments by the disinformers and doubters — and how to answer them.  You should know as much of the science behind those rebuttals as possible, and a great place to start is SkepticalScience.com.

BUT most of the time your best response is to give the pithiest response possible, and then refer people to a  specific website  that has a more detailed scientific explanation with links to the original science.   That’s because usually those you are talking to are rarely in a position to adjudicate scientific arguments.  Indeed, they would probably tune out.  Also,  unless you know the science cold,  you are as likely as not to make a  misstatement.

Physicist John Cook has done us a great service by posting good one-line responses, which I repost with links below.  For instance,  if somebody  raises the standard talking point that the climate has changed before, you can say, “Climate reacts to whatever forces it to change at the time, which now is dominated by humans.”  That  it is actually quite similar to my standard response, “The climate changes  when it is forced to change,  and now humans are forcing it to change far more rapidly than in the past” (see “Humans boosting CO2 14,000 times faster than nature, overwhelming slow negative feedbacks” and “Yes, the atmospheric CO2 fraction has risen at a dangerously fast rate in the past 160 years, reaching levels not seen in millions of years“).  Working in the “now is dominated by humans” part is a good idea.

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