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Hot Enough For You?

Dan Lashof

Posted July 7, 2010

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The oppressive heat wave gripping the Eastern United States, by itself, shouldn’t have any influence on what policymakers think about global warming. But after the ridiculous spectacle of climate science deniers claiming that last winter’s blizzard disproves global warming, I hope that the record heat we are experiencing now will help focus their minds on the underlying science. A string of recent authoritative reports unequivocally reaffirming the science and rejecting the malicious allegations against climate scientists provides plenty of material to focus on.

Last winter was the perfect storm for climate science deniers. They scoured thousands of stolen emails to cherry pick a handful that appeared to cast doubt on the integrity of climate scientists, a few mistakes were found in the IPCC report on climate change impacts, and a cold and snowy winter blanketed the East Coast. As I said at the time, none of this changed the facts on the ground, in the air, or in the ocean. That’s true of an isolated heat wave also, but this heat wave is part of a clear trend of increasingly severe and frequent heat. In fact, the last twelve months was the hottest twelve month period on record, and the last decade was the hottest decade on record. As Tom Peterson, Chief Scientist for NOAA’s National Climatic Data Center said recently:

We’re getting a dramatic taste of the kind of weather we are on course to bequeath to our grandchildren.

High temperatures for June and July.gif

GISS 12 month running mean.png

The record heat of the last few weeks has been matched by a record string of reports reaffirming the underlying science.

Let’s start with the most comprehensive and authoritative. The National Academy of Science released the three primary components of its America’s Climate Choices report in May, addressing the fundamental science, limiting the magnitude, and adapting to the impacts of climate change.

The Acadamy’s conclusions are as definitive as science gets:

Climate change is occurring, is caused largely by human activities, and poses significant risks for—and in many cases is already affecting—a broad range of human and natural systems.

Most of the warming over the last several decades can be attributed to human activities that release carbon dioxide (CO2) and other heat-trapping greenhouse gases (GHGs) into the atmosphere. The burning of fossil fuels—coal, oil, and natural gas—for energy is the single largest human driver of climate change, but agriculture, forest clearing, and certain industrial activities also make significant contributions.

Individually and collectively, these changes pose risks for a wide range of human and environmental systems, including freshwater resources, the coastal environment, ecosystems, agriculture, fisheries, human health, and national security, among others.

Shamefully, this authoritative report has received far less media coverage than the unsubstantiated, and now disproven, allegations against individual climate scientists. Sure, hacked emails and innuendo about wrongdoing are sexier than the solid clear conclusions of an institution such as the National Academy of Sciences. But are they more newsworthy? Journalists have a responsibility to evaluate the meaning and significance of allegations before spreading them. In the case of the so-called “climate gate” episode they mostly failed at that responsibility.

Now journalists have an opportunity to set the record straight, as Media Matters, NRDC, and others urged them to do yesterday. The Project on Climate Science summarized the conclusion of the latest report, which also came out yesterday, to find baseless the allegations arising from the hacked emails:

The Independent Climate Change E-mails Review, also known as the Muir Russell report, declared today that it “did not find any evidence of behaviour that might undermine the conclusions of the IPCC assessments.” Regarding the actions of the scientists of the Climate Research Unit of the University of East Anglia, the report stated that “their rigour and honesty as scientists are not in doubt.”

This report is the last in a series of three investigations in the United Kingdom into the alleged wrong-doing by climate scientists. It also comes on the heels of the exoneration of Professor Michael Mann from investigations at Penn State University.

Here are three additional examples as summarized in the Media Matters letter:

Responding to allegations that Dr. Michael Mann tampered with scientific evidence, Pennsylvania State University conducted a thorough investigation. It concluded, "The Investigatory Committee, after careful review of all available evidence, determined that there is no substance to the allegation against Dr. Michael E. Mann, Professor, Department of Meteorology, The Pennsylvania State University.  More specifically, the Investigatory Committee determined that Dr. Michael E. Mann did not engage in, nor did he participate in, directly or indirectly, any actions t hat seriously deviated from accepted practices within the academic community for proposing, conducting, or reporting research, or other scholarly activities."

London's Sunday Times retracted its story, echoed by dozens of outlets, that the IPCC issued an unsubstantiated report claiming 40 percent of the Amazon rainforest was endangered due to changing rainfall patterns. The Times wrote, "In fact, the IPCC's Amazon statement is supported by peer-reviewed scientific evidence. In the case of the WWF [World Wildlife Fund] report, the figure had, in error, not been referenced, but was based on research by the respected Amazon Environmental Research Institute (IPAM) which did relate to the impact of climate change."

After analyzing 32 summary conclusions on the regional impacts of climate change in the IPCC's 2007 Fourth Assessment Report, the Netherlands Environmental Assessment Agency concluded that "no significant errors" had been made.

This swarm of data and reports should close this chapter in the long-running saga written by the Merchants of Doubt. Ideologically-driven climate science deniers will doubtless come up with new arguments, but next time let’s hope that the media won’t go along for the ride.

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William NydenJul 7 2010 09:28 PM

According to Piers Corbyn, it's all caused by a stronger solar wind emitted from coronal holes:
He predicts weather based on solar activity, loudly declaiming the successes of his patent techniques and ignoring the failures. Greenhouse gases have nothing to do with it.

Dennis JohnsonJul 8 2010 02:03 AM

For most countries the science is clear ten years ago. The USA being the largest per person energy consumer and greenhouse gas contributors should quit blowing hot air and do something. Institute a Sustainable Energy Policy that isn’t just lip service.

Mark RicciarelliJul 8 2010 08:44 AM

Where are the sources for this article? Where does it show conclusively that CO2 generated by human activity contributes to global warming? This isn't science, this is propaganda at it's finest. The trouble with folks this days is that people think they are correct about a whole lot of stuff they don't know.

Dan LashofJul 8 2010 08:50 AM

Mark-Please follow the links in this post, which take you directly to the original sources, including the National Academy of Sciences report as well as the NASA data.

Jennifer JordanJul 8 2010 11:37 PM

As a former research assistant to Dan at NRDC 20 years ago, I can attest to his scientific rigor and integrity. He has nothing to gain personally and takes the stance he does based on his love of this planet and his commitment to the facts.

I personally found it difficult to remain in the profession as the facts can be difficult to swallow and the resistance from others even harder still.

So thank you for staying, Dan. For being a clear, sane, and steady voice. And for being brave enough to make a stand on an uncomfortable truth. Your commitment is highly admirable.

Jennifer Jordan

Dan LashofJul 9 2010 06:55 AM

Thanks Jennifer. It's nice to hear from you.

Jennifer JordanJul 9 2010 09:55 AM

You are welcome Dan. I follow NRDC's FB posts and, having worked there, I know I am getting information of the highest caliber.

I work in the health field professionally and have for 13 years. In our community of Cabin John a few of us -- with the great support of the community -- have formed a loose group called Green Neighbors and we work on taking action on environmental issues right here where we live. It has been very powerful to work with the 100s of folks we know and live around, to see how we can take responsibility and make changes right here, right at home.

(we are working on a new website)

In the meantime, I remain proud to have been a small part of NRDC, a non-profit organization of the highest caliber.

Mark RicciarelliJul 9 2010 01:22 PM

Again...Where does it show conclusively that CO2 generated by human activity contributes to global warming (besides the conclusion of suspect people I don't know and have never met)? Forgive me Dan but can you point me in the right direction? I see a lot of graphs and data associated with temperatures rising. where is the data that shows first that the concentration of CO2 increased atmospherically (where in the atmosphere?) and that temperature rose based on increased CO2 concentration and not from Ocean temperature rising and releasing CO2. I am not challenging your integrity or good intentions nor the fact that polluting the earth is bad. If you are asking me to take someones word for it then forget it. I want proof and have yet to see it. I see absolutely nothing in the links that would lead me to believe anything other than it's getting hotter. Can you help me out and show me where the data is?

Dan LashofJul 10 2010 09:57 AM

There is a vast literature on which the National Academy of Sciences based its conclusion that "Most of the warming over the last several decades can be attributed to human activities that release carbon dioxide (CO2) and other heat-trapping greenhouse gases (GHGs) into the atmosphere." I'm not asking you to take this on faith, but I don't know why you think the U.S. National Academy of Sciences is suspect, and given that attitude I don't know if there are any data that can convince you, but I will give it a try.

The basic data showing CO2 increasing in the atmosphere (and it is increasing everywhere--there a slight variations but CO2 is long-lived in tthe atmoshphere and therefore well mixed) are here:

Chapter 9 of the IPCC report is a good introduction to the literature on attributing observed global warming to increases in the concentration of CO2 and other greenhouse gases in the atmosphere. Perhaps the singlest clearest graph is here:

Another particularly compelling data set is the increase in the heat content of the ocean, which can only be explained by a fundamental imbalance between the amount of energy the earth receives from the sun and the amount of energy reradiated to space due to the build up of heat-trapping gases. See:

For additional data and other resources on the web, I highly recommend and SkepticalScience also has an excellent iPhone app if you want to carry the data around with you.

ThomasJul 10 2010 09:12 PM

It's easy to calculate how much heating a given increase in CO2 would produce if everything else remains the same. That amount is trivial and could not harm us or the plant. Life has always altered the climate and always will. If ancient bacteria had not polluted the atmosphere with oxygen, we would not be here.

"London's Sunday Times retracted its story, echoed by dozens of outlets, that the IPCC issued an unsubstantiated report"

Today the published an article on "Amazongate" showing that the IPCC statement about possible effects in the amazon was lifted from a non-peer reviewed "anonymous note" on the WWF websites. The IPCC exaggerated the statements in the note, which was not even about climate change effects, and presented it as if it were peer reviewed science.

The WWF stands to profit from a scheme to sell carbon credits "generated" by its "management" of amazon rain forests.

Dr. Mann recently admitted to BBC that his famous hockey stick graph, which in fact did use a trick to hide a decline, was so uncertain that it should never have been adopted as an icon of the global warming political movement.

I could go on

adamcourtJul 10 2010 10:17 PM

Look, you're going to get nowhere without disproving the so-called disprovers. There's nothing you've told me from the above that will put the slightest dent in the climate deniers' pitch. Cannot the IPPC go out and prove, with a no-holes barred peer-reviewed study, that 40 per cent of the Amazon IS in danger. Do that, and the rest of us climate agnostics, who are being pulled one way or the other, will be right behind you. The rest, as they say, is just talk. And there's been oh so much of that.

thomasJul 12 2010 02:55 AM


Thanks for publishing my comments. I've tied to make similar comments on, for example, but the presumably prejudiced moderators never post them. I appreciate that you are not like them.

You wrote, "Another particularly compelling data set is the increase in the heat content of the ocean, which can only be explained by a fundamental imbalance between the amount of energy the earth receives from the sun and the amount of energy reradiated to space due to the build up of heat-trapping gases."

"Which can ONLY be explained by" is the part I object too. Perhaps increased ocean heat is a valid observation but to conclude that it can only be explained by greenhouse warming is a bit disingenuous. The fact that you may think there is only the one explanation for is not sufficient proof that ocean warming is caused by greenhouse warming. There could be many other explanation that you and others have not yet considered.

How much ocean warming has been measured and how was it measured? I don't think anyone measured ocean temperature a hundred years ago so we may have nothing to compare today's measurements to.

Also, why can't any ocean warming be due to natural variability in other factors such as, for example, clouds? Isn't it well accepted that we don't know enough about the dynamics of global cloud formation to even make rough estimates of how to deal with them in climate models?

Chaos theory, a fascinating but misnamed subject, grew out of the idea that forecasting weather might be impossible due to fact that future weather is highly dependent on initial conditions which are unknowable in their fine detail. (The butterfly's wing idea.) It seams current climate science mostly ignores this probable fact.

As for the "precautionary principal," every time I get up and drive to work I am take a significant personal risk. But of course I do it anyway.


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