What were Gore’s great gaffes worthy of scorn from the esteemed think tank?
First he suggested dramatic increases in sea level if significant ice sheets were to melt.
You know, even a one-meter increase, even a three-foot increase in sea level would cause tens of millions of climate refugees.
If Greenland were to break up and slip into the sea or West Antarctica, or half of either and half of both, it would be a 20-feet increase, and that would lead to more than 450 million climate refugees.
Then he suggested a link between global warming and droughts:
Today, 49 percent of America is in conditions of drought or near drought. And we have had droughts in the past, but the odds of serious droughts increase when the average temperatures go up, as they have been going up.
We have fires in California, in Florida, in other states, unprecedented fire season last year, directly correlated with higher temperatures, which dry out the soils, dry out the vegetation.
Then he dared to suggest global warming might adversely affect agriculture:
We have a very serious threat of losing enough soil moisture in a hotter world that agriculture here in the United States would be greatly affected.
What was Pat Michaels response? Well the usual misinterpretations and cherry-picking.
FACT 1. There is not one shred of evidence in the refereed scientific literature speaking of a three-foot increase in sea level in ten years. The best estimates from the United Nations Intergovernmental Panel on Climate Change range from 0.8 to 1.7 INCHES.
Interesting, I didn’t see that Al Gore suggested that sea levels would rise 3 feet in ten years, and the IPCC report specifically mentions that their considerations of sea level rise do not include considerations of increases that would be brought about from the loss of major ice sheets. So, I’d say this is a straw man and cherry-pick. The real source of that kind of projection is discussed at RealClimate and is based on studies of ancient climate in which those regions were deglaciated resulting in 3-4 meter increased sea levels. The concern is that these sea level rises will occur in about 100 years when temperatures reach those seen during these previous periods of deglaciation. This is not an unreasonable assumption.
FACT 2. There is no trend towards increasing drought area in the United States that is related to planetary warming. We have good data on drought area back to 1895. The correlation between the area of the U.S. under drought and planetary temperature is statistically ZERO.
Well, here is where we do have a sloppy statement from Gore. It would be inaccurate to say that drought is occurring right now at these levels as we’re just getting into summer when droughts become more common. A more accurate statement would be we’ve seen increasing droughts in the last decade, reaching as high as 49-51 percent in 1999-2002, 2004 and 2005. Right now about 29% of the US is experiencing some level of drought as of March which isn’t too bad (full data here) and we haven’t seen extended droughts as bad as those during the dust bowl. The other issue is that drought caused by warming won’t necessarily be reflected in increases in these total areas of drought to which Gore refers. There is a difference between alleging an increase in frequency of droughts as a result of warming and an increase in area suffering from drought. Global warming will likely result in more severe droughts in the southwest and higher precipitation in the northeast and Canada according to the IPCC models. Michaels is therefore still wrong when he suggests there isn’t any data to suggest increasing drought in the US as a risk of global warming, but then, he probably only sees what he wants to in the AR4 IPCC report (specifically regional climate predictions (PDF)).
As far as the link between warming and droughts, it is a reasonable statement based on findings like these from the 2001 TAR which suggest a link between warming and extreme weather.
Superimposed on the changing development landscape is the possibility that climate warming will reduce the risk of some extreme events and increase the risk of others (Karl et al., 1996; White and Etkin, 1997). Changes in the frequency, severity, and duration of extreme events may be among the most important risks associated with climate change. In some parts of North America, this includes fewer periods of extreme cold, fewer snowstorms (although there may be an increase in the number of intense storms), increased spring flooding, more frequent summer droughts, and more wildfires. Studies also suggest that there will be a more thermodynamically unstable atmosphere in the future, which probably will result in more frequent heavy rainfalls and possibly increased hail risk and more tornadoes and downbursts (Etkin, 1996).
What’s Michaels’ last great assertion about Gore’s lies?
FACT 3. As the mean planetary temperature has warmed since 1975, U.S. crop yields have INCREASED significantly, just as they did during the period of cooling from 1945 through 1975, or during the warming from 1910 to 1945.
It is a true outrage that Gore can get away with this on live television and not be called out by the inconvenient facts.
Now this is just a red herring and straw man. Crop yields increase, sure, this is for many reasons including better methods, more efficient technology and genetic engineering. But that has nothing to do with whether agriculture will be adversely affected by global warming. Sure yields have been increasing, and might continue to increase, but variability from climate change as suggested by the 2001 TAR may result in decreased efficiency which means increased cost of production. No one is saying that past warming has affected crops or was even bad for crops, this is just besides the point. The issue is what future warming might do in terms of economic harm from more frequent extreme weather events and overall increased temperatures.
PS. I’m not an expert in global warming either, but I read the assessment reports, and more importantly recognize BS arguments from denialists when I see them. If anyone with greater expertise on global warming would like to correct my understanding of the science I will welcome the criticism. But I don’t expect any errors I have made will make Michaels’ cherry-picking and logical fallacies any less blatant.