Next there is the problem of attributing temperature changes to CO2 emissions. In the recent report of the Intergovernmental Panel on Climate Change (IPCC), Figure 9.1
shows that the main effect of CO2 over the past century (see panel (c)) should have been a strong warming in the mid-troposphere over the tropics. Figure 10.7
shows the same pattern resulting from current and future CO2 emissions. Changes are also projected at the surface in the polar regions. However they are not so easy to tie to greenhouse gases since those regions are also sensitive to solar variability and natural atmospheric oscillations.
The tropical troposphere stands out as a good place to measure the specific effects of CO2. The contour lines imply an expected warming of the tropical tropospheric of 1-2 degrees Celsius over four decades starting in 1980, implying a warming of one-quarter to one-half degree Celsius per decade should now be observable.
Satellite data for the tropical mid-troposphere is available from the University of Alabama and from Remote Sensing Systems
in California. These series track each other closely. There were some processing differences in the early decades but in recent years the two have converged.
Taking the average of the two series, there is a 30-year trend over the tropics of six-hundredths of a degree Celsius per decade, and it is statistically insignificant (when applying the appropriate autocorrelation correction). In other words, the data do not show the warming trend that the models say should be under way, if greenhouse gases have such a big effect on the climate.
Last summer I testified before Congress regarding proposed greenhouse gas regulation. U.S. Rep. John Dingell (D-Dearborn) wrote me a follow-up letter asking about, among other things, the tropical troposphere. My response letter is online
, along with the computer code to retrieve the data and compute the trends.
There are other clues that the effect of greenhouse gases may have been overstated. The stratosphere is supposed to be cooling, but the satellite instruments show that since 1995 there has been no such trend.
The upper 700 meters of the oceans should be accumulating heat. But since 2003 we have had a global network of 3,000 robotic buoys monitoring the oceans (see www.argo.net
) and they have shown no such heat accumulation.
I know that the IPCC supposedly has thousands of experts who all say that global warming is a crisis. I was one of the people who worked on that report. The reality is they never asked us if we agreed with the conclusions, and only a handful of authors had a say in the final summary. In any case, I don’t care how many professors agree or disagree on something, what matters is whether I agree with the data.
Our best current data sets do not support the idea that CO2 is causing a global warming problem. New laws to reduce CO2 levels will lead to higher energy prices and more unemployment, and would not affect global CO2 levels anyway. Americans seem to be realizing that costly CO2 regulations are a bad idea. I agree.
Ross McKitrick is a professor of economics at the University of Guelph, in Ontario, where he focuses on environmental economics. His first entry and previous guest bloggers, including the three university professors who blogged about climate change June 2-4, are compiled here.
Climate change? No worries here
Polls show that global warming has fallen to the bottom of the list of Americans’ worries. Meanwhile 170 Michigan professors signed a letter
calling for tough climate legislation. I read the professors’ letter, and I have to say I’m with the people on this one.
Their letter would be more convincing if they weren’t so dismissive of the costs involved. They cite unnamed “recent studies” that claim emission cuts could create 150,000 jobs in Michigan. I put more stock in the analysis
by the Energy Information Administration of last year’s Lieberman-Warner bill (which is similar to the Waxman-Markey bill now before Congress).
The EIA pointed out that cutting carbon dioxide (CO2) emissions requires driving up energy prices, and this will shrink the economy. U.S. manufacturing would decline by 3% to 7%, depending on how lucky the United States is at developing alternative energy sources, and manufacturing employment will fall between 3% and 10% (p. 39). Of course the professors won’t lose their jobs, but they should still be concerned about these things.
It is true that if you could convince taxpayers in the other 49 states to subsidize new, money-losing green energy projects in Michigan, then you might gain some jobs. But when every other state is hoping to pull the same trick on you, it’s a zero-sum game. Actually it’s worse: Subsidies for green jobs end up reducing national employment, not increasing it.
I also found the letter’s scientific content unconvincing. Regional climate forecasting is very conjectural, and models often contradict each other. I suppose it is possible that all four trout species could disappear as a result of a few degrees of warming over 100 years, but if trout were that delicate, the annual arrival of summer would have wiped them out long ago.
As for the litany of potential damages from recent warming trends, I browsed some of the longest weather station histories for Michigan, such as Grand Rapids, Cheboygan and others. There are some trends, but after 1920 they are pretty small, especially considering the known warming bias in long-term climate data from regions undergoing urbanization.
The professors claim that these small trends could, among other things, destroy Michigan agriculture. Let’s give farmers a bit more credit. If farmers could not adapt to weather variability, agriculture in Michigan would have disappeared by the 1930s.
Even if the long list of problems could be blamed on CO2 emissions, the professors failed to mention that the small cuts envisioned under the proposed regulations would not change anything. The differences would be minuscule at the global scale, which is where they matter.
Next: Looking at the data on carbon dioxide and temperatures.
Ross McKitrick is a professor of economics at the University of Guelph, in Ontario, where he focuses on environmental economics. Previous guest bloggers, including the three university professors who blogged about climate change June 2-4, are compiled here.