I asserted in Part 1 that economists don’t understand climate science. Exhibit 1 would be Robert Mendelsohn, an economics professor at Yale University, whose “research” has prompted headlines in our neighbor up north like “A warmer climate could hold lots of benefits for Canada” and “The UP side of global warming“:

Leading the charge is Robert Mendelsohn, an economics professor at Yale University, who says the benefits of global warming for Canada — from a longer growing season to the opening up of shipping through the Northwest Passage — will outweigh the negative effects.

“You’re lucky because you’re a northern-latitude country, Mendelsohn says. “If you add it all up, it’s a good thing for Canada.”

This series will have three recurring themes about Voodoo Economists aka Mainstream Economists who Opine on Weather (MEOWs):

1. MEOW’s understanding of what global warming is doing to the planet now and what it is likely to do by 2100 on our current emissions path ranges from arrogantly incomplete to criminally ignorant. They really talk more about the weather than the climate.
2. MEOW’s cost-benefit calculations ["if you add it all up"] are analytically unsound and qualify more as an opinion than a scientifically accurate statement.
3. The right wing loves what the economics profession is saying and publishing on climate, which is why they quote and cite them so giddily.

For instance, you would never know from this article — or any of Mendelsohn’s comments — that Canada is already suffering widespread and completely unpredicted devastation from climate change, as I’ve written (see “Climate-Driven Pest Devours N. American Forests” and “Nature on stunning new climate feedback: Beetle tree kill releases more carbon than fires“):

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“Ignoring climate projections at this stage will only result in the worst form of triage.”

The headline is from the University of Washington news release on a study in Science, “Historical Warnings of Future Food Insecurity with Unprecedented Seasonal Heat.” The quote is the study’s powerful final sentence. The release explains:

Rapidly warming climate is likely to seriously alter crop yields in the tropics and subtropics by the end of this century and, without adaptation, will leave half the world’s population facing serious food shortages, new research shows….

“The stresses on global food production from temperature alone are going to be huge, and that doesn’t take into account water supplies stressed by the higher temperatures,” said David Battisti, a University of Washington atmospheric sciences professor.

Worse, the study must also be considered a serious underestimate of likely impacts since, as is common in such analyses, they based their simulations on “the ‘middle of the road’ emission scenario, A1B.” In 2100, A1B hits about 700 ppm with average global temperatures “only” about 3°C warmer than today. In fact, on our current emissions path, we are going to get much, much hotter (see Hadley Center: “Catastrophic” 5-7°C warming by 2100 on current emissions path).

Figure. “Histogram of summer (June, July, and August) averaged temperatures (blue) observed from 1900 to 2006 and (red) projected for 2090 for (A) France, (B) Ukraine, and (C) the Sahel. Temperature is plotted as the departure from the long-term (1900–2006) climatological mean (21). The data are normalized to represent 100 seasons in each histogram. In (A), for example, the hottest summer on record in France (2003) is 3.6°C above the long-term climatology. The average summer temperature in 2090 [assuming A1B] is projected to be 3.7°C greater than the long-term climatological average.”

The results are still alarming:

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