Speaking at the Heartland Institute’s climate denial conference in Chicago this afternoon, Congressman Jim Sensenbrenner (R-WI) said that labeling heat-trapping carbon dioxide a pollutant is “propaganda.”

Sensenbrenner is a long-time climate disinformer who says that the science of man-made global warming is an “international conspiracy.” He also happens to be Vice Chair of the House Committee on Space, Science and Technology.

Blatantly ignoring the “science” part of his committee responsibilities, the Congressman today attempted to argue against the basic physics of CO2 in the atmosphere:

“CO2 is a natural gas. Does this mean that all of us need to put catalytic converters on all our noses? The fact that people think CO2 is a pollutant … basically goes into propaganda.”

The so-called “radiative forcing” of carbon dioxide from burning fossil fuels has contributed enough heat in the atmosphere over the last century to equal roughly half a billion Hiroshima nuclear bombs each year. As one researcher explained: “When there’s more energy radiating down on the planet than there is radiating back out to space, something’s going to have to heat up.”

Rep. Sensenbrenner took his unscientific personal conclusions one step further, saying he believed CO2 would help “crop yields go up” and make it “easier to feed 7 billion people.”

“I’m not one of the people going around saying CO2 is bad for you,” he concluded.

In fact, scientists around the world are calling man-made global warming one of the biggest threats to agricultural production. In Texas, a brutal warming-driven drought cost farmers $7.5 billion last year; In Thailand, “weather whiplash” in 2010 devastated rice crops, causing $40 billion in lost economic productivity; and in Mexico, severe drought reduced agricultural output by 40% already this year.

These incidents came as world food prices hit record highs in 2011 due to a combination of extreme weather events and rising oil prices. In the lead-up to these global price spikes, 2010 was the warmest year on record globally — with 19 nations setting all-time heat records.

Sensenbrenner delivered his speech to a crowd of roughly 200 people at the Heartland Institute’s 7th annual international climate conference — a yearly gathering for the nation’s most active climate change disinformers. The Heartland Institute has come under fire in recent weeks for a disastrous billboard campaign linking people who understand human-caused global warming to mass murderers. Since the billboard was put up, 12 companies have pulled their support for Heartland in the lead-up to the conference.

Sensenbrenner ended his speech with an appropriate anecodote. He referenced New York Times Columnist Paul Krugman, who wrote in a 2009 column that climate deniers were practicing “treason against the planet.”

“Mr. Krugman, I plead guilty as charged,” boasted Sensenbrenner — a politician who helps oversee one of the most important scientific committees in Congress.

The crowd burst into gleeful laughter.

Sensenbrenner also assured the crowd that Mitt Romney would not take action on global warming. When asked by an attendee who said he was “scared to death” that Romney would change his stance on man-made global warming and support renewable energy, Sensenbrenner replied, ” I don’t think that’s true. I talked to Romney before the Wisconsin primary.”

JR: Climate science has long predicted an expansion of the tropical belt (colored band in figure below), which we’re now observing. At the same time, also as predicted, the subtropical dry zones are shifting poleward and getting drier (see for instance, this study and this one). And that means more “Dust-Bowlification,” which is a grave threat to food security. This observed expansion is happening faster than the climate models projected. A new study in Nature (subs. req’d) offers one possible explanation for this. What follows is a news release on the study.

by Iqbal Pittalwala, via UCR Today

Black carbon aerosols and tropospheric ozone, both manmade pollutants emitted predominantly in the Northern Hemisphere’s low- to mid-latitudes, are most likely pushing the boundary of the tropics further poleward in that hemisphere, new research by a team of scientists shows.

While stratospheric ozone depletion has already been shown to be the primary driver of the expansion of the tropics in the Southern Hemisphere, the researchers are the first to report that black carbon and tropospheric ozone are the most likely primary drivers of the tropical expansion observed in the Northern Hemisphere.

Led by climatologist Robert J. Allen, an assistant professor of Earth sciences at the University of California, Riverside, the research team notes that an unabated tropical belt expansion would impact large-scale atmospheric circulation, especially in the subtropics and mid-latitudes.

“If the tropics are moving poleward, then the subtropics will become even drier,” Allen said.  “If a poleward displacement of the mid-latitude storm tracks also occurs, this will shift mid-latitude precipitation poleward, impacting regional agriculture, economy, and society.”

Study results appear in the May 17 issue of Nature.

Observations show that the tropics have widened by 0.7 degrees latitude per decade, with warming from greenhouse gases also contributing to the expansion in both hemispheres. To study this expansion, the researchers first compared observational data with simulated data from climate models for 1979-1999.  The simulated data were generated by a collection of 20 climate models called the Coupled Model Intercomparison Project version 3 or “CMIP3.”

The researchers found that CMIP3 underestimates the observed 0.35 degrees latitude per decade expansion of the Northern Hemisphere tropics by about a third.  But when they included either black carbon or tropospheric ozone or both in CMIP3, the simulations mimicked observations better, suggesting that the pollutants were playing a role in the Northern Hemisphere tropical expansion.

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