IPCC + Bodman

03 February 2007

The IPCC released the Summary for Policymakers section of their fourth assessment report (AR4) yesterday. Some highlights:

  • "The understanding of anthropogenic warming and cooling influences on climate has improved since the Third Assessment Report (TAR), leading to very high confidence [>90% certainty] that the globally averaged net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 W/m^2."
  • "Changes in solar irradiance since 1750 are estimated to cause a radiative forcing of +0.12 W/m^2, which is less than half the estimate given in the TAR."
  • "The combined radiative forcing due to increases in carbon dioxide, methane, and nitrous oxide is +2.30 W/m^2, and its rate of increase during the industrial era is very likely [>90% certainty] to have been unprecedented in more than 10,000 years. The carbon dioxide radiative forcing increased by 20% from 1995 to 2005, the largest change for any decade in at least the last 200 years."
  • "Average Northern Hemisphere temperatures during the last half of the 20th century were very likely [>90% certainty] higher than during any other 50-year period in the last 500 years and likely [>66% certainty] the highest in at least the past 1300 years."
Secretary of Energy Samuel Bodman had this to say:
“Even if we were successful in accomplishing some kind of debate and discussion about what caps might be here in the United States, we are a small contributor to the overall, when you look at the rest of the world, so it’s really got to be a global solution.”
However, the US actually contributes about 1/4 of the world's greenhouse gas emissions.

It is also disingenuous to suggest that we might be the only ones to act. Here is a map of the 161 countries which have ratified the Kyoto Treaty, which uses a cap-and trade system to reduce greenhouse gas emissions:

We're hardly alone in this. That being said, I do agree that mandatory caps could possibly be ineffective. If the United States were to cap carbon dioxide emissions, it is likely that the industries affected would simply move their operations into countries with more lax emissions standards. China and India, as well as other "developing counties", are exempt from emissions cuts under Kyoto, even though China will likely become the top contributor in the future.

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