May 21, 2009

Shoveling Sand

As we have discussed here, and as has been discussed elsewhere, it is straightforward to determine the likely climate impact from legislation aimed at reducing greenhouse gas emissions.

Yesterday we showed how little climate impact the proposed national fuel efficiency standards would have, today we turn our attention to the climate impact of the proposed Waxman-Markey American Clean Energy and Security Act—which despite the name, is squarely aimed at attempting to mitigate future global climate change.

What we are interested in is this: if the U.S. is successful in meeting the greenhouse gas emissions reductions as prescribed in the Waxman-Markey legislation (ultimately a 83% reduction in U.S. greenhouse gas emissions by the year 2050), how much global warming would be averted?

The best way to answer this question would be to use a general circulation model but they are costly to run (both in dollars and in time). Instead, we’ll use the Model for the Assessment of Greenhouse-gas Induced Climate Change, or MAGICC, which was developed at NCAR primarily by Dr Tom Wigley for this express purpose—that is, emulating the results of full climate models without the cost or time constraint. MAGICC runs on your desktop in seconds and for free.

To assess the climate impact of the Waxman-Markey restrictions, we first have to develop a baseline from which to apply the emissions reductions. In this case, we use the middle-of-the-road emissions scenario (A1B) as developed by the Intergovernmental Panel on Climate Change (IPCC). We then run MAGICC (using its default parameter settings) with the before and after emissions scenarios to produce the projections of future global temperature.

When we do this, here is what we get:


Year 2050
Warming from 1990 to 2050, A1B; 1.58ºC
Warming from 1990 to 2050, Waxman-Markey U.S.; 1.54ºC
“Savings” from Waxman-Markey U.S.; 0.04ºC
Percent Warming “Saved”; 2.5%

Year 2100
Warming from 1990 to 2100, A1B; 2.96ºC
Warming from
1990 to 2100, Waxman-Markey U.S.; 2.85ºC
Temperature “Savings” from
Waxman-Markey U.S.; 0.11ºC
Percent Warming “Saved”; 3.7%

For the optimists in the crowd who think that the U.S. will not be acting alone, we also ran the case assuming that all the countries that agreed to Kyoto Protocol emissions targets would follow a similar emissions reduction course as the U.S.


Year 2050
Warming from 1990 to
2050, A1B; 1.58ºC
Warming from 1990 to 2050, Waxman-Markey Kyoto; 1.50ºC
Temperature “Savings” from Waxman-Markey Kyoto; 0.08ºC
Percent Warming
“Saved”; 5.0%

Year 2100
Warming from 1990 to 2100, A1B; 2.96ºC
Warming from 1990 to 2100, Waxman-Markey Kyoto; 2.74ºC
“Savings” from Waxman-Markey Kyoto; 0.22ºC
Percent Warming “Saved”; 7.4%

The bottom line here is that we are talking about global temperature savings on the order of one or two tenths of a degree by the end of the century even if the rest of the developed world does the same—values that are virtually meaningless when held against the total projected temperature rise.

Consequently, no matter how you slice it, the Waxman-Markey proposal is a completely futile legislative exercise, in terms of effect on global warming.


1 comment:

  1. Bjorn Lomburg did a similar analysis a few years ago. If all countries completely eliminated CO2 emissions, then there would be an itsy bitsy change in temps.
    As Jo Nova explains there is only one argument. Does CO2 cause global warming. If it does then there is a debate. If it does not, then there is no debate - Global Warming is caused by other factors which are not identified by the IPCC (hmm - The Sun).
    An increase in CO2 has never in history been followed by temp increases. Never. CO2 increases follow temp changes - about 800 years later.

    So there is no argument. The science IS settled. CO2 does not cause Global Warming. Thus CO2 emissions are irrelevant and humans are innocent.
    Debate over.