Climate Impacts of Waxman-Markey (the IPCC-based arithmetic of no gain)
Editor Note: Using mainstream models and assumptions, Mr. Knappenberger finds that in the year 2050 with a 83% emissions reduction (the aspirational goal of Waxman-Markey, the beginning steps of which are under vigorous debate), the temperature reduction is nine hundredths of one degree Fahrenheit, or two years of avoided warming by 2050. A more realistic climate bill would be a fraction of this amount. The author will respond to technical questions on methodology and results and invites input on alternative scenarios and analyses.
“A full implementation and adherence to the long-run emissions restrictions provisions described by the Waxman-Markey Climate Bill would result only in setting back the projected rise in global temperatures by a few years—a scientifically meaningless prospect.” (from below)
The economics and the regulatory burdens of climate change bills are forever being analyzed, but the bills’ primary function—mitigating future climate change—is generally ignored.
Perhaps that’s because it is simply assumed.
After all, we are barraged daily with the horrors of what the climate will become if we don’t stop emitting greenhouse gases into the atmosphere (the primary focus being on emissions from the combustion of fossil fuels). So doing something as drastic as that proposed by Waxman-Markey—a more than 80% reduction of greenhouse gas emissions from the United States by the year 2050—must surely lessen the chances of climate catastrophe. Mustn’t it?
But if that were the case, why aren’t the climate impacts being touted? Why aren’t Representatives Waxman and Markey waving around the projected climate success of their bill? Why aren’t they saying: “Economics and regulations be damned. Look how our bill is going to save the earth from human-caused climate apocalypse”?
That reason is that it won’t.
And they know it. That is why they, and everyone else who supports such measures, are mum about the outcome.
The one thing, above all others, that they don’t want you to know is this: No matter how the economic and regulatory issues shake out, the bill will have virtually no impact on the future course of the earth’s climate. And this is even in its current “pure” form, without the inevitable watering down to come.
So discussion of the bill, instead of focusing on climate impacts, is shrouded in economics and climate alarm.
Getting a good handle on the future climate impact of the proposed Waxman-Markey legislation is not that difficult. In fact, there are several ways to get at it. But perhaps the most versatile is the aptly named MAGICC: Model for the Assessment of Greenhouse-gas Induced Climate Change. MAGICC is sort of a climate model simulator that you can run from your desktop (available here). It was developed by scientists at the National Center for Atmospheric Research (primarily by Dr. Tom Wigley) under funding by the U.S. Environmental Protection Agency and other organizations. MAGICC is itself a collection of simple gas-cycle, climate, and ice-melt models that is designed to produce an output that emulates the output one gets from much more complex climate models. MAGICC can produce in seconds, on your own computer, results that complex climate models take weeks to produce running on the world’s fastest supercomputers. Of course, MAGICC doesn’t provide the same level of detail, but it does produce projections for the things that we most often hear about and care about—for instance, the global average temperature change.
Moreover, MAGICC was developed to be used for exactly the purpose that we use it here—the purpose for which Representatives Waxman and Markey and everybody else who wants a say in this issue should be using it. That purpose is, according to MAGICC’s website, “to compare the global-mean temperature and sea level implications of two different emissions scenarios” —for example, scenarios both with and without the proposed legislative emissions reductions.
So that is what we’ll do. We’ll first use MAGICC to produce a projection of global average temperature change through the 21st century under two of the Intergovernmental Panel on Climate Change’s future emissions scenarios (which assume no explicit policy implementation). The two are: a mid-range emissions scenario (SRES A1B for those interested in the details) and a high-end emissions scenario (SRES A1FI). Then, we’ll modify these IPCC scenarios by entering in the emissions reductions that will occur if the provisions outlined in the Waxman-Markey Climate Bill are fully met (leaving aside whether or not that could be done). Basically, Waxman-Markey calls for U.S. emissions to be reduced to 20% below the 2005 emissions level by 2020, 42% below 2005 levels by 2030, and 83% below 2005 levels by 2050. We’ll assume that U.S. emissions remain constant at that reduced value for the rest of the century. We’ll then use MAGICC to produce temperature projections using these modified scenarios and compare them with the original projections.*
And here is what we get all rolled into one simple figure.
The solid lines are the projections of the change in global average temperature across the 21st century from the original IPCC A1FI (red) and A1B (blue) high and mid-range emissions scenarios, respectively (assuming a climate sensitivity of 3ºC). The dotted lines (of the same color) indicate the projected change in global average surface temperature when the emissions reductions prescribed by Waxman-Markey are factored in.
By the year 2050, the Waxman-Markey Climate Bill would result in a global temperature “savings” of about 0.05ºC regardless of the IPCC scenario used—this is equivalent to about 2 years’ worth of warming. By the year 2100, the emissions pathways become clearly distinguishable, and so to do the impacts of Waxman-Markey. Assuming the IPCC mid-range scenario (A1B) Waxman-Markey would result in a projected temperature rise of 2.847ºC, instead of 2.959ºC rise— a mere 0.112ºC temperature “savings.” Under the IPCC’s high-emissions scenario, instead of a projected rise of 4.414ºC, Waxman-Markey limits the rise to 4.219ºC—a “savings” of 0.195ºC. In either case, this works out to about 5 years’ worth of warming. In other words, a full implementation and adherence to the emissions restrictions provisions described by the Waxman-Markey Climate Bill would result only in setting back the projected rise in global temperatures by a few years—a scientifically meaningless prospect. (Note: I present the results to three significant digits, not that they are that precise when it comes to the real world, but just so that you can tell the results apart).
Now, various aspects of the MAGICC model parameters can be tweaked, different climate models can be emulated, and different scenarios can by chosen. And different answers will be obtained. That is the whole purpose of MAGICC—to be able to examine the sensitivity of the output to these types of changes. But if you take the time to download MAGICC yourself and run your own experiments, one thing that you will soon find out is: No matter what you try, altering only U.S. emissions will produce unsatisfying results if you seek to save the world by altering its climate.
We have calculated only the climate impact of the United States acting alone. There is no successor treaty to the Kyoto Protocol to bind other countries to greenhouse gas emissions reductions. But, truth be told, the only countries of any real concern are China and India. The total increase in China’s emissions since the year 2000 is 50 percent greater than the total increase from rest of the world combined and is growing by leaps and bounds. And consider that India carbon dioxide emissions haven’t started to dramatically increase yet. But it is poised to do so, and an Indian official recently stated that “It is morally wrong for us to agree to reduce [carbon dioxide emissions] when 40 percent of Indians do not have access to electricity.”
Without a large reduction in the carbon dioxide emissions from both China and India—not just a commitment but an actual reduction—there will be nothing climatologically gained from any restrictions on U.S. emissions, regardless whether they come about from the Waxman-Markey bill (or other cap-and-trade proposals), from a direct carbon tax, or through some EPA regulations.
This is something that should be common knowledge. But it is kept carefully guarded.
The bottom line is that a reduction of U.S. greenhouse gas emissions of greater than 80%, as envisioned in the Waxman-Markey climate bill will only produce a global temperature “savings” during the next 50 years of about 0.05ºC. Calculating this isn’t all that difficult or costly. All it takes is a little MAGICC.
[Note: Be sure not to miss Part II of this analysis, where I take a look at what happens if the rest of the world were to play along.]
* Assumptions Used in Running MAGICC
There are many parameters that can be altered when running MAGICC, including the climate sensitivity (how much warming the model produces from a doubling of CO2 concentration) and the size of the effect produced by aerosols. In all cases, we’ve chosen to use the MAGICC default settings, which represent the middle-of-the-road estimates for these parameter values.
Also, we’ve had to make some assumptions about the U.S. emissions pathways as prescribed by the original IPCC scenarios in order to obtain the baseline U.S. emissions (unique to each scenario) to which we could apply the Waxman-Markey emissions reduction schedule. The most common IPCC definition of its scenarios describes the future emissions, not from individual countries, but from country groupings. Therefore, we needed to back out the U.S. emissions. To do so, we identified which country group the U.S. belonged to (the OECD90 group) and then determined the current percentage of the total group emissions that are being contributed by the United States—which turned out to by ~50%. We then assumed that this percentage was constant over time. In other words, that the U.S. contributed 50% of the OECD90 emissions in 2000 as well as in every year between 2000 and 2100. Thus, we were able to develop the future emissions pathway of the U.S. from the group pathway defined by the IPCC for each scenario (in this case, the A1B and the A1FI scenarios). The Waxman-Markey reductions were then applied to the projected U.S. emissions pathways, and the new U.S. emissions were then recombined into the OECD90 pathway and into the global emissions total over time. It is the total global emissions that are entered into MAGICC in order to produce global temperature projections—both the original emissions, as well as the emissions modified to account for the U.S. emissions under Waxman-Markey.