from MasterResource Website
The IPCC-Based Arithmetic of No Gain
May 6, 2009
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,
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:
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 (EPA) 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,
...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:
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 Change 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,
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.
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.
Yesterday’s MasterResource post (Part I above) looked at the potential climate impacts of the proposed Waxman-Markey Climate Bill. But I limited my analysis to only U.S. actions - after all, Waxman-Markey can’t mandate international man-made greenhouse gas reduction timetables.
But, what would happen if the rest of the world wanted to join in?
The Bottom Line
The ability of the industrialized world, through emissions reductions alone, to impact the future course of global climate is minimal.
...all limited their emissions of greenhouse gases according to the schedule laid out under Waxman-Markey - a monumental, unexpected development - it would, at most, avoid only a bit more than one-half of a °C of projected global warming (out of 4.5°C - or only about 10%).
And this is under worst-case emissions assumptions; middle-of-the-road scenarios and less sensitive climate models produce even less overall impact.
To make any significant in-roads to lowering the rate (and thus final magnitude) of projected global temperature rise, the bulk of the emissions reduction needs to come from other parts of the world, primarily,
The problem is, is that these governments are not inclined to restrict the energy usage of its citizens - in fact, they either are in the process of, or are soon hoping to, significantly expand the amount of energy available to their (growing) populations - and in the process, subsuming all potential emissions savings from the (current) industrialized world.
If supporters of large greenhouse gas emissions restrictions were really interested in “saving the world,” they would be putting all of their effort into getting China and India to buy into their plan - and then turning to the U.S. up in mop up duty.
As it stands now, they are talking to the wrong end of the horse.
Over the first decade of the 21st century, global carbon dioxide emissions have been growing a pretty good clip - in fact, they’ve been growing at a rate which exceeds the projected rate from the most extreme scenario envisioned by the Intergovernmental Panel on Climate Change (IPCC).
It is also the scenario which, when fed into the world’s climate models, produces the greatest warming by the end of the century - about 4.5ºC (although the world abounds with observations that suggests that this temperature rise is overblown, but that is the subject of a different analysis).
The question I want to explore here, is,
And more specifically, who are “we”?
The proposed Waxman-Markey Climate Bill is aimed to reduce the projected rise in global temperature. This bill calls for a reduction in greenhouse gases from the United States according to the following schedule - a 20% reduction (below the 2005 emissions level) by the year 2020, a 58% reduction by 2030 and a 83% reduction by 2050.
So, let’s take “we” to be Americans bound by the emissions reduction schedule laid out under Waxman-Markey and see what effect that “we” would have on the projected global temperature increase if “we” followed the Waxman-Markey plan.
Then, we’ll look at what would happen if “we” were able to get other parts of the world to go along with the plan.
The extreme IPCC scenario is the A1FI scenario and is described as a fossil-fuels intensive scenario of a,
What this all means in terms of the IPCC’s vision of future CO2 emissions is shown in Figure 1.
Projected carbon dioxide emissions
from four country groupings as defined by the IPCC’s A1FI scenario.
For a description of the country groupings, see the text.
(source: IPCC SRES)
The IPCC breaks the world down into four general classifications:
As can be seen in Figure 1, the emissions from each of the groups increase, with most of the increase in the first half of the century coming from the ASIA.
In the last few decades of the second half of the 21st century, the IPCC projects the emissions from the OECD90 countries to quickly ramp upwards, despite slowed growth or even declines among other groups and despite little population growth. This seems like an odd expectation, but I digress…
Now, what I am going to do, through the help of MAGICC (a simple climate model which was developed to emulate the large-scale output of more complex climate models and which was designed to explore the impacts of different emissions scenarios on projected global temperatures), is show you what happens to future global temperature projections if the Waxman-Markey emissions limitation provisions were adopted (and adhered to) by the U.S. And while I’m at it, I’ll take you through the impacts of the adoption by the other regions as well.
Figure 2 is the same as Figure 1, except that I have adjusted the future OECD90 emissions to account for a reduced contribution from the U.S. assuming we stick to the Waxman-Markey emissions schedule.
Same as Figure 1, except the original OECD90 pathway
(dotted pink line) has been modified to account for
the U.S. adherence to the Waxman-Markey emissions schedule (solid pink line).
Figure 3 shows what happens to global temperature projections when the MAGICC model is run with the original A1FI emissions pathways (shown in Figure 1) as well as when it is run under the modified A1FI scenario to include U.S. reductions (shown in Figure 2).
The net result on the projected future global temperatures of a full adherence to the stipulations of the Waxman-Markey Climate Bill is a temperature “savings” of 0.06ºC by the year 2050, increasing to about 0.20ºC by the end of the century.
Projected global temperatures under the A1FI scenario (blue)
and the A1FI scenario modified for a U.S. adherence to
the Waxman-Markey emissions reductions schedule (red).
So, there you have it - going it alone, the U.S. succeeds at only managing to knock off two-tenths of a global temperature rise projected to be nearly 4.5ºC by 2100. Not a whole lot of bang for the buck.
So, clearly we (Americans) need a little, er, a lot of help.
In Figure 4, I depict what happens to the A1FI emissions pathways if every country of the world decided that the plan drawn up by Representatives Waxman and Markey was something that it could not live without and joined in the effort.
Most notably, instead of the rapid rises in ASIA emissions that are projected to occur through the half of the 21st century, the emissions there top out by 2010 and decline sharply thereafter - despite a growing population and rapid industrialization - that’ll be a neat trick to pull off!
Same as Figure 1, except that all groups adhere to
the Waxman-Markey emissions reduction schedule.
Dotted lines are the original A1FI pathways, solid lines are the modified pathways.
Figure 5 shows the projected global temperatures with the different country groups signing on (i.e. MAGICC run with the modified emissions scenario depicted in Figure 4).
Projected global temperatures under the A1FI scenario (blue)
and the A1FI scenario modified for an adherence to the Waxman-Markey
emissions reductions schedule by all countries in the world in succession.
The top curve in Figure 5 (the greatest temperature rise) is projected to occur under the unfettered A1FI scenario.
The bottom curve (the least temperature rise) occurs with everyone on-board. The curves in the middle show who contributes what.
The U.S. acting alone under Waxman-Markey (as we have seen) reduces the projected global temperature rise by the year 2100 by 0.195ºC, if the rest of the OECD90 countries come along, the reduction increases to 0.402ºC - still less than 10% of the total projected rise.
Even with the help of the REF countries, we only get a reduction of 0.602ºC. When the temperature rise really starts to show a decent slowdown is with the cooperation of the ALM countries (a reduction 1.241ºC). And, of course, the biggest impact, nearly as large as everyone else combined, comes from the ASIA countries.
If they alone reduce emissions in line with Waxman-Markey suggestions, they will produce a 1.129ºC decline, and when acting along with everyone else they bring the total temperature reduction to 2.37ºC - a rise that is more than 50% smaller than projected under the original A1FI scenario.
Nothing to sneeze at.
(Again, let me stress that I am describing the impacts on projected global temperatures. There is growing evidence that actual global temperatures are not evolving the way projections indicate that they should. So, the degree to which these temperature projections described above reflect what really will happen in the future, is far from certain.)
So, the key to producing a meaningful change in the course of projected global temperatures is to make sure that those countries of the world which are projected to have the greatest contributions to future emissions growth - primarily the countries in the ALM and ASIA group - take the actions to insure that those growth projections are not met.
The United States has an extremely limited direct role to play in projected future global climate - internal emissions reductions do virtually nothing.
So, plans like the Waxman-Markey Climate Bill really don’t serve to change the climate in and of themselves. Instead, their purpose is to attempt to spur technological innovation and set an example as to what can be done to reduce emissions - with Americans serving both as the experimenters and the guinea pigs.
It is not the climate impact of our experiment that is of any significance, but instead it is the tools that we may develop in attempting to achieve major emissions reductions, for the only truly effective course of action we have available to us in attempting to control the future course of global climate is to tell the rest of the world what to do and how to do it.
Let’s hope they are agreeable - for “we” (Americans) are setting ourselves up to take a great risk for which the outcome, both internally and externally, is far from certain.