Guest Post by Willis Eschenbach
In her always interesting blog, Dr. Judith Curry [and Anthony at WUWT] points to a very well-researched article by Bjorn Lomborg, peer-reviewed, entitled “Impact of Current Climate Proposals” (full text).
He has repeated the work that Tom Wigley did for the previous IPCC report. There is a simplified climate model called “MAGICC” which is used extensively by the IPCC. It can be set up to emulate the results of any of the climate models used by the IPCC, including their average results, by merely changing the MAGICC settings. This lets us figure out how much cooling we can expect from a variety of programs that promise to reduce CO2.
The abstract of the paper says (emphasis and formatting mine):
This article investigates the temperature reduction impact of major climate policy proposals implemented by 2030, using the standard MAGICC climate model. Even optimistically assuming that promised emission cuts are maintained throughout the century, the impacts are generally small.
- The impact of the US Clean Power Plan (USCPP) is a reduction in temperature rise by 0.013°C by 2100.
- The full US promise for the COP21 climate conference in Paris, its so-called Intended Nationally Determined Contribution (INDC) will reduce temperature rise by 0.031°C.
- The EU 20-20 policy has an impact of 0.026°C, the EU INDC 0.053°C, and China INDC 0.048°C.
- All climate policies by the US, China, the EU and the rest of the world, implemented from the early 2000s to 2030 and sustained through the century will likely reduce global temperature rise about 0.17°C in 2100.
These impact estimates are robust to different calibrations of climate sensitivity, carbon cycling and different climate scenarios. Current climate policy promises will do little to stabilize the climate and their impact will be undetectable for many decades.
Note that in all cases, these are the optimistic numbers, in which the supposed reductions in CO2 emissions are assumed to continue after 2030 all the way until 2100.
Of particular interest to me was the impact of the Obama War On Coal, or as it is known, the US Clean Power Plan (USCPP). Even if we can implement it, and then assuming we can follow it until 2100, the total reduction in temperature rise is estimated to be 0.013°C.
Now, that’s a bit over a hundredth of a degree Celsius. The problem is, nobody has a good handle on just how small that reduction in temperature actually is, because we have nothing to compare it to. Even fever thermometers only measure to a tenth of a degree. Casting about to rephrase this number in units that might be more understandable than hundredths of a degree, I remembered the old rule of thumb about how much the air cools off as you climb a mountain. Everyone knows that as you go up a mountain, the air gets cooler. The rate at which non-condensing air cools with increasing altitude is called the “dry adiabatic lapse rate”. The rule of thumb states that for every hundred metres higher that you climb, the temperature drops by 1°C.
Now, a human being is typically around 1.7 metres tall, plus or minus. This means that other things being equal, the air at your head is about 0.017°C cooler than the air at your feet. And recall from above that the “impact of the US Clean Power Plan (USCPP) is a reduction in temperature rise by 0.013°C by 2100” …
Which means that after spending billions of dollars and destroying valuable power plants and reducing our energy options and making us more dependent on Middle East oil, all we will do is make the air around our feet as cool as the air around our heads … I am overcome with gratitude for such a stupendous accomplishment.
Now, at this point the advocates of the policy often say something like “Yes, but this is just the first step. Wait until the other nations get so amazed at the damage we’re doing to our own economy that they all want to sign on and do the same”. Of course they don’t put it honestly like that, but their belief is that if the US gets stupid, everyone will follow our lead. I don’t believe it for one minute, no matter how much they SAY that they will come to the party, but let’s imagine that fairy tale to be true.
Well, Lomborg calculated that as well. He used MAGICC to compute the combined effect of the CO2 promises of the whole world, and the answer was 0.17°C of cooling by 2100 in the optimistic scenario, where everyone not only meets their promised reductions but holds to them from 2030 to 2100.
And the number for what Lomborg calls the “pessimistic” scenario, but which might more accurately be called the “realistic” scenario, is a reduction in warming of 0.05°C (see his Table 1).
And this in turn is equivalent to the difference in temperature that you’d get from walking five metres higher on the hillside. You know, like when you say “it’s so hot here, I think I’ll walk up the hill the equivalent of two flights of stairs so I’m five metres higher, and I’ll be cooler by five hundredths of a degree” …
In any case, the MAGICC results are what are used by the IPCC, so there you have it. If everything that the politicians in Paris are promising comes to pass, it will make a difference of between five hundredths and seventeen hundredths of a degree by 2100 … at an astronomical price, billions and billions of dollar globally.
Sigh … an astronomically large price for an unmeasurably small cooling. Freakin’ brilliant. This is what passes for the peak of “responsible” scientific thought these days about the climate, but to me, it’s just the height of temperature folly.
Best of the autumn days to everyone,
AS USUAL: If you disagree with someone, please quote the exact words you disagree with. This lets everyone understand exactly what you are objecting to.
Note: Willis was apparently reading Curry’s article while the WUWT article from Lomborg posted, so I added a link in the first paragraph -Anthony