Contributed by Robert Lyman © May 2017
In a story published two days ago in the Independent, a U.K. newsmagazine, Seth Berenstein reported on the claims of a group of scientists, including Michael Oppenheimer of Princeton University, about the possible effects of the United States withdrawing from the December 2015 Paris agreement on global warming. Oppenheimer is quoted as saying that “one expert group” (unidentified) ran a worst case computer simulation of what would happen if the U.S. does not curb greenhouse gas emissions but all other countries meet their targets. It found that “America would add as much as half a degree of warming (0.3 degrees Celsius) to the globe by the end of the century.”
“Another computer simulation team put the effect of the U.S. pulling out somewhere between 0.1 and 0.2 degrees Celsius.”
Wow! As a matter of fact, the Paris Agreement contains no targets. It is a “best efforts” political commitment to constrain the growth in global GHG emissions by amounts to be set by each country in a series of five-year plans. The first five-year plans were estimated to reduce eventual warming (if one believes the models) by about .015 degrees. Even those emissions reductions were contingent on the industrialized countries giving at least $100 billion per year to the developing countries to finance their programs. The developing countries have since said that they need at least $300 billion a year and the industrialized countries have not even come up with $40 billion over five years.
The thesis that all the other countries of the world would, absent the U.S. participation, go on to reduce emissions by the amounts envisioned by U.N. bureaucrats is baseless anyway. The U.N. claims that global emissions will have to be cut in half from today’s levels by 2050. All the authoritative sources on global energy supply, demand and emissions project that, instead, emissions will grow by 40% or more by 2050.
So, under an unrealistic scenario based on questionable modeling and inaccurate assumptions about what the rest of the world will do, the so-called experts are projecting that the U.S. withdrawal from the Paris Agreement could affect global temperatures by somewhere between 0.1 and 0.3 degrees Celsius 83 years from now. What a catastrophe!
“Oppenheimer is quoted as saying that “one expert group” (unidentified) ran a worst case computer simulation of what would happen if the U.S. does not curb greenhouse gas emissions but all other countries meet their targets”.
<- They are not simulations. They are models. There's a big difference. We're not able to simulate earth's climate. We are very far from having suitably fast computers to do. So the models:
1) only consider a few things : 3 or so, important to climate when, in fact there are many more,
2) take very granular readings (e.g. a "point" is the equivalent of a hundred cubic km of atmosphere, or so, and
3) at many places, in the model, where one might want to simulate the climate scientist uses parameterizations instead. Some important things can not be simulated at all (fluid mechanics), but must be parameterized.
“In sum, a strategy must recognise what is possible. In climate research and modelling, we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible.”
IPCC Working Group I: The Scientific Basis, Third Assessment Report (TAR), Chapter 14 (final para., 14.2.2.2), p774.