Sunday, July 01, 2007

Game Plan by Jim Manzi : A Response

I didn't agree with everything that jim had written...

My response to Jim Manzi's Article can be downloaded from here.

My main problem with what Jim Writes is that it misrepresents the science as i see it. For example, the urgency can bee seen if we consider the background article bellow entitled 'dangeroud human-made interference with climate' where 450ppm co2e is considered to be dangerous...what does that mean? Well the UK govornments recent climate bill, with a headline 60% cut by 2050 is heading in the direction of 750-800ppm co2e according to the UK's to climate policy/science institute The Tyndall Centre! So this is not a small problem, and arguing against something as comprehensive as a cap and trade system it seems to me is the 'fall-back' position of climate skeptics.

1.Climate Change isn't real.
>Now we have observed data rather than projections.

2. Climate Change isn't cause by humans.
> Four IPCC reports later this is old hat.

3. Climate Change is caused by humans but it is good.
>Tell that to Katrina victims or people in Darfur.

4. Climate Change is caused by humans and it is bad but there is nothing we can do about it.
>Nicholas stern slaughtered this one.

5. The all new climate skeptics position: It is real, it is caused by us, it isn't good, we can do something about it BUT it's not that bad all these folks are alarmists!


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At 5:02 PM, Anonymous Anonymous said...

Thanks for your detailed and thoughtful commentary on my article.

I’ll try to respond to a number of the questions that you raise:

1. You ask for a source for the assertion that the temperature impact of a doubling of atmospheric concentration of CO2 in the absence of feedbacks would be on the order of 1C. Here are a couple of standard references that combine accessible language with descriptive completeness (please note that one of these is RealClimate, which aggressively supports the AGW position):

You can actually calculate this equilibrium sensitivity yourself with this simple FORTRAN-based calculator provided by the University of Chicago. (The calculations are simple and transparent, since we are by the definition of the stated problem, avoiding what makes CGMs complex – namely feedbacks):

2. You say that if climate models have been accurate in replicating past conditions, then there is no reason to believe that they won’t be accurate in predicting future conditions. But there is a long, sorry history of models of complex systems that can replicate historical behavior but fail to accurately predict in the field. This problem is especially acute for models with a very large number of parameters which must be established without direct reference to known physical laws and for which falsification tests are exceedingly difficult to execute, i.e., Global Climate Models. Note that no CGM has ever demonstrated validated predictive accuracy for the temperature impact of increased carbon concentration on a multi-decadal timescale. Further note that this doesn’t mean that they are “wrong”, just that they are not proven, and therefore their results need to be taken with a large dose of salt.

3. You question whether China and India will agree to material emissions abatement. While it is impossible to predict with certainty what any group of human beings will do, I believe that it is a prudent belief that neither of these countries will sacrifice economic growth. The government of China has explicitly stated that they will make only those accommodations to climate change that do not reduce economic growth – and I would do exactly the same thing in their place. Note that Europe and the US can reduce emissions all we want, but unless the developing world goes along such a mitigation strategy will not address the problem, if one should develop (as I’ve said earlier, of course, it is uncertain that one would).

4. You say that the loss of the Greenland Ice Sheet “…is now considered almost inevitable. The timing of the disintegration is being debated”. Anybody can “consider” anything they like to be “almost inevitable”, but there is no proven scientific principle that demonstrates this at all. The only thing that science, in the form of the IPCC for example, can say is that no models (which are themselves unproven) call for this to happen in the next hundred years. We don’t know (in any scientific sense of the word “know”) what is going to happen to the GIS.

In my experience, both sides in this debate have an enormous tendency to exaggerate their level of certainty in predicting future climate developments. Here is how I would summarize my position on the science:

• CO2 absorbs and re-directs infrared but not shorter-wavelength radiation.
• Therefore, all else equal, more CO2 molecules in the atmosphere will make it hotter.
• But, all else is not close to equal. Any change, including pumping out more CO2, will kick off an incredibly complicated set of feedback effects.
• No climate model has ever demonstrated a validated capability to accurate predict the multi-decadal impact of increased CO2 concentration.
• Therefore, while we can reasonably expect that we will experience some increase in temperature as a result of CO2 emissions, this impact could plausibly range from negligible to severe.

5. You (correctly) note that the Stern Report asserts that the cost of inaction on emissions outweighs the cost of action. As I describe in my article, even if we assume away the problems of uncertainty in our climate projections (what is being discussed in points 1, 2 and 4) and further assume away the China – India problem (point 3), this conclusion is contrary to virtually all other economic analyses other than the Stern Report, because the Stern Report assumes both the most pessimistic assumptions about potential climate impacts and a discount rate of approximate 0%. Look at the scholarly reaction to the Stern Report among serious analysts of this problem. I won’t try to put in all the reference links here, but just google [“Stern Report” Yale Harvard].

If you don’t want to wade through the econometric analysis, think of this in common-sense terms. The IPCC estimate for the economic impact of a 4C increase in temperatures in 1 – 5% of global GDP (obviously, something like this is at best a SWAG). Under IPCC Scenario A1B, global warming by about 2100 will be 2.8C, we won’t even get to 4C until well into the 22nd century. So, ignoring the hubris of us trying to manage the economy and climate of the 22nd century today, this means that the costs we would avoid would be on the order of 3% of GDP 100 – 200 years from now. You just can’t justify a huge loss in economic output today in return for that kind of benefit. The idea that we can get a free lunch by passing a law that says “you can’t use more than X units of carbon”, and this will somehow not cost us economic output today because somehow all of the market participants were too stupid to see that they had lots of opportunities they were not otherwise pursuing but now will strikes me as really, really wishful thinking.

The painful reality is that we have to try to make investments today that protect us against future risks, many of which – including global warming – are unquantifiable, in way that balances many considerations. As I describe in the article, this is the problem with the practical application of the Precautionary Principle.

I know I didn’t get into every point you made, but tried to focus on those that seemed most important. Overall, we all share the same world, so this doesn’t seem to me like a debate where there should be “sides”.

Again, thanks for taking the time to go through my article in such detail; interaction like this almost always improves conclusions.

Best regards,
Jim Manzi


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