Following my blog post titled 'Richard Lindzen on Hockey Sticks' there was some discussion about Richard Tol's views on various issues relating to economics and the Intergovernmental Panel on Climate Change. Various commentators at the thread where quoting Dr Tol in support of their position. Dr Tol has provided the following response:
"Ian Castles and William Connelley had a discussion about what I said and did not say. Here is my version.
If one assumes convergence of per capita income, and one measures income in purchasing power parity (PPP) exchange rates, then projections of global carbon dioxide emissions are lower than in case one measures income in market exchange rates (MER).
This is the original Castles and Henderson critique of IPCC SRES.
However, emission intensities are also assumed to converge, which partly offsets the above effect.
This was pointed out by Manne and Richels, and by Alfsen and Holtsmark, while Castles and Henderson admitted their initial omission.
As a result, switching from MER to PPP reduces global carbon dioxide emissions, but by an amount that is small compared to the uncertainty about future emissions.
That is, if one is interested in long-term, global climate change, the Castles and Henderson critique is of minor importance.
However, one should worry about the fact that the IPCC, first, made a very basic error and, second, is unable to admit that and correct its way.
If one is interested in climate policy, the Castles and Henderson critique does matter, because the small drop in global emissions is almost entirely due to China and India. The OECD thus shoulders a larger part of the responsibility. The argument of the US Senate, that climate policy without China makes no sense, cuts less wood.
If one is interested in climate impacts, the Castles and Henderson critique does matter, because projected economic growth is slower in developing countries, and vulnerability is larger as a result. Although warming would be slower, impacts may in fact be larger.
If one is interested in regional climate change, the Castles and Henderson critique does matter, because future emissions of sulphur would be different as well, probably higher.
In sum, Castles and Henderson raise five issues, only one of which is of minor importance.
By the way, my reading of the state-of-the-art in economics is that (a) income should be measured in PPP nor MER; (b) there is neither theoretical nor empirical support for the assumption of unconditional income convergence; (c) there is limited empirical support for the assumption on energy intensity convergence.
Richard Tol"
Dr Tol is the Michael Otto Professor of Sustainability and Global Change in the Departments of Geosciences and Economics at the Hamburg University, Hamburg, Germany.
Hello
nice site
Thanks Richard. Actually I felt you points were quite clear in the first version I read and there was really no need for the confusions.
As I read you, I understand that a lot more sophistication could go into economic modelling aspects of carbon dioxide emmissions, and this could yield a stronger platform for policy decisions.
cheers DaviT T
My second-to-last sentence should have read:
In sum, Castles and Henderson raise five issues, one of which is of minor importance, while the other four do matter.
I did not say that China's emissions are not important. I only said that per Castles and Henderson, China's future emissions may be lower than the IPCC would have us believe.
Sorry, wrong thread!
Al Gore had Ohio speechless;
"Two hundred years ago this summer, at the sunrise of America's first full century, veterans of the American Revolution came here and founded Smith County. In their minds' eye, the very idea of what America could become was still then a barely discernible horizon."
"(my father) saw a horizon in which his black and white constituents shared the same hopes in the same world.... His last election was lost -- but his conscience won."
"Each of us has our own sense of the next, finer horizon."
"America always looks forward, to the next horizon."
"Just visible within a generation's journey is a new horizon"
"And I know that with our history as our rudder and our ideals as our compass, we can reach our new horizon."
"And I see on the horizon an America where people with disabilities are fully respected for the abilities they have, everywhere in this land."
"Come with me toward America's new horizon. Across that horizon stands the promise of our common values and prosperity - of strengthening every family, lifting every child, leveling every barrier, leaving no one behind."
"Here, at the center of my home town, in the heart of America, in the midst of the people I love - that is the new horizon I see"
http://www.4president.org/speeches/gore2000announcement.htm
And the proof, Digger, of your little outburst is what exactly?
Ian Castles has a nasty habit of stepping over the squashed bananas to display the cherries. If you read further of gis various sources you invariably stumble across other statements that do not support him. Raise them though, and he'll quote extensively and so profusely and boorishly that you'll regret that you did because his responses are heavily engineered to rebuff and obfuscate, not learn or share. Ian knows all, his footwork is practiced, his sword gleaming and his stance determined.
Rather than waste time in a frontal with the nine-headed beast we can quietly acknowledge why his tiresome and repetitive arguments have generally won the reception they have. We can also be clear why he has found the dire need to move from specific criticisms of particular assumptions to more general attacks of the broader IPCC process. His aim is to discredit the IPCC and to argue against AGW. Nothing more noble than that. Thus, having jabbed successfully, he now expands in a series of flank attacks to encircle all related issues.