Monthly Archives: July 2008

unreliability of climate models?

A quicky, since I have 20 minutes until I need to leave the house, but a new blogosphere hit has been going around, namely on the Assessment of the reliability of climate predictions based on comparisons with historical time series> by Koutsoyiannis, D., N. Mamassis, A. Christofides, A. Efstratiadis, and S.M. Papalexiou.

In their abstract they say, “we have also retrieved a number of climatic model outputs, extracted the time series for the grid points closest to each examined station, and produced a time series for the station location based on best linear estimation.” This involves spatial interpolation of the GCM outputs to infer values at the points of interest. What the authors do is pick a few long records and compare to the nearest individual grid cell.

Chris has a question: should there be a comparable link between observations at a point and model outputs at neighbouring grid cells? Changes in topography (mountains, slopes influence things), land cover, urban heat factors, and other micro-climatic variables are sure to matter. Not to be rude, but I would guess that the people who have been well receptive of the conclusions of this paper would also say that the stations which the authors use are all horribly contaminated…probably because they seen a picture. I als do not feel that the conclusions that models have little predictive ability over longer-term scales (in time or space) are just as invalid as (what the authors feel) the individual sites, compared to the nearest grid cell. It’s not something we can gather directly from their analysis, and so I’d recommend that the authors do not oversell their results.

For a comparison of various variables from IPCC models to observations since 1990, I’d recommend Rahmstorf et al 2007.

Any insight from anyone else would be good.


Countries agree to cut GHG gases, developing ones not so much

From USA Today

TOYAKO, Japan — The world’s richest countries agreed Tuesday to support a 50% reduction in worldwide greenhouse gas emissions by 2050 — but environmentalists and developing countries denounced the move as a mushy compromise that would do little to stop global warming.

President Bush declared Wednesday that the world’s biggest-polluting countries had made “significant progress” against the threat of global warming after they agreed to work together to fight climate change.

But the agreement, signed here by 17 major economic powers, contained no binding requirements to reduce emissions of the greenhouse gases.

The statement came a day after the Group of Eight industrialized nations — which wrapped up its annual meeting Wednesday at this resort in northern Japan — endorsed the idea of cutting greenhouse gas emissions 50% by 2050. But the G-8 nations didn’t commit to meeting the specific targets and didn’t specify the year from which the cuts would start; Japan wants the start date to be 2008, but European countries want to cut emissions from 1990 levels.

And rising economic powers India and China balked at signing onto the 50% reduction target — though they joined with the G-8 and seven other countries in committing to “combat climate change” in their own ways.

“Each country is doing a bottom-up analysis of what they can achieve,” said White House environmental adviser James Connaughton. President Bush had come up with the idea of inviting “major economies,” including China and India, to work with the G-8 nations of the United States, Japan, Great Britain, France, Germany, Italy, Canada and Russia on fighting global warming. Bush refused to commit the U.S. to specific emissions reduction targets until big polluters including China and India also signed on.

Of course, the United States doesn’t feel like they have to do much. We’re only the #2 country responsible for the amount of excess CO2 in the air today (after the UK). But developing countries like China and India have their own thoughts:

TOYAKO, Japan (AP) — China, India and other energy-guzzling developing nations on Wednesday rejected key elements of a global warming strategy embraced by President Bush and leaders of wealthy nations. And the U.N’s top climate official dismissed the G-8 goals as insignificant.

he “major economies” are the world’s 16 largest-emitting nations, accounting for 80% of the world’s air pollution. The expanded meeting that included all of them was the first time their leaders had sat down together for climate discussions.

But it ended with only a vague reference in their final declaration to a long-term goal for reducing global emissions and a pledge for rich and poor countries to work together. Only a few of the emerging powers — Indonesia, Australia and South Korea — agreed to back the 50% by 2050 reduction target.

The five main developing nations — China, India, Brazil, Mexico and South Africa, who together represent 42% of the world’s population — issued a statement explaining their split with the G-8 over its emissions-reduction goals. They said they rejected the notion that all should share in the 50-percent target, since it is wealthier countries that have created most of the environmental up to now.

“It is essential that developed countries take the lead in achieving ambitious and absolute greenhouse gas emissions reductions,” said the statement.

Chinese President Hu Jintao went a step further in separate remarks. While acknowledging that developing nations must act, he said “developed countries should make explicit commitments to continue to take the lead in emissions reduction.”

Chris thinks that global warming is not going to be solved by finger pointing and the “he started it” game.