I DEVOTED six years to carbon accounting, building models for the Australian Greenhouse Office. I am the rocket scientist who wrote the carbon accounting model (FullCAM) that measures Australia's compliance with the Kyoto Protocol, in the land use change and forestry sector.
...
When I started that job in 1999 the evidence that carbon emissions caused global warming seemed pretty good: CO2 is a greenhouse gas, the old ice core data, no other suspects.
The evidence was not conclusive, but why wait until we were certain when it appeared we needed to act quickly? Soon government and the scientific community were working together and lots of science research jobs were created. We scientists had political support, the ear of government, big budgets, and we felt fairly important and useful (well, I did anyway). It was great. We were working to save the planet.
But since 1999 new evidence has seriously weakened the case that carbon emissions are the main cause of global warming, and by 2007 the evidence was pretty conclusive that carbon played only a minor role and was not the main cause of the recent global warming. As Lord Keynes famously said, "When the facts change, I change my mind. What do you do, sir?"
Evans then goes on to list four facts that he believes cast doubt on the idea of anthropometric global warming:
1. Scientists can't find the greenhouse signature (hotspot) in the atmosphere despite repeated attemts. They have now changed to a method which allows them to say "we can't rule out a hotspot"
2. There is no evidence that increased CO2 levels in the atmosphere has raised temperatures. Theory says it should, by how much is debatable, but no one has actually measured it.
3.
The satellites that measure the world's temperature all say that the warming trend ended in 2001, and that the temperature has dropped about 0.6C in the past year (to the temperature of 1980). Land-based temperature readings are corrupted by the "urban heat island" effect: urban areas encroaching on thermometer stations warm the micro-climate around the thermometer, due to vegetation changes, concrete, cars, houses. Satellite data is the only temperature data we can trust, but it only goes back to 1979. NASA reports only land-based data, and reports a modest warming trend and recent cooling. The other three global temperature records use a mix of satellite and land measurements, or satellite only, and they all show no warming since 2001 and a recent cooling.
4. Ice core samples actually show that in previous warming periods increases in Carbon levels trailed increases in temperatures by 800 years. They didn't lead it.
Evans closes, in part, with:
The world has spent $50 billion on global warming since 1990, and we have not found any actual evidence that carbon emissions cause global warming. Evidence consists of observations made by someone at some time that supports the idea that carbon emissions cause global warming. Computer models and theoretical calculations are not evidence, they are just theory.
So that's one view. Then we have Al Gore's latest in which he calles for the US to abandon fossil fuels by 2018, partially for "national security reasons" and partially to prevent climate change.
I can go with the idea of alternative energy for national security. I don't like the idea od Saudi Arabia having a death grip on our policies just because the have oil, but the globa warming stuff as noted above is suspect at best.
Both these guys can't be right and that's what I mean by a disconnect. If we are basing policy on the idea of stopping global warming and the main culprit is really increased solar out put, well... then we are pretty stupid.
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