Reading sites like Climate Audit and Niche Modeling is a great eye-opener if you want to know where the data comes from that supports the current apocalyptic frenzy around the subject of global warming.
Suffice it to repeat the old saw about “lies, damn lies, and statistics”. The only overall temperature measurements we have are from satellites, and only since 1979. They show that the last ten years have actually seen a cooling trend. Land-based temperature measurements, which go back a hundred years or so, are extremely hard to interpret, due to the fact that most temperature stations are in urban areas, which tend to be hotter than rural areas. Data before a couple hundred years ago is indirect, based on things like ice cores and tree rings. In order to get a reliable picture from that kind of data, you need to make all kinds of initial assumptions about how the data should be interpreted. Then you run the data through an extremely convoluted statistical program. When the tree-ring and ice core data is run through Hanson’s famous program, you get the infamous “hockey stick” graph that shows rapidly rising temperatures for the forseeable future.
The funny thing is, you can run completely random noise through Hanson’s program and it will still output a hockey stick graph.
Anyway, don’t take my word for it:
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.
FullCAM models carbon flows in plants, mulch, debris, soils and agricultural products, using inputs such as climate data, plant physiology and satellite data. I’ve been following the global warming debate closely for years.
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?”
There is no doubt that some parts of the world have been warmer in recent years than in the last century or so. But there is very little reason to believe that those warm spots are part of a global trend, or that they will keep warming. Even in the past thousand years, parts of the world have been much warmer than they are now — the Arctic in the middle ages — and colder — England only 200 years ago.