So Britain made climate change, or global warming, or whatever you want to call it, a big topic at the latest G8 meeting.

Now I pride myself on being scientifically literate, but for the life of me, I don't understand why global warming is considered so horrible or so urgent. And I don't understand why so many scientists are up in arms about it. Here is the Wikipedia entry on Global Warming.

It states that: Over the past century or so the global (land and sea) temperature has increased by approximately 0.6 ± 0.2°C.

Okay. Regarding Carbon Dioxide levels in the atmosphere it says: At the same time, atmospheric carbon dioxide has increased from around 280 parts per million in 1800 to around 315 in 1958 and 367 in 2000.

Okay. It also says model predict a change in temperature for the next hundreds years within "a range of 1.4°C to 5.8°C".

Okay again. What does this all mean? Japan submerged underwater in a few decades? Mass hysteria? Dogs and cats living together?

I'm no geologist, but my understanding is that much greater fluctuations of both temperature and CO2 have occurred throughout Earth's history.

Here is a graph of CO2 levels and temperature for the past 600 million years:



I found it on this site, which seems a little specious, but if it's wrong, will someone please point me to a more accurate source?

It notes that CO2 levels were 7000 ppm in the Cambrian and that the average global temperature was near 22°C. It shows today's average global temperature at around 12°C, and gels with the Wikipedia article with CO2 around 315ppm.

So then, even with all of the human activity, the earth is a hell of a lot cooler than at most times during the past 600 million years, with far lower levels of CO2. Life has flourished and diversified during that time. Land and water formations have changed, but that's natural.

Even according to the greatest amount of change listed in the article, we would still be far below anything like historical highs for CO2 and temperature, even if we kept cranking out the fossil fuel emmissions like we currently are.

This doesn't necessarily mean we shouldn't cut fossil fuel emissions. But air quality and reliance on foreign sources of oil seem like far more compelling reasons to find alternative energy sources than global warming, which seems to me to be a very chicken little perspective.

Can somebody tell me where I'm wrong on this one?