Tuesday, July 08, 2008

 

Well Not Exactly Global


Since we are in (deeply in) one of the 20 or so interglaciations which have occurred regularly over the last couple of million years, and coming out of a mini ice age (which followed the Maunder and Dalton Minimums), it is not surprising that the glaciers which covered all of Canada and a lot of the Rocky Mountains (and New York City) just 12,000 years ago, are continuing to shrink. Nor is it any evidence of Global Warming Climate Change caused primarily from anthropogenic greenhouse gasses (mainly CO2). A rooster may make a lot of noise just before the sun rises (or seems to) each morning, but that doesn't mean the rooster causes the sunrise.

Just so, there are indeed higher concentrations of atmospheric CO2 over the last century and almost certainly warming of just over a degree and a half F during that same period, but that doesn't mean CO2 is causing the warming (although only a fool would deny that it contributes some little bit). The Vostok ice core record indicates that CO2 follows a rise in temperature over the last 400,000 years. No reason to believe it isn't the same now.

Because the climate and daily weather are more complex than we can yet begin to understand, we can barely predict what the weather will be like a month from now. Evidence of this complexity is the fact that, despite the warming, all the glaciers on Mount Shasta in Northern California have been growing. Who predicted that 20 years ago? Anyone? Anyone? Bueller?

No one is the true answer.

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"It's a bit of an anomaly that they are growing, but it's not to be unexpected," said Ed Josberger

They should measure them after this summer. Very little snowfall in CA this winter.

So if the tempurature raised 1.8F per century, in 1000 years that would be an 18F mean rise.

You are the expert: is that not unprecedented?
 
No expert I, although I have had an interest since grad school. There is no record of a thousand year steady rate rise. The temperature goes up for a while and then it goes down for a while. That's normality; that's reality. It's been warmer than now--6K years ago, 2k years ago and 1K years ago, and it's been colder--12K years ago, 1.5K years ago and 400 years ago. Even in the past 100 years the rise in termperature in the 20s and 30s was followed by a cooling in the 70s. The increase in the 90s looks to many like it will be followed by cooling not just the next 10 years but for decades to come. Perhaps the interglaciation will end and a new ice age start. No one knows. The weather and climate are too complex for us to predict accurately more than a few days ahead.
 
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