Climate change update

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Climate change forcing graph shows the impacts of various elements on global temperature. Courtesy of Dr. Kerry Emanuel MIT.

We hit -21 in the Twin Cities this week for the coldest temperature in 5 years. So the whole "global warming" thing is over right?

Not exactly. I wish I had a dollar for every time somebody says something about climate change that either refers to WEATHER or misstates the science of climate change.

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At the risk of starting a few fires on a cold January day in Minnesota, let's bust a few myths about climate change right here.

1) We will still have winter. Sometimes it will even be really, really cold.

2) We will still have "below average" years. In fact for those who say we are now "cooling" let's remember that we have had the 10 warmest years on record since 1997. During that stretch we would have expected 6 above average and 6 below average years statistically speaking. Do you have any idea what the odds are of having the 10 warmest years on record, in one decade?

3) 2008 was above average globally. In fact it was the 10th warmest year on record. Just because it was slightly cooler than in previous years does not mean we are in an overall long term cooling trend. What is really surprising is that we have not had a below average year globally in over a decade.

4) Variations in our sun and solar output have been factored in to climate change models. The graph above (sorry for the quality) shows how greenhouses gasses have much greater climate forcing than volcanic, solar or other variables.

5) Urban heat island effects are accounted for, and though a few stations may be marginally effected by their location they are such a small part of the record as to be insignificant. The vast majority of data on climate change comes from ice cores, tree rings, deep lake sediments and other sources independent of our surface based temperature network.

6) CO2 has always varied naturally, but the rate of increase in the past 50-100 years is far higher than at any time in the past. That's the human "fingerprint" on global atmospheric changes.

There really is no debate that the planet is getting dramatically warmer. The real questions are; what are the specific and regional effects going to be? How will we adapt to climate change? What policies for reducing greenhouse gasses make scientific and economic sense? Will we be good stewards of our planet and environment?

We will talk plenty more about climate change in the coming months and years. For right now if you really want to spend some quality time learning what the best science in the world says about climate change, spend a quality weekend reading through parts of the IPCC report.

Enjoy the milder temperatures as we emerge from the deep freeze!

PH