Last month I visited the San Diego Zoo. The Polar Bear exhibit featured a display showing a shrinking polar ice cap and a bunch of global warming propaganda. Whenever global warming theory is presented as a fact, I get a bit testy.
Sure, the world is warmer and the ice cap has been shrinking….but is it because of carbon dioxide in the atmosphere? Maybe, maybe not.
I personally think particulate air pollution, mostly from China, is more important than carbon dioxide when evaluating Arctic Ice melting. The particulate matter has been making the snow slightly less white. The snow then absorbs heat faster and melts faster. Of course I don’t know for sure….but recent studies support my view. Perhaps the display is older than the new data studies that began surfacing in 2009.
The display doesn’t talk about air pollution, or solar winds, or variations in the Earth’s orbit; just about carbon dioxide, as if that is the only variable worth considering.
And then the display cherry picks data. The exhibit includes a model of the North Pole showing the change in summer melting of ice that begins in the late 1970’s and ends in 2007. 2007 was the peak year in recent history for Arctic Ice melting. Since then the ice has actually been growing. February of 2012 had the 5th lowest February ice accumulation in the 32 year history of the data, still low but way up from 2007.
The National Snow and Ice Data Center provides regular updates at:
Time magazine ran a cover story on global cooling in 1974. In that article the Polar Ice Cap was expanding rapidly and had been expanding for over 20 years. Carbon dioxide has been increasing at a fairly regular rate for the entire 20th century. From 1940 to the mid 1970’s carbon dioxide was steadily rising and the Earth was cooling. Clearly it is not the only variable worth considering.
Let’s return to the Zoo display. Carbon dioxide levels were prominently displayed in a large graph. The most prominent feature of the chart was a label titled Optimum Level. Give me a break. The associated text does say some scientists say the optimum level is…..but the data is displayed so that you notice the optimum level first…and maybe notice the qualifier if you read the fine print.
The notion that 1) there is an optimum level, 2) we know that level is and 3) that level is a constant value must be at least a bit speculative. I wonder if that was a Scientific Wild Ass Guess (SWAG) or just a wild ass guess…either way it was a guess.
There is also a chart displaying carbon dioxide levels in our recent past. The chart begins just after the end of the medieval warming period. Data from Antarctic ice cores show the relationship between carbon dioxide and temperature that goes back 700,000 years. The Zoo decided to limit the display to the last 1000 years.
The notion that the recent past is more important that the rest of the 2.5 million year old Ice Age Cycle we live in seems a tiny bit presumptuous. Is it wise to concentrate on the last 50 years of the last 1000 when trying to evaluate climate?
An honest evaluation of historic data graphically demonstrates the wild natural variation in climate. It was 6 degrees Celsius warmer 130,000 years ago and 10 degrees Celsius cooler 20,000 years ago and sudden rapid change within a cycle is fairly common. Why are we worrying so much about an increase of less than 1 degree Celsius in the 20th century, a change that is not spectacular historically?
The people that run the San Diego Zoo are smart folks, they know about the ice age cycle we live in. Just about everybody in climate science knows that we do not live in a world that has static climate. And yet the scientific community is constantly presenting data that presumes that the world would be static were it not for man-made carbon dioxide.