Thursday, November 08, 2012

Scientific American warns of out-of-control "feedback loops" from climate change


The November 2012 issue of Scientific American has an important article by John Carey on p. 50, “Global Warming, faster than expected?”, link here

The main point of the article is that relatively small increases in warming (through increased carbon dioxide levels) can cause runaway train feedback loops.

The most dangerous of these loops could be the melting of polar ice, which can slide off continents into warmer water.  There’s something to the t-shirt phrase “Polar bears are nice.”  Polar melting could contribute to “blocking highs” and extreme, stubborn jet stream dips that bring protracted periods of abnormal weather, such as the mild winter in eastern North America last year and the severe cold in Eastern Europe.  Other loops can caused decreased sunlight reflection with changes in flora, leading to heat in drought in various parts of the world, including uncontrollable and unprecedented wildfires.

Could some sort of feedback loop make super, long tracking tornadoes possible in the Mid Atlantic, or derechoes more common?  Could they make severe late fall hybrid storms like Sandy more frequent? 

The articles discusses warm periods in the Earth's past, tens of millions of years ago, as possibly related to orbital changes.  Likewise, there was once a "snowball Earth". 

There have been statements by some experts that average Earth temperature could rise as much as 8 degrees F by 2100.  From a moral viewpoint, the issue of generativity (having your own skin in a biological future -- children) seems to take on a new life. 
    
Here's something else:  around the Milky Way, it's likely that many planets in the "Goldilocks Zone" for life (with temperatures where water is a liquid) are tidally locked, and have only annular rings with mild climates -- which could have political consequences for the civilizations that are likely to have settled them.  In a couple hundred more years, if we survive long enough and can sustain ourselves, we may know.  

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