Thursday, April 13, 2017

A Critical Tipping Point Awaits Us

For millions of years out atmosphere has had just enough CO2 to permit life on this planet to prosper. Without CO2 our atmospheric temperature our planet would be a snowball.  With CO2 we have a global temperature that has brought us the bounty of life that has existed over eons.

But too much of it can be a problem as well.  I have posted about this, here and here.

How much danger are we in?  The consequences of the CO2 we are pouring into the atmosphere are dire indeed.  But we may have more to worry about than just what human activity is causing.  There are large reservoirs of CO2 and methane held in soil and in the sea.  But these reservoirs of greenhouse gases are in great danger of being released.
As global warming thaws the permafrost, the frozen land that covers nearly six million square miles of the earth, a big question for scientists is: How much will be lost?
The answer, according to a new analysis: more than many of them thought. 
A study published Tuesday in the journal Nature Climate Change suggests that as the planet warms toward two degrees Celsius (3.6 degrees Fahrenheit) above preindustrial levels, each degree Celsius of warming will lead to the thawing of about 1.5 million square miles of permafrost.
 We could pass a critical tipping point.
Global warming will defrost much more permafrost than we thought, a new study finds. Every 1°C (1.8°F) of additional warming would thaw one-quarter of the earth’s frozen tundra area — releasing staggering amounts of heat-trapping greenhouse gases (GHGs).
Those GHGs would in turn warm the planet more, melting more permafrost, releasing more GHGs, and so on. This is perhaps the most dangerous amplifying carbon-cycle feedback humanity faces — considering permafrost contains twice as much carbon as the atmosphere does today.
If we pass this tipping point, we could experience the direst of consequences, the end of civilization itself.  We must not delay.  We must stop pouring CO2 into the atmosphere now, not the next decade, not even next year.