With global warming, the weather is just the same, only more so
May 31st 2011
I was pleased when I found a plug-in for my blog that gave the average levels of CO2 in the atmosphere. I regard climate change to be the greatest threat humanity faces over the next century, and the levels attained, according to the display, were terrifying. 393.18 parts per million.
There was just one problem: it was wrong. It was out of date, and badly so.
The US government’s Earth Systems Research Laboratory at Mauna Loa in Hawaii, came out with a report this week that CO2 peaked last week at 394.97ppm. That set a new record for greatest concentrations of CO2.
To give the numbers some perspective, the ice core samples show that for most of the last millennium, CO2 levels stayed within a couple of points of 282ppm. That was high by Holocene standards. Over the previous 450,000 years, it usually ranged between 290ppm and 190ppm, in a cycle running between 100,000 and 125,000 years. Big, dramatic falls were known to occur over the period of 10,000 years, usually triggering an ice age. Over the past 450,000 years, the highest level recorded prior to the past hundred years was 314ppm, some 4,700 years ago. That may have played a significant role in humanity migrating out beyond the tropics. Continue reading “Weather or Not”
