Book of the Month

Carbon Emissions May Prevent New Ice Age-BBC

by NCD 1/9/2012 - 3:25 pm

....Using analysis of orbital data as well as samples from rock cores drilled in the ocean floor, Dr Skinner's team identified an episode called Marine Isotope Stage 19c (or MIS19c), dating from about 780,000 years ago, as the one most closely resembling the present.

The transition to the Ice Age was signaled, they believe, by a period when cooling and warming seesawed between the northern and southern hemispheres, triggered by disruptions to the global circulation of ocean currents.

If the analogy to MIS19c holds up, this transition ought to begin within 1,500 years, the researchers say, if CO2 concentrations were at "natural" levels.....

Every cloud of noxious gas has at least a little silver lining!

Read the full article at http://www.bbc.co.uk/news/science-environment-16439807

Interesting article. I think most people intuitively assumed global warming would delay the return of glacial conditions, but here's research backing them up.

It annoys me, however, that "environmental reporters" (like this one) can write as if there were a "last ice age," then the current interglacial period, and maybe, down the road, a "next ice age."

We're in an ice age now. See Antarctica. See Greenland. See the Himalayas. See high mountains world-wide. Permanent glaciers. The past 15,000 years or so, during which all that we call civilization emerged, is an anomaly. More normal is perhaps 100,000 years of two-mile-thick glaciers covering the sites of London and New York. Stack a few dozen alternations of glacial and interglacial, and you get the current ice age, which has endured millions of years.

I don't doubt the recent surge in CO2 will slow the cycle of hot and cold. But weighed against the orbital cycles that have governed Earth's rollercoaster climate up till now, it's just a drop in the bucket. It won't be in our lifetimes, but the ice is going to return. 

by acanuck 1/9/2012 - 9:17 pm

This is what I think of when some people say that they don't think that human contributions are responsible for the majority of global warming (a fall back position after saying there is no global warming). They'll say, oh, maybe 10-20% or some other made up number. Well, my made up number is 120-150% of global warming is due to human factors, because without it we'd likely be sinking into the next glacial period.

Temperature, CO2, and dust cycles

(These charts go from recent on the left, to 400,000 years ago on the far right, but they're missing the very recent. You'll note that the top of the chart for carbon dioxide stops at 300, but we're currently at 390 ppmv CO2. Look at that chart again and let that sink in.)

by Verified Atheist 1/13/2012 - 10:02 am

It's curious that dust concentration peaks roughly when CO2 and temperature both hit their low points, Atheist. Do you have an explanation to offer? Fiercer winds because of temperature differences between glaciated and ice-free areas? But you'd think the more of Earth's surface is covered by ice, the less dust is exposed to being whipped into the atmosphere. Hmmm.

by acanuck 1/13/2012 - 9:19 pm (re: Verified Atheist)

I found that interesting as well, and have no good explanation. Of course, even during the coldest times, I think the majority of the land mass was still ice-free, so maybe there were worldwide analogues of the Dust Bowl?

by Verified Atheist 1/15/2012 - 11:10 am (re: acanuck)

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