Hi combjelly; Re: "Might it [next ice age] happen in the far future? Sure. But we are talking 100s of thousands of years. The consequences of climate change are much closer in time and almost as severe."
What we're in now is called an "interglacial". It's been going on for about 11,400 years. At the end of each interglacial, an ice age begins.
As long as we keep the CO2 levels high, current thinking is that we'll avoid the next ice age. Here's a recent paper at a peer reviewed journal that reads directly on this issue:
No glacial inception is projected to occur at the current atmospheric CO2 concentrations of 390 ppmv (ref. 1).
...
Assuming that ice growth mainly responds to insolation and CO2 forcing, this analogy suggests that the end of the current interglacial would occur within the next 1500 years, if atmospheric CO2 concentrations did not exceed 2405 ppmv.
Determining the natural length of the current interglacial
Tzedakis, Channell, Hodell, Kleiven and Skinner
Nature Geoscience Letters, January 8, 2012
deas.harvard.edu
In other words, if it weren't for our keeping CO2 in the atmosphere, the next ice age would start around 1500 years from now, *not* as you wrote: "100s of thousands of years".
As to global warming being "almost as severe" as an ice-age, this is silly. During an ice age Canada and the northern part of the US are covered with ice all year round. Over the last 3000 years, periods when the global climate was cooler are associated with famines. The reason is simple. Warming increases the growing season. Warming also changes which crops can survive the summer's hottest temperatures but that's a matter of crop selection. For example, Iowa farmers who planted sorghum instead of corn got nice crops during last year's hot summer.
cbsnews.com
-- Carl
P.S. Your recent replies indicate that you don't read the links I give you, but if anyone else is interested, here is some reading on the subject:
"In the present interglacial, the Holocene, the climatic optimum occurred during the Subboreal (5 to 2.5 ka BP, which corresponds to 3000 BC-500 BC) and Atlanticum (9 to 5 ka, which corresponds to roughly 7000 BC-3000 BC). Our current climatic phase following this climatic optimum is still within the same interglacial (the Holocene). This warm period was followed by a gradual decline until about 2,000 years ago, with another warm period until the Little Ice Age (1250-1850)."
en.wikipedia.org
cropwatch.unl.edu |
