Sunday, November 23, 2008

Models Schmodels... Things are Heating Up!

I enjoy the global warming debate. Back shortly after I bought my house in an area inches above sea level I was surprised to learn that the IPCC was predicting sea level rises of several feet before the end of the 20th century. That of course worried me. I don't mind a bath in a bathtub but when the whole house would be a bathtub 24x7, that is disconcerting. So I've been a keen observer of global warming ever sense.

Add to this my experience with computer modeling and the ease with which you can miscalculate something base on your assumptions, I've been leery of model predictions ever since.

Here is yet another example of how the ever receeding horrors of global warming need to be modified as scientists find that their models need "adjusting" as they encounter the difficulties of realistically representing the carbon cycle. Here is another example where tweaking means that the apocalypse of heat death is moved out yet again for a few more years...

From a news report on PhysOrg.com:

A new Cornell study, published online in Nature Geosciences, quantified the amount of black carbon in Australian soils and found that there was far more than expected, said Johannes Lehmann, the paper's lead author and a Cornell professor of biogeochemistry. The survey was the largest of black carbon ever published.

As a result of global warming, soils are expected to release more carbon dioxide, the major greenhouse gas, into the atmosphere, which, in turn, creates more warming. Climate models try to incorporate these increases of carbon dioxide from soils as the planet warms, but results vary greatly when realistic estimates of black carbon in soils are included in the predictions, the study found.

...

By entering realistic estimates of stocks of black carbon in soil from two Australian savannas into a computer model that calculates carbon dioxide release from soil, the researchers found that carbon dioxide emissions from soils were reduced by about 20 percent over 100 years, as compared with simulations that did not take black carbon's long shelf life into account.

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