Sunday, February 28, 2010

Local effects of global warming investigated

If you looked at the blogs and articles by deniers of anthropogenic global warming (AGW), it would appear that flaw after flaw has been demonstrated in the science and data behind our understanding of AGW, yet in the real world, this is not the case, and the scientists keep on working on expanding their, and our, understanding of the effects of AGW.

Generally, the effects have been considered on a global scale (the Earth as a whole), or very localized scale (e.g. individual glaciers), but our understanding of how certain types of climate will change have been somewhat lacking. It has been assumed that a climate belt would change more or less uniformly, but nobody has known for sure.

Now, we are a bit closing in knowing, and it appears that climate belts won't change uniformly.

ScienceDaily reports on a new study, which looks into this very subject: Tropics: Global Warming Likely to Significantly Affect Rainfall Patterns

Climate models project that the global average temperature will rise about 1°C by the middle of the century, if we continue with business as usual and emit greenhouse gases as we have been. The global average, though, does not tell us anything about what will happen to regional climates, for example rainfall in the western United States or in paradisical islands like Hawai'i.

Analyzing global model warming projections in models used by the Intergovernmental Panel on Climate Change, a team of scientists headed by meteorologist Shang-Ping Xie at the University of Hawaii at Mānoa's International Pacific Research Center, finds that ocean temperature patterns in the tropics and subtropics will change in ways that will lead to significant changes in rainfall patterns. The study will be published in the Journal of Climate this month, breaking ground on such regional climate forecasts.

Scientists have mostly assumed that the surfaces of Earth's oceans will warm rather evenly in the tropics. This assumption has led to "wetter-gets-wetter" and "drier-gets-drier" regional rainfall projections. Xie's team has gathered evidence that, although ocean surface temperatures can be expected to increase mostly everywhere by the middle of the century, the increase may differ by up to 1.5°C depending upon the region.

"Compared to the mean projected rise of 1°C, such differences are fairly large and can have a pronounced impact on tropical and subtropical climate by altering atmospheric heating patterns and therefore rainfall," explains Xie. "Our results broadly indicate that regions of peak sea surface temperature will get wetter, and those relatively cool will get drier."

So, not only will the climate get warmer, but the rainfall patterns are likely to change as well. This is pretty bad news, though not really that surprising, when one stops and think about it - the only reason why people have assumed otherwise, is because of lack of data and models. Now we have the data and models, and can make more precise predictions.

It doesn't look like the mentioned article has been published yet, though I could have overlooked it - Shang-Ping Xie has published quite a few articles on subjects related to climate.

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Anonymous what are the effects of global warming said...

The climate is getting warmer, you must be a fool to deny it. We were given this gift called earth, and we just about destroyed it. But people prefer to call those who talk about it "bleeding hearts"and "tree huggers". What a shame.

April 09, 2011 2:42 PM  

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