Hello Earth Science!

Peter DeMenocal mentioned in Monday’s lecture that the last ten years have been a plateau of sorts in global temperature. How serious is this problem for proponents of global warming?

NY Times: What makes a trend?

Science Magazine: A Cold Spell

Another thing mentioned in the lecture: there are three broad factors that impact the global temperature.

a) The energy input from the sun (energy in ultimately must equal energy out, some of the energy out comes from thermal radiation)

b) Reflectivity, or albedo (this directly reflects light received by the sun–the Earth does not absorb this light and so, is not warmed by it).

c) Greenhouse effect (certain gasses have a tendency to trap light of different wavelengths so that they heat the planet up more. These gasses act like a blanket. The most famous is CO2, over which we humans have a pretty strong influence. The most effective such gas however is H2O, and it is predominantly responsible for keeping our planet temperate enough for life–otherwise it would be much too cold for us).

One idea to help mitigate climate change is to seed more cloud cover using dust particles. The science behind this is still quite primitive however. A recent study may be of interest:

EurekAlert: Dust and Climate Change

A common argument against action to mitigate climate change is that it will wreck the economy. A number of articles have recently come out arguing against this. For example:

WSJ: Not As Costly As We Think

I think another important point along these lines is that the longer we wait the greater the costs of changing course–this is true for many reasons: positive feedbacks will be stronger and thus require a more disproportionate response on our end; in order to achieve safe targets (like 350 ppm of Carbon in the atmosphere) we will have to do more in a shorter time which will involve more drastic economic and social measures; there will be a gradual increase in the severity of the climate impact on many regions in the world, taking an increasing economic (not to mention) human toll.

Finally, modeling the climate is very difficult as it is an extraordinarily complex system. A recent New York Times article looked at one area in applied mathematics that may someday be brought to bear on this:

NY Times: Lagrangean Coherent Structures


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