Pollution Controls Cause Polar Ice Cap Melting

Remember how Polar bears are drowning because the ice caps are melting? Remember how the ice caps are melting because of CO2 emissions? Well new research at NASA suggests that the ice caps may be melting not because of CO2, but because of the elimination of aerosol particle emissions. In other words, pollution controls put into place in the 70's could be the cause of the polar ice caps melting.

New research from NASA suggests that the Arctic warming trend seen in recent decades has indeed resulted from human activities: but not, as is widely assumed at present, those leading to carbon dioxide emissions. Rather, Arctic warming has been caused in large part by laws introduced to improve air quality and fight acid rain.

Dr Drew Shindell of NASA’s Goddard Institute of Space Studies has led a new study which indicates that much of the general upward trend in temperatures since the 1970s - particularly in the Arctic - may have resulted from changes in levels of solid “aerosol” particles in the atmosphere, rather than elevated CO2. Arctic temperatures are of particular concern to those worried about the effects of global warming, as a melting of the ice cap could lead to disastrous rises in sea level - of a sort which might burst the Thames Barrier and flood London, for instance.

Shindell’s research indicates that, ironically, much of the rise in polar temperature seen over the last few decades may have resulted from US and European restrictions on sulphur emissions. According to NASA:

Sulfates, which come primarily from the burning of coal and oil, scatter incoming solar radiation and have a net cooling effect on climate. Over the past three decades, the United States and European countries have passed a series of laws that have reduced sulfate emissions by 50 percent. While improving air quality and aiding public health, the result has been less atmospheric cooling from sulfates.

On NASA’s site, Shindell continues:

In the modeling experiment, Shindell and colleagues compiled detailed, quantitative information about the relative roles of various components of the climate system, such as solar variations, volcanic events, and changes in greenhouse gas levels. They then ran through various scenarios of how temperatures would change as the levels of ozone and aerosols — including sulfates and black carbon — varied in different regions of the world. Finally, they teased out the amount of warming that could be attributed to different climate variables. Aerosols loomed large.

The regions of Earth that showed the strongest responses to aerosols in the model are the same regions that have witnessed the greatest real-world temperature increases since 1976. The Arctic region has seen its surface air temperatures increase by 1.5 C (2.7 F) since the mid-1970s. In the Antarctic, where aerosols play less of a role, the surface air temperature has increased about 0.35 C (0.6 F).

That makes sense, Shindell explained, because of the Arctic’s proximity to North America and Europe. The two highly industrialized regions have produced most of the world’s aerosol emissions over the last century, and some of those aerosols drift northward and collect in the Arctic. Precipitation, which normally flushes aerosols out of the atmosphere, is minimal there, so the particles remain in the air longer and have a stronger impact than in other parts of the world.


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