Unprecedented Arctic ozone hole in 2011

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Posted by: JeffMasters, 2:01 PM GMT on October 04, 2011

An unprecedented ozone hole opened in the Arctic during 2011, researchers reported this week in the journal Nature. Holes in the Antarctic ozone layer have opened up each spring since the early 1980s, but the Arctic had only shown modest springtime ozone losses in the 5% - 30% range over the past twenty years. But this year, massive ozone destruction of 80% occurred at altitudes of 18 - 20 kilometers in the Arctic during spring, resulting in Earth's first known case of twin ozone holes, one over each pole. During late March and portions of April, the Arctic ozone hole was positioned over heavily populated areas of Western Europe, allowing large levels of damaging ultraviolet rays to reach the surface. UV-B radiation causes skin damage that can lead to cancer, and has been observed to reduce crop yields in two-thirds of 300 important plant varieties studied (WMO, 2002.) The total loss of ozone in a column from the surface to the top of the atmosphere reached 40% during the peak of this year's Arctic ozone hole. Since each 1% drop in ozone levels results in about 1% more UV-B reaching Earth's surface (WMO, 2002), UV-B levels reaching the surface likely increased by 40% at the height of this year's hole. We know that an 11% increase in UV-B light can cause a 24% decrease in winter wheat yield (Zheng et al., 2003), so this year's Arctic ozone hole may have caused noticeable reductions in Europe's winter wheat crop.

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Greenhouse gases have also led to the cooling of the atmosphere at levels higher than the stratosphere. Over the past 30 years, the Earth's surface temperature has increased 0.2 - 0.4 °C, while the temperature in the mesosphere, about 50 - 80 km above ground, has cooled 5 - 10 °C (Beig et al., 2006). There is no appreciable cooling due to ozone destruction at these altitudes, so nearly all of this dramatic cooling is due to the addition of greenhouse gases to the atmosphere. Even greater cooling of 17 °C per decade has been observed high in the ionosphere, at 350 km altitude. This has affected the orbits of orbiting satellites, due to decreased drag, since the upper atmosphere has shrunk and moved closer to the surface (Lastovicka et al., 2006). The density of the air has declined 2 - 3% per decade the past 30 years at 350 km altitude. So, in a sense, the sky IS falling due to the greenhouse effect!

Since any increase in solar energy would heat both the lower and upper atmosphere, the observed drop in upper atmospheric temperatures in the past 30 years argues against an increase in energy coming from the sun being responsible for global warming. The observed cooling of the upper atmosphere is strong evidence that the warming at Earth's surface is due to human-emitted greenhouse gases that trap heat near the surface and cause compensating cooling aloft. It should also give us additional confidence in the climate models, since they predicted that this upper atmospheric cooling would occur. Keep in mind, also, that 2010 was tied for Earth's hottest year on record, and the amount of energy coming from the sun during 2009 - 2010 was the lowest since satellite measurements began in the late 1970s. There has been no long-term increase in energy coming from the sun in recent decades, and the notion that global warming is due to an increase in energy coming from the sun simply doesn't add up.

The development of an ozone hole in the Arctic is a discouraging reminder that humans are capable of causing harmful and unexpected planetary-scale changes to the environment. A 2002 assessment of the ozone layer by the World Meteorological Organization concluded that an Arctic ozone hole would be unlikely to occur, due to the lack of a strong Arctic vortex in winter, and the fact CFCs levels had started to decline. However, an Arctic ozone hole may now become a regular visitor in the future.

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It is highly probable that we will see future nasty climate change surprises far more serious than the Arctic ozone hole if we continue on our present business-as-usual approach of emitting huge quantities of greenhouse gases. Humans would be wise to act forcefully to cut emissions of greenhouse gases, as the cost of inaction is highly likely to be far greater than the cost of action.


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