View Full Version : Ozone effect on Icehouse (East Antarctica) - good or bad?
zankaon
Sep20-09, 01:27 AM
Removing ozone from lower stratosphere (i.e. ozone hole) cools cold air further over Antarctica. Also ozone decrease, and carbon dioxide increase both contribute to increase in southern westerlies, which support ACC (Antarctica circumpolar current). Increase in westerlies pushes surface cold water away from Antarctica, and allows upwelling of salty warm water. Do we fully understand what effect ozone (increase or decrease) might have on Antarctica weather? [URL="http://www.nature.com/nature/journal/v451/n7176/full/nature06590.html"] Should we go slow in any intervention?
J. R. Toggweiler & Joellen Russell, Ocean circulation in a warming climate, Nature 451, 286-288 17 January 2008, and references therein.
http://en.wikipedia.org/wiki/Antarctica#Ozone_depletion
It doesn't make a lot of sense that Ozone decreases and Carbon Dioxide increases would both contribute to increased southern westerlies. Ozone and Carbon Dioxide are both greenhouse gases, so it would be more logical if their respective decreases and increases would tend to cancel each other out. However, Ozone is seasonal so that may be a complicating factor.
Anyhow, last years ozone hole was the largest ever which probably happened because air pollution of ozone depleting chemicals are near record high levels despite all the good intentions of many people. Good news is that this years hole appears to be somewhat smaller...
GENEVA – The World Meteorological Organisation said Wednesday that the ozone hole is expected to be smaller in 2009 than a year ago.
"The meteorological conditions observed so far could indicate that the 2009 ozone hole will be smaller than those of 2006 and 2008 and close to that of 2007," said the UN agency in a statement.
http://www.vancouversun.com/technology/Ozone+hole+smaller+2009+than+2008/2000232/story.html
Skyhunter
Sep21-09, 02:25 PM
Ozone also absorbs ultraviolet in the stratosphere, that is the primary reason there is a tropopause. It is primarily chlorine radicals from the destruction of CFCs that accumulate on polar stratospheric clouds at temperatures below -70C. These radicals react with sunlight and ozone when spring returns to Antarctica. As your link states, it is primarily weather conditions that drive the size of the hole. Especially when stratospheric temperatures are below -70C for extended periods with numerous PSCs forming.
Nitrous oxide has replaced CFCs as the primary ozone depleting chemical overall, but CFCs are still dominant in the Antarctic.
http://www.sciencemag.org/cgi/rapidpdf/1176985v2.pdf?ijkey=gkBXN.9.4TA2E&keytype=ref&siteid=sci
CO2 forcing is overwhelmed in the Antarctic by ozone depletion. The Antarctic is colder than the Arctic because of the glaciers on the continent. Unlike The Arctic where the sea ice melts and lowers albedo, Antarctica remains covered by snow and ice year around. When the ozone hole recovers Antarctica will warm faster than it is at present.
I can understand that cooling due to ozone depletion could overwhelm warming due to CO2 increases. However, Antarctica is at much higher average elevation than the Arctic which makes it much cooler. In addition, it's much drier (most of it is a desert), so that also drives temperatures down.
The lack of humidity means that it could also warm very quickly (since water vapor is such a strong greenhouse gas).
mgb_phys
Sep21-09, 06:31 PM
It doesn't make a lot of sense that Ozone decreases and Carbon Dioxide increases would both contribute to increased southern westerlies. Ozone and Carbon Dioxide are both greenhouse gases,
Energy absorbed by ground level CO2 and heating the lower troposphere could have an opposite effect to energy absorbed by a thin layer of O3 in the upper stratosphere reducing the amount of the same wavelnegths reaching the ground
zankaon
Sep22-09, 02:28 AM
Removing ozone from lower stratosphere (i.e. ozone hole) cools cold air further over Antarctica. Also ozone decrease, and carbon dioxide increase both contribute to increase in southern westerlies, which support ACC (Antarctica circumpolar current). Increase in westerlies pushes surface cold water away from Antarctica, and allows upwelling of salty warm water. Do we fully understand what effect ozone (increase or decrease) might have on Antarctica weather? [URL="http://www.nature.com/nature/journal/v451/n7176/full/nature06590.html"] Should we go slow in any intervention?
J. R. Toggweiler & Joellen Russell, Ocean circulation in a warming climate, Nature 451, 286-288 17 January 2008, and references therein.
http://en.wikipedia.org/wiki/Antarctica#Ozone_depletion
Thermodynamics, gravity, and the Icehouse
Heat flows from hot to cold. Water flows downhill. Nature's inclinations seem clear. Leaning against such inclinations, might gradual warming of East Antarctica seem possible and desirable? Can the fridgerator door be kept slightly open? Might West Antarctica be an example of the latter?
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