Ozone: Climate change boosts ultraviolet risk for high latitudes

September 6, 2009,

This undated photo, released by the International Polar Foundation, shows Belgium's Princess Elisabeth base in Antartica. By century's end, UV levels in Antarctica could rise by up to 20 percent at seasonal peaks while average exposure in northern Scandinavia, Siberia and northern Canada could fall by almost a tenth.
(PhysOrg.com) -- Physicists at the University of Toronto have discovered that changes in the Earth's ozone layer due to climate change will reduce the amount of ultraviolet (UV) radiation in northern high latitude regions such as Siberia, Scandinavia and northern Canada. Other regions of the Earth, such as the tropics and Antarctica, will instead face increasing levels of UV radiation.

"Climate change is an established fact, but scientists are only just beginning to understand its regional manifestations," says Michaela Hegglin, a postdoctoral fellow in the Department of Physics, and the lead author of the study published this month in Nature Geoscience.

Using a sophisticated computer model, Hegglin and U of T physicist Theodore Shepherd determined that 21st-century climate change will alter atmospheric circulation, increasing the flux of ozone from the upper to the lower atmosphere and shifting the distribution of ozone within the upper atmosphere. The result will be a change in the amount of UV radiation reaching the Earth's surface which varies dramatically between regions: e.g. up to a 20 per cent increase in UV radiation over southern high latitudes during spring and summer, and a nine per cent decrease in UV radiation over northern high latitudes, by the end of the century.

While the effects of increased UV have been widely studied because of the problem of ozone depletion, decreased UV could have adverse effects too, e.g. on vitamin D production for people in regions with limited sunlight such as the northern high latitudes.

"Both human and ecosystem health are affected by air quality and by UV radiation," says Shepherd. "While there has been much research on the impact of climate change on air quality, our work shows that this research needs to include the effect of changes in stratospheric ozone. And while there has been much research on the impact of ozone depletion on UV radiation and its impacts on human and ecosystem health, the notion that climate change could also affect UV radiation has not previously been considered. This adds to the list of potential impacts of climate change, and is especially important for Canada as northern high latitudes are particularly affected."

Provided by University of Toronto

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2 / 5 (4) Sep 06, 2009
No, the chemicals we have shot up into the atmosphere will be responsible for the loss of Ozone as these chemicals have been up there for a while a take a long time to break down. They damage Ozone until they break down.
1.8 / 5 (5) Sep 06, 2009
"changes in convention?" Someone needs to check their spelling. I think it should be "change in convection".

2 / 5 (4) Sep 08, 2009
Can someone please explain to me how...
A) CFC's a huge, heavy molecule, could kill ozone in the upper atomosphere? That is why we outlawed them. Why aren't there ozone holes over areas where CFC's are released?
B) How can O3 travel upward in the convection currents and sustain itself without degrading to O2?
C) As I understand the process, O3 in the upper atmosphere is actually created there by ionizing radiation.
D) We have no clue what "normal" is for the ozone layer. Since we have little study of it over a short period of time, by the standards involved in climate work.
E) Isn't this simply more hype to support the IPCC and the gorebal warming crowd in support of the carbon trading scam by Congress?
1 / 5 (3) Sep 08, 2009
No, the CFC problem was real. Several ozone holes did begin to form over several large cities in the form of ozone thinning. I remember those days well. You may be too young to remember the days before the ban.

The process for ozone breakdown via CFCs is relatively well known. The problem was not in the existence of the chemicals but in their breakdown in the stratosphere.

They would break down and release free chlorine ions, which would knock an oxygen atom off the ozone, which would re-release the chrorine ions, which would contact more ozone and break it down, etc.

This process still is taking place and will take place until all the CFCs are broken down and the chlorine ions remain bound with something else. Luckily, the action of the CFCs is lessening over time and will do so as long as we continue to prevent their escape into the atmosphere.

Air convection and currents are what spread it around once released into the atmosphere. Another part of the problem was HCFCs as well as CBrCs like Halon, which also was banned.

Most of the ozone thinning forming over the various cities closed up but the chemicals migrated with the air currents to the poles. They assist with the formation of the Antarctic Ozone Hole in combination with normally occurring factors.

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