[getsmart-l] What's happening to the ozonehole? It might affect warming in the southern hemisphere

Gloria Boxen gboxen at rogers.com
Wed Aug 18 15:28:30 EDT 2010


My question:

If the ozone hole is closing why have our uv radiation readings gone up every 
summer?  It seems to me that the scale has increased for the last 3 summers as 
the highs are higher and that the sunlight levels at 5:00 pm in July were higher 
than I remember previously- that they resembled those of a midsummer afternoon.

http://www.eoearth.org/article/Factors_affecting_surface_ultraviolet_radiation_levels_in_the_Arctic



http://www.sciencedaily.com/releases/2010/01/100125192016.htm


Web address:
     http://www.sciencedaily.com/releases/2010/01/
     100125192016.htm  
Ozone Hole Healing Could Cause Further Climate Warming
enlarge

Total Antarctic ozone - September 2009. (Credit: NOAA)
ScienceDaily (Jan. 26, 2010) — The hole in the ozone layer is now steadily 
closing, but its repair  could actually increase warming in the southern 
hemisphere, according to  scientists at the University of Leeds.

The Antarctic ozone hole was once regarded as one of the biggest  environmental 
threats, but the discovery of a previously undiscovered  feedback shows that it 
has instead helped to shield this region from  carbon-induced warming over the 
past two decades.

High-speed winds in the area beneath the hole have led to the  formation of 
brighter summertime clouds, which reflect more of the sun's  powerful rays.

"These clouds have acted like a mirror to the sun's rays, reflecting  the sun's 
heat away from the surface to the extent that warming from  rising carbon 
emissions has effectively been cancelled out in this  region during the 
summertime," said Professor Ken Carslaw of the  University of Leeds who 
co-authored the research.

"If, as seems likely, these winds die down, rising CO2 emissions could then 
cause the warming of the southern hemisphere to  accelerate, which would have an 
impact on future climate predictions,"  he added.
The key to this newly-discovered feedback is aerosol -- tiny  reflective 
particles suspended within the air that are known by experts  to have a huge 
impact on climate.

Greenhouses gases absorb infrared radiation from the Earth and  release it back 
into the atmosphere as heat, causing the planet to warm  up over time. Aerosol 
works against this by reflecting heat from the sun  back into space, cooling the 
planet as it does so.

Beneath the Antarctic ozone hole, high-speed winds whip up large  amounts of sea 
spray, which contains millions of tiny salt particles.  This spray then forms 
droplets and eventually clouds, and the increased  spray over the last two 
decades has made these clouds brighter and more  reflective.

As the ozone layer recovers it is believed that this feedback  mechanism could 
decline in effectiveness, or even be reversed, leading  to accelerated warming 
in the southern hemisphere.

"Our research highlights the value of today's state-of- the-art  models and 
long-term datasets that enable such unexpected and complex  climate feedbacks to 
be detected and accounted for in our future  predictions," added Professor 
Carslaw.

The Leeds team made their prediction using a state-of-the-art global  model of 
aerosols and two decades of meteorological data. The research  was funded by the 
Natural Environment Research Council's Surface  Ocean-Lower Atmosphere Study (UK 
SOLAS) and the Academy of Finland  Centre of Excellence Programme.

Email or share this story:
    | More 
________________________________
 
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) 
from materials provided by University of Leeds, via EurekAlert!, a service of 
AAAS.
________________________________
 
Journal Reference:
	1. . Aerosol climate feedback due to decadal increases in southern hemisphere 
wind speeds. Geophysical Research Letters, 2010; (in press)
Need to cite this story in your essay, paper, or report? Use one of the 
following formats: 

 APA

 MLA 
University of Leeds (2010, January 26). Ozone hole healing could cause further 
climate warming. ScienceDaily. Retrieved August 17, 2010, from 
http://www.sciencedaily.com­/releases/2010/01/100125192016.htm 

Note: If no author is given, the source is cited instead.




http://news.nationalgeographic.com/news/2010/05/100505-science-environment-ozone-hole-25-years/


Brian Handwerk
for National Geographic News
Published May 5, 2010
Background information is given 




...Ozone Recovery to Warm Antarctica?
Meanwhile, some scientists say the environmental triumph of a recovering ozone 
layer could have a troubling side effect: boosting global warming, at least in 
the Antarctic region.

Ozone  itself is a greenhouse gas. A thinner ozone layer not only reduced heat  
trapped over the region, it helped stir circumpolar winds, which in  turn 
created sea spray that formed reflective, cooling clouds.

"It's  very difficult to quantify the impact on a global scale, but I think  the 
evidence suggests filling the hole will have a regional effect on  the 
Antarctic, possibly leading to more warming for the bulk of the  Antarctic," 
Shanklin said. "That could drastically change predictions  about global sea 
level change." 



Ken Carslaw of the U.K.'s University of Leeds was a co-author on the study that  
suggested closing the ozone hole would lead to a bump in Antarctic  warming. 
Still, he thinks that any warming mitigation produced by the  ozone hole was 
merely a side effect and not a net gain.

"I wouldn't say that these discoveries [of possible warming] suggest the 
formation of the ozone hole was a good thing," he said.

NASA's Newman agreed: "The consequences of unabated CFC growth were disastrous 
for life," he said.

"So  at some point you had to act, and fortunately they acted before it  became 
a really severe problem. We never got to the level of an  environmental 
catastrophe.

"It really is a testament to the good  science that went into [understanding] 
the ozone hole and the nerve of  the politicians to act on that science."
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.web.net/archives/getsmart-l/attachments/20100818/b432728a/attachment.htm>


More information about the getsmart-l mailing list