Feeds

Ozone layer hits new depletion record

Blame the weather

The next step in data security

Despite optimism earlier this year that the ozone hole was stabilising and might even have begun to repair itself, scientists at the European Space Agency report that 2006 saw record losses of ozone over the south pole.

Data from ESA's Envisat satellite show that although the area of the ozone hole (this year, 28m square kilometres) is not quite as large as it was in 2000, some 40 million tonnes of ozone were lost during the southern hemisphere winter. This is one million tonnes greater than the previous record from 2000.

The loss is calculated by combining the area of the hole with the depth of the ozone layer. The depth is measured in Dobson units, which describes the thickness of the layer directly over the location being measured, ESA explains.

This year saw the ozone approach the thinnest it has ever been, around 100 dobson units, approaching the record of 1998.

So although it is not as large as the hole in 2000, nor quite as thin as the layer in 1998, the two combined mean the layer has been depleted this year more than ever before.

ESA's atmospheric engineer Claus Zehner explains that the conditions over the Southern pole this year were ideal for depleting the ozone layer:

"Such significant ozone loss requires very low temperatures in the stratosphere combined with sunlight. This year’s extreme loss of ozone can be explained by the temperatures above Antarctica reaching the lowest recorded in the area since 1979," he said.

The Ozone layer, to fill in an unlikely gap in your knowledge, is a protective layer of the atmosphere which absorbs much of the harmful UV from the sun's rays. Its composition naturally fluctuates during the year. It is typically thicker in summer, and thinner in the winter.

The conditions for the hole are set up during the Antarctic winter. In this cold season, a weather pattern known as the polar vortex keeps the atmospheric mass above the Antarctic continent isolated from exchanges with warmer mid-latitude air.

This keeps the air mass above the continent cold, and in the cold and dark, clouds that contain chlorine can form in the polar stratosphere.

Once the spring returns, this chlorine, much of it originating from man-made pollutants like chlorofluorocarbons, disrupts the ozone layer causing the hole with which we are all now so familiar.

Zehner says the current consensus is that the ozone layer will recover from its human induced damage by 2060. Long term measurements, he argues, are key to understanding this process. ®

New hybrid storage solutions

More from The Register

next story
PORTAL TO ELSEWHERE scried in small galaxy far, far away
Supermassive black hole dominates titchy star formation
Bacon-related medical breakthrough wins Ig Nobel prize
Is there ANYTHING cured pork can't do?
Boffins say they've got Lithium batteries the wrong way around
Surprises at the nano-scale mean our ideas about how they charge could be all wrong
Edge Research Lab to tackle chilly LOHAN's final test flight
Our US allies to probe potential Vulture 2 servo freeze
Europe prepares to INVADE comet: Rosetta landing site chosen
No word yet on whether backup site is labelled 'K'
Stray positrons caught on ISS hint at DARK MATTER source
Landlubber scope-gazers squint to horizons and see anti-electron count surge
Cracked it - Vulture 2 power podule fires servos for 4 HOURS
Pixhawk avionics juice issue sorted, onwards to Spaceport America
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.