Archives for September 27, 2007

Nature 449, 382-383 (27 September 2007)

Chemists poke holes in ozone theory

Quirin Schiermeier

Reaction data of crucial chloride compounds called into question.

Extract:

As the world marks 20 years since the introduction of the Montreal Protocol to protect the ozone layer, Nature has learned of experimental data that threaten to shatter established theories of ozone chemistry. If the data are right, scientists will have to rethink their understanding of how ozone holes are formed and how that relates to climate change.

Long-lived chloride compounds from anthropogenic emissions of chlorofluorocarbons (CFCs) are the main cause of worrying seasonal ozone losses in both hemispheres. In 1985, researchers discovered a hole in the ozone layer above the Antarctic, after atmospheric chloride levels built up. The Montreal Protocol, agreed in 1987 and ratified two years later, stopped the production and consumption of most ozone-destroying chemicals. But many will linger on in the atmosphere for decades to come. How and on what timescales they will break down depend on the molecules’ ultraviolet absorption spectrum (the wavelength of light a molecule can absorb), as the energy for the process comes from sunlight. Molecules break down and react at different speeds according to the wavelength available and the temperature, both of which are factored into the protocol.

So Markus Rex, an atmosphere scientist at the Alfred Wegener Institute of Polar and Marine Research in Potsdam, Germany, did a double-take when he saw new data for the break-down rate of a crucial molecule, dichlorine peroxide (Cl2O2). The rate of photolysis (light-activated splitting) of this molecule reported by chemists at NASA’s Jet Propulsion Laboratory in Pasadena, California, was extremely low in the wavelengths available in the stratosphere — almost an order of magnitude lower than the currently accepted rate. “This must have far-reaching consequences,” Rex says. “If the measurements are correct we can basically no longer say we understand how ozone holes come into being.” What effect the results have on projections of the speed or extent of ozone depletion remains unclear.

The abstract of the original paper is here.

CCNet’s take:

CCNet 161/2007 – 27 September 2007 — Audiatur et altera pars

SCIENTIFIC CONSENSUS ON MAN-MADE OZONE HOLE MAY BE COMING APART

As the world marks 20 years since the introduction of the Montreal Protocol to protect the ozone layer, Nature has learned of experimental data that threaten to shatter established theories of ozone chemistry. If the data are right, scientists will have to rethink their understanding of how ozone holes are formed and how that relates to climate change.
–Quirin Schiermeier, News@Nature, 26 September 2007

If the measurements are correct we can basically no longer say we understand how ozone holes come into being.
–Markus Rex, News@Nature, 26 September 2007

Our understanding of chloride chemistry has really been blown apart.
–John Crowley, Max Planck Institute of Chemistry, 26 September 2007

Until recently everything looked like it fitted nicely. Now suddenly it’s like a plank has been pulled out of a bridge.
–Neil Harris, University of Cambridge, 26 September 2007

The new measurements raise “intriguing questions”, but don’t compromise the Montreal Protocol as such, says John Pyle, an atmosphere researcher at the University of Cambridge. “We’re starting to see the benefits of the protocol, but we need to keep the pressure on.” He says that he finds it “extremely hard to believe” that an unknown mechanism accounts for the bulk of observed ozone losses.
–Quirin Schiermeier, News@Nature, 26 September 2007

James Lovelock’s plan to pump ocean water to stop climate change is reported in the UK’s Daily Telegraph today, 27th September.

A plan to save our world from extreme climate change by pumping cold water from the depths of the oceans is outlined today by James Lovelock, the scientist who inspired the greens.

James Lovelock is best known for his ideas that portray Earth as a living thing, a super-organism – named Gaia, after the ancient Earth goddess – in which creatures, rocks, air and water interact in subtle ways to ensure the environment remains stable.

Today Lovelock, of Green College, Oxford University, outlines an emergency way to stimulate the Earth to cure itself with Chris Rapley, former head of the British Antarctic Survey who is now the director of the Science Museum, London.

They believe the answer lies in the oceans, which transport much more heat than the atmosphere and, covering more than 70 per cent of the Earth’s surface.

They propose that vertical pipes some 10 metres across be placed in the ocean, such that wave motion would pump up cool water from 100-200 metres depth to the surface, moving nutrient-rich waters in the depths to mix with the relatively barren warm waters at the ocean surface.

This would fertilise algae in the surface waters and encourage them to bloom, absorbing carbon dioxide greenhouse gas while also releasing a chemical called dimethyl sulphide that is know to seed sunlight reflecting clouds.

Read more.

The article is derived from Lovelock and Rapley’s correspondence in this weeks Nature magazine.

The following article appered in The Sunday Times on 23rd September: The ‘carbon offset’ child labourers, Indians work off West’s holiday guilt.

Extracts:

Pumping furiously on a foot treadle in the afternoon heat, six-year-old Sarju Ram is irrigating her impoverished family’s field, improving the crop and – without knowing it – helping environmentally sensitive holiday-makers assuage their guilt over long-haul flights to dream destinations.

But Sarju and her four brothers and sisters working flat out in a clump of trees that provide scant shelter from the sun illustrate a growing argument over claims that British environmentalists’ efforts to curb greenhouse emissions are inadvertently fuelling an increase in child labour.

Sarju’s family is a beneficiary of Climate Care, an organisation that helps some of Britain’s leading public figures and companies to offset their carbon dioxide emissions by funding sustainable energy projects.

Customers of British Airways are among those who have been encouraged to log on to Climate Care’s website and calculate how many tonnes of greenhouse gases their flights will generate, and how much it will cost to neutralise the impact on the atmosphere. A flight to Barbados for a family of four, for example, generates 7.55 tonnes of carbon dioxide, which will cost them £56.64 to offset.

Climate Care uses the money to help persuade families such as Sarju’s to give up labour-saving diesel pumps and buy human-powered treadles instead. It claims that by using the treadle, a family will save money on diesel and hire charges, earn more from increased crops and cut the carbon emissions that would have been produced by the pump.

Last week Indian experts criticised the scheme, saying it was promoting child labour and forcing poor farmers to work harder so that wealthy air travellers could enjoy exotic holidays without worrying about the environment.

“The problem is the number of times child labour is involved,” claimed Ashutosh Pandey of Emergent Ventures India, which advises companies on clean technology.

“It’s not being monitored properly. It’s not reducing emissions. People are selling their diesel pumps to others who are using them.”

Michael Buick, a spokesman for the Oxford-based Climate Care, confirmed that children were working the pumps it promotes, but said that people had to focus on the benefits to the whole family.

He said his group was proud of its scheme, which had led to more than half a million foot treadles being sold, and had won several awards. Four reports had identified major benefits.

According to Buick, critics are mistaken in claiming that diesel pumps are better than human-powered alternatives, because they are costly to run. The treadles meant farmers could rely on increased crops.

Buick said that by “all mucking in” families were able to increase yields and earn more to pay for children to go to school. The extra income also meant fathers could stay with their families rather than leaving them to look for work in the cities.

“If mum is planting and harvesting, the daughters help out. It’s just a different way of life. The phrase ‘child labour’ is emotive. It implies factories, but these are family farms where everyone gets stuck in, watering the crops and taking a turn on the treadle pump,” he said.