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No laughing matter!

Posted 20/04/2010 by RoseS

At the recent spring meeting of the American Chemical Society, air quality expert Frank Mitloehner from the University of California at Davis said that cutting back on the consumption of meat and dairy products will not have a major impact in combating global climate change, despite the repeated claims that link that diets rich in animal products with the production of greenhouse gases. Not only is this scientifically inaccurate, he said, but it also distracts society from embracing effective solutions to climate change. ‘Producing less meat and milk will only mean more hunger in poor countries,’ he added.

While he recoginises that livestock are major producers of methane, this was exaggerated in the 2006 UN report, Livestock’s Long Shadow, which said livestock is responsible for 18% of greenhouse emissions – a higher share than transport. As Mitloehner pointed out, transportation creates an estimated 26% of all greenhouse gas emissions in the US, whereas raising cattle and pigs for food accounts for about 3%.

And now comes research that might let cows and sheep off the hook as a major cause of global climate change, according to recent research conducted at the Karlsruhe Institute of Technology in Germany. The research shows that grazing by cows and sheep can cut the production of nitrous oxide; more often called laughing gas and itself a powerful greenhouse gas. ‘It’s been generally assumed that if you increase livestock numbers you get a rise in emissions of nitrous oxide. This is not the case,’ one of the authors of the research paper, Klaus Butterbach-Bahl told Reuters news agency. The research, published in Nature, says that livestock can help to limit the numbers of microbes, which generate the gas, in the grassland they graze on.

But despite this welcome evidence on greenhouse gas emissions, March 2010 was the warmest on record, according to the US National Oceanic & Atmospheric Administration (NOAA), which has been keeping records since 1880. The NOAA National Climatic Data Centre has reported that the world’s combined global land and ocean surface temperature in March was 13.5oC, some 0.77oC above the average for the 20th century. Taken separately, the worldwide ocean temperature was the highest for any March on record: 0.56oC higher than the average 20th century temperature of 15.9oC, while the global land temperature was 1.36oC above the century average of 5.0oC, the fourth warmest on record.

But while northern Africa, South Asia and Canada were warmer than normal, Mongolia and eastern Russia, northern and western Europe, Mexico, northern Australia, western Alaska and the southeastern US were cooler than normal. El Niño, the periodic event in the tropical Pacific Ocean, weakened to moderate strength in March, following its rapid onset in 2009, however, it did make a considerable contribution to the warmth in the tropical belt and overall ocean temperature, according to NOAA.

Confusing while this might be, there is yet more new information to ‘muddy the waters’ of climate change. Researchers at the US National Center for Atmospheric Research (NCAR) believe that current observational tools cannot account for roughly half of the heat that is believed to have built up on and in the Earth in recent years. The scientists say that satellite sensors, ocean floats and other instruments are inadequate to track this ‘missing’ heat, which may be building up in the deep oceans or elsewhere in the climate system.

The NCAR researchers believe that the contribution of EL Niño, reported by NOAA, may be one way in which this ‘missing’ heat has reappeared.

‘The heat will come back to haunt us sooner or later,’ says NCAR scientist Kevin Trenberth, one of the authors of the article published recently in Science. ‘The reprieve we’ve had from warming temperatures in the last few years will not continue,’ he warns. ‘It is critical to track the build-up of energy in our climate system so we can understand what is happening and predict our future climate.’

So while the cows and sheep have been let off the hook, the oceans are now the villain of the piece. But what about solar storms and flares…….

Neil Eisberg - Editor

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