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New Data Clearly Links Storms and Warming
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New Data Clearly Links Storms and Warming
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by Stephen Leahy
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BROOKLIN, Canada - Canada's leading scientific society on climate called for urgent government action on climate change at its most recent national conference last week.
Stronger and more frequent hurricanes in summer and stronger winter storms are clearly the result of climate change, according to new scientific studies reported at the 40th annual Canadian Meteorological and Oceanographic Society (CMOS) congress in Toronto.
"Climate change is real, the Kyoto Protocol is an important first step, but we need to do a lot more," Ian Rutherford, CMOS executive-director, told IPS.
"(T)he scientific evidence dictates that in order to stabilise the climate, global reductions in greenhouse gas emissions need to go far beyond those mandated under this Kyoto Protocol," said a statement endorsed by the CMOS membership representing more than 800 public and private scientists.
Although not the first time the Society has made public statements, it has been quite vocal about climate change of late. Part of the reason is that Canada's new Conservative government does not support the Kyoto Protocol for lower emissions of greenhouse gases, and opposed stricter emissions for a post-Kyoto agreement at a United Nations meeting in Bonn in May.
Another reason is that a small, previously invisible group of global warming sceptics called the Friends of Science are suddenly receiving attention from the Canadian government and media.
"The Conservative government is listening to them (the sceptics) because they tell them what they want to hear," he said.
No member from Friends of Science presented any papers, viewpoints or even attended the CMOS meeting, Rutherford noted. "They never present their arguments in front of scientists and should not be listened to," he said.
Those sceptics probably would not have enjoyed listening to the first physical evidence linking global warming to increased hurricane activity and intensity presented at the congress.
Using sea surface temperatures of the tropical Atlantic Ocean over many decades, Robert Scott, an oceanographer at the University of Texas, showed that the area that spawns hurricanes has grown dramatically in recent years.
Scott's data shows that since 1970, the eastern side of the Atlantic, near the coast of Africa, has become warmer, topping the 26.5 C. temperature threshold for hurricanes to form. That means that the traditional area where hurricanes get their start has expanded by hundreds of kilometres.
In fact, Scott said, hurricanes have been getting started an average of 500 kilometres further east since 1970, spending more time over warmer water.
While there are other factors involved in hurricane formation, the much larger pool of warm "birthing" waters also means storms can become stronger, since warm water provides fuel for them to grow.
Scott is convinced that global warming has made hurricanes more powerful.
"Humanity has had a discernible impact on hurricanes," he said in media reports.
That remains a controversial view -- but the data is mounting.
There is convincing new evidence that global warming will produce more powerful winter storms over the mid-latitudes of the Northern and Southern hemispheres, Steven Lambert, a climate expert at the Meteorological Service of Canada, told the conference.
Lambert examined how future greenhouse gas emissions will affect low pressure systems during the winter using nearly all of the most current computer climate models. The models all concurred that as levels of greenhouse gases in the atmosphere rise, low pressure systems, or cyclones as they're called, become stronger but form less often.
"There's a direct relationship between the changes in magnitude of cyclonic events and concentration of greenhouse gases," Lambert said in an interview.
Lambert told IPS that this affect is likely the result of higher temperatures triggering higher rates of evaporation. This means more latent heat is available, resulting in stronger lower pressure systems. Once those huge systems lose all their energy, it may take longer to form news ones, and that may be why the models show fewer cyclones, he said.
Finally, attempts to get the ocean to absorb more carbon dioxide, the main greenhouse gas, to slow the rate of global warming appear to have failed.
Around the world, several large-scale experiments, including a Canadian-led international effort off the coast of Alaska, dumped tonnes of iron particles into parts of the ocean to encourage phytoplankton growth. Plankton growth is limited by the amount of iron in parts of the world's oceans and the plankton growth in the Canadian experiment was visible from the ship and from satellites in space, said Paul Harrison, director of the Atmospheric, Marine and Coastal Environment programme at the University of Hong Kong.
The idea behind these efforts is that plankton absorb carbon dioxide and when they die, they sink to the bottom of the ocean, effectively trapping the CO2 forever. And while the uncounted trillions of microplankton creatures like diatoms can remove quite a lot of CO2 from the atmosphere, very little of that CO2 in the iron "seeding" experiments ended up deep in the ocean.
"This is the first comprehensive measure of the fate of an iron-induced plankton bloom," Harrison said.
The iron-induced plankton had chemical markers in each so their ultimate fate could be tracked. Less than five percent ended up below 120 metre, a depth at which the CO2 would be trapped for a long time, he said.
"It doesn't appear that this will be a very efficient way of reducing CO2 levels," Harrison concluded.
Copyright © 2006 IPS-Inter Press Service
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