[NYTr] Why So Wet? Climate change 'triggering increased rainfall

[nytr at olm.blythe-systems.com]

sednt by Tim Murphy

IN THE NEWS - Jul 23, 2007
http://www.inthenews.co.uk/news/autocodes/countries/russia/climate-change-triggering-increased-rainfall-$1112788.htm

Climate change 'triggering increased rainfall 

Scientists have found for the first time that human-induced climate
change has triggered significant shifts in precipitation such as
increased rain and snowfall either side of the equator.

Previous studies have already linked global warming to changes in
surface air temperature and rising sea levels and temperatures.

The latest finding is based on international research which studied the
link between human actions and precipitation (any product of
atmospheric vapour).

Researchers from Environment Canada and six research centres in the UK,
Japan and US charted changes in greenhouse gases (GHG) and sulphate
aerosol concentrations in the atmosphere along with global
precipitation during the past century.

GHG and sulphate aerosols are produced primarily by burning fossil
fuels.

Most of the increased precipitation was found to take place 50 degrees
north of the equator in areas including Canada, Europe and Russia as
well as in the southern hemisphere.

Drying on the other hand increased in a region north of the equator
including Mexico, Central America and northern Africa.

Writing in the journal Nature, the scientists warn that these changes in
precipitation may already have had a negative effect throughout the
world.

"We estimate that anthropogenic forcing [man-made effects] contributed
significantly to observed increases in precipitation in the northern
hemisphere mid-latitudes, drying in the northern hemisphere subtropics
and tropics, and moistening in the southern hemisphere subtropics and
deep tropics," the researchers write.

"The observed changes, which are larger than estimated from model
simulations, may have already had significant effects on ecosystems,
agriculture and human health in regions that are sensitive to changes in
precipitation, such as the Sahel [region in northern Africa]."