permaculture

[Lawrence London <lfljvenaura@gmail.com>]

*http://www.princeton.edu/main/news/archive/S32/13/25I02/index.xml
* Erratic, extreme day-to-day weather puts climate change in new light
Posted November 15, 2011; 03:00 p.m.
share<http://www.addtoany.com/share_save#url=http%3A%2F%2Fwww.princeton.edu%2Fmain%2Fnews%2Farchive%2FS32%2F13%2F25I02%2Findex.xml%3Fsection%3D&title=Princeton%20News%3A%20Erratic%2C%20extreme%20day-to-day%20weather%20puts%20climate%20change%20in%20new%20light&description=>|
e-mail<http://www.addtoany.com/email?linkurl=http://www.princeton.edu/main/news/archive/S32/13/25I02/index.xml?section=&linkname=Princeton%20News:%20Erratic,%20extreme%20day-to-day%20weather%20puts%20climate%20change%20in%20new%20light>|
printby Morgan Kelly

The first climate study to focus on variations in daily weather conditions
has found that day-to-day weather has grown increasingly erratic and
extreme, with significant fluctuations in sunshine and rainfall affecting
more than a third of the planet.

Princeton University researchers recently
reported<http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI4115.1>in
the Journal of Climate that extremely sunny or cloudy days are more
common than in the early 1980s, and that swings from thunderstorms to dry
days rose considerably since the late 1990s. These swings could have
consequences for ecosystem stability and the control of pests and diseases,
as well as for industries such as agriculture and solar-energy production,
all of which are vulnerable to inconsistent and extreme weather, the
researchers noted.

The day-to-day variations also could affect what scientists can expect to
see as the Earth's climate changes, according to the researchers and other
scientists familiar with the work. Constant fluctuations in severe
conditions could alter how the atmosphere distributes heat and rainfall, as
well as inhibit the ability of plants to remove carbon dioxide from the
atmosphere, possibly leading to higher levels of the greenhouse gas than
currently accounted for.

Existing climate-change models have historically been evaluated against the
average weather per month, an approach that hides variability, explained
lead author David
Medvigy<http://www.princeton.edu/geosciences/people/medvigy/>,
an assistant professor in the Department of
Geosciences<http://www.princeton.edu/geosciences/>at Princeton. To
conduct their analysis, he and co-author Claudie
Beaulieu <http://www.princeton.edu/aos/people/research_staff/beaulieu/>, a
postdoctoral research fellow in Princeton's Program in Atmospheric and
Oceanic Sciences <http://www.princeton.edu/aos>, used a recently developed
computer program that has allowed climatologists to examine weather data on
a daily level for the first time, Medvigy said.

"Monthly averages reflect a misty world that is a little rainy and cloudy
every day. That is very different from the weather of our actual world,
where some days are very sunny and dry," Medvigy said.

"Our work adds to what we know about climate change in the real world and
places the whole problem of climate change in a new light," he said.
"Nobody has looked for these daily changes on a global scale. We usually
think of climate change as an increase in mean global temperature and
potentially more extreme conditions -- there's practically no discussion of
day-to-day variability."