[D66] '..very likely' == 'evidence' ?

[Henk Elegeert]

Climate change and extreme flooding linked by new
evidence<http://www.guardian.co.uk/environment/georgemonbiot/2011/feb/16/climate-change-extreme-weather>

Two studies suggest for the first time a clear link between global warming
and extreme precipitation

[image: Australia-Flooding-007[1].jpg]

Flood waters submerge homes in the town of Ipswich, west of Brisbane, in
this year's extreme flooding in Australia. Photograph: Dave Hunt/AAP/Press
Association Images


There's a sound rule for reporting
weather<http://www.guardian.co.uk/uk/weather>events that may be
related to climate
change <http://www.guardian.co.uk/environment/climate-change>. You can't say
that a particular heatwave or a particular downpour – or even a particular
freeze – was definitely caused by human emissions of greenhouse gases. But
you can say whether these events are consistent with predictions, or that
their likelihood rises or falls in a warming world.

Weather is a complex system. Long-running trends, natural fluctuations and
random patterns are fed into the global weather machine, and it spews out a
series of events. All these events will be influenced to some degree by
global temperatures, but it's impossible to say with certainty that any of
them would not have happened in the absence of man-made global warming.

But over time, as the data build up, we begin to see trends which suggest
that rising temperatures are making a particular kind of weather more likely
to occur. One such trend has now become clearer. Two new papers, published
by Nature, should make us sit up, as they suggest for the first time a clear
link between global warming and extreme precipitation (precipitation means
water falling out of the sky in any form: rain, hail or snow).

One paper, by Seung-Ki Min and
others,<http://www.nature.com/nature/journal/v470/n7334/full/nature09763.html>shows
that rising concentrations of greenhouse gases in the atmosphere have
caused an intensification of heavy rainfall events over some two-thirds of
the weather stations on land in the northern hemisphere. The climate models
appear to have underestimated the contribution of global warming on extreme
rainfall: it's worse than we thought it would be.

The other paper, by Pardeep Pall and
others,<http://www.nature.com/nature/journal/v470/n7334/full/nature09762.html>shows
that man-made
global warming is very likely to have increased the probability of severe
flooding in England and
Wales,<http://www.guardian.co.uk/environment/2011/feb/16/climate-change-risk-uk-floods>and
could well have been behind the extreme events in 2000. The
researchers
ran thousands of simulations of the weather in autumn 2000 (using idle time
on computers made available by a network of
volunteers<http://www.guardian.co.uk/environment/2010/nov/17/weatherathome-climate-change-weather-project>)
with and without the temperature rises caused by man-made global warming.
They found that, in nine out of 10 cases, man-made greenhouse gases
increased the risks of
flooding<http://www.guardian.co.uk/environment/flooding>.
This is probably as solid a signal as simulations can produce, and it gives
us a clear warning that more global heating is likely to cause more floods
here.

None of this should be surprising. As Richard Allan points out, also in
Nature, <http://www.nature.com/nature/journal/v470/n7334/full/470344a.html>the
warmer the atmosphere is, the more water vapour it can carry. There's
even a formula which quantifies this: 6-7% more moisture in the air for
every degree of warming near the Earth's surface. But both models and
observations also show changes in the distribution of rainfall, with
moisture concentrating in some parts of the world and fleeing from others:
climate change is likely to produce both more floods and more droughts.

We still can't say that any given weather event is definitely caused by
man-made global warming. But we can say, with an even higher degree of
confidence than before, that climate change makes extreme events more likely
to happen.

monbiot.com<http://www.guardian.co.uk/environment/georgemonbiot/2011/feb/16/www.monbiot.com>

"

'... is very likely' heet dan plots 'evidence' ?

En (veel) vroeger zorgde god -die niet bestaat- zelf nog voor de diverse
rampen?

"But we can say, with an even higher degree of confidence than before, that
climate change makes extreme events more likely to happen." ? Blijkens? Want
opnieuw: geen bewijs, slechts aannames. Zelfs geen werkelijke beschrijvingen
over wat die "extreme events" nu precies inhouden ... of wat hier werkelijk
man-made of variabel natuurlijk proces is.

Henk Elegeert
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