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April 21, 2009

EGU: Shifting seasons?

Changes in the annual life cycles of plants and animals are a good footprint of climate change in middle latitudes. But it is a footprint that is less easy to detecet than melting sea ice or glacier retreat.

Eye-observations by millions of gardeners and nature lovers suggest that plants green and flower earlier in spring, and that leaves begin to colour and fall off later in autumn, than they did just a few decades ago. So where will we end then? Will pollen soon be in the air all year round - a nightmare for allergic persons?

Scientists such as Annette Wenzel, an eco-climatologist at the Technical University of Munich, use remote sensing technologies, models, and in-situ observations to study the response of plants to warming temperatures. But the corelation between warming and ‘phenology’ is less clear than one might expect.

One reason, says Wenzel, is that the European phenology network of around 8,000 observation sites is a rather unevenly distributed affair. The vast majority of sites are located in Germany and its neighboring countries, whereas the whole of Scandinavia has just a handful of sites, and Italy not a single one. To make matters worse, the species composition differs from site to site, making it difficult for scientists to define a Euroean-wide ‘green-up’ index.

Even extreme climatic events don’t provide a clear picture. Warm spells have become significantly more frequent in Europe during all seasons, and cold spells less fequent, from 1990 onward than prior to 1990. Wenzel has looked at how recent warm and cold spells affected the flowering of cherry and apple trees, and the sowing and harvest time of winter wheat. Fruit trees and wheat farmers do respond to climate anomalies, she found. But, again, the correlations where not excitingly strong.

Weather-related crop failures are not included at all in the European phenology database. Scientists trying to establish connections between crop failures and climate change rely mostly on anecdotal evidence and media reports.

Quirin Schiermeier

Posted by Quirin Schiermeier on April 21, 2009
Categories: European Geosciences Union | | Comments (0) | TrackBacks (0)

EGU: Seasonal climate forecasts found wanting

It’s a warm and sunny spring day today in Vienna can you guess then whether the coming summer will be colder or warmer than usual? Well, if you think that you hardly have more – though certainly not less - than a 50% chance of getting it right you’re, uhm, right. But guess what: Supercomputer-powered seasonal climate forecasts don’t do much better.

Seasonal climate predictions work relatively well only in the tropics. In Europe and North America their predictive skills are still pretty poorer, meaning that forecast and observed climatology are often two very different things. And in some regions seasonal forecasts are actually worse than plain guessing.

This means that seasonal climate forecasts don’t yet provide reliable, if any, guidance for farmers, tourism managers, forest fire fighters, or for me and you. The idea that slowly varying boundary conditions, such as sea surface temperature distribution, snow cover and soil moisture, push the climate in a certain direction is well-established. But statistical climatology is one thing, daily wheather is another.

Andreas Weigel of the Swiss Weather Service, a rising star in the seasonal forecast community, made a few suggestions here at the EGU as to how predictive skills could be improved. Using more than one climate model is one promising possibility, statistical post-processing an re-calibrating forecasts is another, he explained in his well-received medal award lecture today

In the same session, Marie Boisserie of Florida Stae University in Tallahassee reported that when she included realistic initial soil moisture conditions to a climate model it greatly improved its predictive skills. Two-month forecasts of summer temperatures and precipitation in the US were more than twice as accurate than without the precipitation-derived soil moisture data.

Problem is that as yet there exists no reliable global observational database of soil moisture.
All eyes are now on the European Space Agency’s Soil Moisture and Ocean Salinity (SMOS) mission, designed to observe soil moisture over the Earth's landmasses and salinity over the oceans, to be launched in June.

Quirin Schiermeier

Posted by Quirin Schiermeier on April 21, 2009
Categories: European Geosciences Union | | Comments (0) | TrackBacks (0)

April 20, 2009

EGU: Mountain high, climate change

A record number of 9,000 or so scientist has come to the always charming Austrian capital of Vienna for this year’s general assembly of the European Geosciences Union, the biggest such meeting this side of the Atlantic.

In search of some local colour I went this morning to a session on climate and mountain hydrology. Vienna, just like Munich, Milan, Grenoble and many other cities in vicinity to the Alps, depends on drinking water from mountain streams and reservoirs. The Alps are in fact a water tower for all the surrounding lowlands; and although there is no real water shortage, Alpine regions are highly sensitive to climate change.

Bruno Schädler of the University of Bern in Switzerland explained that a two degree increase in average temperature is equivalent to a 360 metres decrease in altitude. Total glacier area in the Alps is likely to decrease by more than 50% under this pretty realistic scenario. Projections are that more winter precipitation will fall in the form of rain, and less as snow, and that increased evapotransporation will reduce the amount of summer rainfall. All this will change the runoff regimes of Alpine rivers and streams, and hence the availability of water competing purposes including irrigation, hydropower, and tourism. But how, where and when these changes will come, and if they will bring more floods, or more low water, or both, is still extermely difficult to say. Regional climate models, for example, don’t represent complex Alpine topography, hydrology and meteorology, which differ from one valley or catchment area to the next.

Perhaps that explains why there is little, if any, adaptation to climate change happening in the Alps. Indeed, adaptation measures are driven by concrete events and economic requirements – such as lack of snow in a skiing ressort – rather than by climate change predictions. This is the result of ongoing regional case studies in six Alpine regions of Austria, Slovenia, Italy, France and Switzerland. Planning and management tools which consider climate change are almost totally absent, found Andrea Prutsch of Austria’s federal environmental agency, who coordinats the studies. Water-consuming artificial snow making is just one example of frequently happening cases of ‘maladaptation’. By and large, she said, adaptation to climate change in the Alps suffers from a widespread lack of data, monitoring and knowledge.

The science of climate change has come a long way. But this little Alpine saga shows that it has not yet arrived in the centre of society.

Quirin Schiermeier

Posted by Quirin Schiermeier on April 20, 2009
Categories: European Geosciences Union | | Comments (0) | TrackBacks (0)

April 07, 2009

National laboratory avoids Italy quake damage

The Gran Sasso National Laboratory, a particle physics research centre 15 km from L’Aquila in central Italy, has survived intact the earthquake that destroyed the historic town on 6 April and killed at least 180 people.

“Gran Sasso labs and experiments have not suffered consequences of the earthquake,” says Eugenio Coccia, the centre’s director. “But of course many staff have had their houses destroyed, like so many others who live in the region.” No scientist has been recorded among the dead.

Scientific experiments are being monitored, but no major experimental work will take place until after the Easter holiday, says Coccia. Normal scientific work will begin Tuesday 14 April.

The research centre investigates the properties of neutrinos and dark matter. Its large underground labs built deep inside the Gran Sasso mountain were designed to withstand powerful earthquakes. The epicentre of this one, measuring 6.3 on the Richter scale, was just 10 km west of the centre.

The main highway to the laboratories has been closed for safety reasons, as small quakes are still occurring. The centre has offered to shelter those left homeless by the quake in its surface facilities.

In the meantime, the centre has distanced itself from Giampaolo Giuliani who claims to have predicted the earthquake and says that his warning was ignored. Giuliani has developed and patented a radon detector which he says enables him to predict earthquakes by detecting the radioactive gas leaking from underground sources. However, earthquake and civil defence experts in Italy said that it is not possible to predict the time and location of an earthquake with that –or any other – method.

Giuliani is quoted in many media reports as being a Gran Sasso staff member, but Caccia says this is not the case. “He is a technician in a collaboration with Gran Sasso which is based in Turin (in northern Italy) - his work on earthquakes is a hobby and nothing to do with the research project here.” Caccia says the research centre has been a “bit embarrassed” by the media reports.

Alison Abbott

Posted by Alison Abbott on April 07, 2009
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