Global Warming 2020

Global Warming News : Satellites Can Help Arctic Grazers Survive Killer Winter Storms

Rain falling on snow sounds like a relatively harmless weather event, but when it happens in the far north it can mean lingering death for reindeer, musk oxen and other animals that normally graze on the Arctic tundra.

That was the case in October 2003 on Canada’s Banks Island, at the edge of the Beaufort Sea inside the Arctic Circle. Rain fell for several days on top of a 6-inch snow cover, and the rain seeped through the snow to the soil surface. The temperature then plunged and the water became a thick layer of ice that lasted the winter and prevented browsing animals from reaching their food supply of lichens and mosses at the soil’s surface. Some 20,000 musk oxen starved to death.

“Starvation happened over a period of many months and no one knew until they went up to do the population count the next spring,” said Thomas Grenfell, a University of Washington research professor of atmospheric sciences who has studied the Banks Island event.

Grenfell and Jaakko Putkonen, a UW research associate professor of Earth and space sciences, have found evidence of the 2003 rain-on-snow occurrence in passive satellite microwave imagery, which they believe could provide a signature to help detect such events anywhere. They detail their work in a paper to be published March 25 in Water Resources Research, a journal of the American Geophysical Union.

Their methods could provide native people, whose livelihood depends on hoofed animals such as musk oxen, reindeer and caribou with a realistic chance of getting food to the herds to prevent mass starvation.

“We are talking about Banks Island, but this applies to the whole Arctic — Alaska, northern Canada, Siberia, Scandinavia — wherever there is permafrost,” Putkonen said.

Grenfell has conducted more than 40 field experiments in polar regions and has become quite familiar with precipitation characteristics there. Much of the previous work he did was with researchers who were interested in the nature of the snowpack, but he found that the presence of water interfered with interpreting satellite microwave readings.

But for the new research, the signal from water was key. Grenfell and Putkonen looked for patterns in satellite microwave data that correlated with rain-on-snow events. They examined data from 10 different satellite microwave channels, each providing slightly different information on the condition of the snowpack.

“The subtleties in the microwave levels mean there can be high error margins on this information, but the Banks Island event stood out like a sore thumb in the data,” Grenfell said.

The researchers hope to examine other satellite microwave records in search of evidence of rain-on-snow events during the last 30 years that are known from anecdotal information.

The 2003 rain-on-snow event affected the northern part of the 43,000-square-mile Banks Island. The musk oxen population of 70,000 was cut by nearly 30 percent, but a caribou herd on the southern part of the island was unaffected. The closest weather station, about 60 miles from the musk oxen range, didn’t record any rainfall at the time of the event that resulted in the massive die off, so few people recognized that the oxen were in distress.

Currently there is no way to know exactly where or how often these potentially devastating rain-on-snow events occur, the researchers say, but using satellite data to locate them could make up for a scarcity of weather stations in the sparsely populated Arctic.

Rain-on-snow events historically have occurred mostly in coastal areas. However, in earlier research Putkonen found that models predict that climate change will push winter rainfall much farther into northern continents and large islands.

While food shortages can trigger a large die off, there also can be severe consequences from milder events that force animals to exert more energy to get food. That reduces body weight and limits reproduction, which in turn can cause long-term damage to herds.

“Because the Arctic stays well below freezing for eight to 10 months of the year, the ice layer can stay around for months. If a rain-on-snow event happens in the fall, these animals can go the whole winter without access to food,” Putkonen said. “The native people in the north depend on these animals for food and for many other things.”

Adapted from materials provided by University of Washington.

Source: http://www.sciencedaily.com/releases/2008/03/080318121552.htm

Global Warming News : Satellite Makes First Ever Observation Of Regionally Elevated Carbon Dioxide From Manmade Emissions

Using data from the SCIAMACHY instrument aboard ESA’s Envisat environmental satellite, scientists have for the first time detected regionally elevated atmospheric carbon dioxide – the most important greenhouse gas that contributes to global warming – originating from manmade emissions.

More than 30 billion tonnes of extra carbon dioxide (CO2) is released into the atmosphere annually by human activities, mainly through the burning of fossil fuels.

According to the latest report by the Intergovernmental Panel on Climate Change (IPCC), this increase is predicted to result in a warmer climate with rising sea levels and an increase of extreme weather conditions. Predicting future atmospheric CO2 levels requires an increase in our understanding of carbon fluxes.

Dr Michael Buchwitz from the Institute of Environmental Physics (IUP) at the University of Bremen in Germany and his colleagues detected the relatively weak atmospheric CO2 signal arising from regional ‘anthropogenic’, or manmade, CO2 emissions over Europe by processing and analysing SCIAMACHY data from 2003 to 2005.

As illustrated in the image, the findings show an extended plume over Europe’s most populated area, the region from Amsterdam in the Netherlands to Frankfurt, Germany.

Carbon dioxide emissions occur naturally as well as being created through human activities, like the burning of fossil fuels (oil, coal, gas) for power generation, industry and traffic.

“The natural CO2 fluxes between the atmosphere and the Earth’s surface are typically much larger than the CO2 fluxes arising from manmade CO2 emissions, making the detection of regional anthropogenic CO2 emission signals quite difficult,” Buchwitz explained.

“This does not mean, however, that the anthropogenic fluxes are of minor importance. In fact, the opposite is true because the manmade fluxes are only going in one direction whereas the natural fluxes operate in both directions, taking up atmospheric CO2 when plants grow, but releasing most or all of it again later when the plants decay. This results in higher atmospheric CO2 concentrations in the first half of a year followed by lower CO2 during the second half of a year with a minimum around August.

“That we are able to detect regionally elevated CO2 over Europe shows the high quality of the SCIAMACHY CO2 measurements.”

Buchwitz says further analysis is required in order to draw quantitative conclusions in terms of CO2 emissions. “We verified that the CO2 spatial pattern that we measure correlates well with current CO2 emission databases and population density but more studies are needed before definitive quantitative conclusions concerning CO2 emissions can be drawn.”

Significant gaps remain in the knowledge of carbon dioxide’s sources, such as fires, volcanic activity and the respiration of living organisms, and its natural sinks, such as the land and ocean.

“We know that about half of the CO2 emitted by mankind each year is taken up by natural sinks on land and in the oceans. We do not know, however, where exactly these important sinks are and to what extent they take up the CO2 we are emitting, i.e., how strong they are.

“We also don’t know how these sinks will respond to a changing climate. It is even possible that some of these sinks will saturate or turn into a CO2 source in the future. With our satellite measurements we hope to be able to provide answers to questions like this in order to make reliable predictions,” Buchwitz said.

By better understanding all of the parameters involved in the carbon cycle, scientists can better predict climate change as well as better monitor international treaties aimed at reducing greenhouse gas emissions, such as the Kyoto Protocol which addresses the reduction of six greenhouse gases.

Last year, European Union leaders highlighted the importance of cutting emissions from these manmade gases by endorsing binding targets to cut greenhouse gases by at least 20 percent from 1990 levels by 2020.

Adapted from materials provided by European Space Agency.

Source: http://www.sciencedaily.com/releases/2008/03/080318110330.htm