Seasonal melting this year in the higher altitudes of the Greenland Ice Sheet rose 150% above the 19-year average, according to a news release from NASA. Melting also took place on 25-30 more days than the average.

The large image on the link shows the melt anomaly of Greenland for 2007. The anomaly is measured as the difference between the number of days on which melting occurred in 2007 compared to the average annual melting days over the last 19 years. The red colors indicate more melt days than normal, while the blue is obviously less than normal. The image was made using microwave-frequency data from the Defense Meteorological Satellite Program.

Marco Tedesco, a scientist at the Joint Center for Earth Systems Technology also calculated a melting index. The index is determined by multiplying the number of days that melting took place by the area where melting occurred. The melting insex in the lower altitude ice sheet areas of Greenland during 2007 was 30% higher than average. Taking into account the entire Greenland Ice Sheet, the melting index for 2007 was the 5th highest on record, following 2005, 2002,1998 and 2004.

In a debate before an Institute of Medicine Panel on Global Health, top climate change scientists argued Tuesday whether or not there is concrete evidence linking global warming to the spread of infectious disease.

In the Boston Globe article written by John Donnelly, Mr. Donald S. Burke, dean of Pittsburgh's Graduate School of Public Health, noted that a 2001 study found that weather fluctuation and seasonal variability may influence the spread of infectious disease. But he believes that such conclusions should be interpreted with caution. "There are no apocalyptic pronouncements," Burke said. "There's an awful lot we don't know." Burke said he is not convinced that climate change can be proven to cause the spread of many diseases, specifically naming dengue fever, influenza, and West Nile virus.

On the other hand, you have Paul R. Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School, who said clusters of disease outbreaks spread by water, mosquitoes, and rats could clearly be traced to global warming. Epstein said those who "just look at specific diseases can miss the broader picture. If you look at ecological systems, water systems, the extreme weather, the range of wildlife . . . or more profoundly everything that supports a health system, then you can see the linkages. Scope is really important when you look at this."

An example of a documented link of disease to a chnaging weather pattern was exhibited by an earlier outbreak of chikungunya fever along Kenya's coast. Weather patterns caused by La Nina led to drought in east Africa during 2004. Because there was a shortage of fresh water, people rarely emptied buckets around their homes, giving mosquitoes an ideal breeding ground of standing water.

"An outbreak like that is from a convergence of factors, and climate is one of them," said Jean-Paul Chretien, who is the Defense Department's coordinator of overseas laboratories.