NASA rings new global warming alarm bell; US has warmest summer since the Dust Bowl era

Two new NASA studies are raising alarm bells about global warming.

Scientists with the space agency have found that there is a decline in the amount of arctic sea ice in the winter. Their findings also show the decline is occurring at a faster rate.

Meanwhile, the National Oceanic and Atmospheric Administration said 2006 was the warmest summer in the U.S. since the Dust Bowl in the 1930s -- and the second warmest since the record keeping began in 1895.

Scientists say global warming causing more violent hurricanes

A new study reports stronger links between human-caused global warming and rising ocean temperatures -- a key factor in the development and growth of hurricanes.

The new study was done by researchers at Lawrence Livermore lab in California.

''We've now learned that the human-induced buildup of greenhouse gases in the atmosphere appears to be the primary driver of increasing hurricane activity,'' Robert Corell, an oceanographer and a researcher for the American Meteorological Society, said during a press conference to promote the study.

The findings were published Monday in the latest issue of the Proceedings of the National Academy of Sciences.