Associated Press Writer John Heilprin reports that a study by the National Academy of Sciences and requested by Congress to address those who have questioned global warming as a major threat, reached the conclusion that Earth has experienced an unprecedented warmth in the last 400 years, if not longer.
The Earth is running a slight fever from greenhouse gases, after enjoying relatively stable temperatures for 2,000 years. The National Academy of Sciences, after reconstructing global average surface temperatures for the past two millennia, said Thursday the data are "additional supporting evidence ... that human activities are responsible for much of the recent warming."
Other new research showed that global warming produced about half of the extra hurricane-fueled warmth in the North Atlantic in 2005, and natural cycles were a minor factor, according to Kevin Trenberth and Dennis Shea of the National Center for Atmospheric Research, a research lab sponsored by the National Science Foundation and universities.
The academy had been asked to report to Congress on how researchers drew conclusions about the Earth's climate going back thousands of years, before data was available from modern scientific instruments. The academy convened a panel of 12 climate experts, chaired by Gerald North, a geosciences professor at Texas A&M University, to look at the "proxy" evidence before then, such as tree rings, corals, marine and lake sediments, ice cores, boreholes and glaciers.
Stopping global warming has become a major focus in the California legislature this year and effective solid waste management and increasing recycling can help. Greenhouse gas emissions exist not only from cars, but from landfills as well, making your everyday choices important as we must continue to reduce our waste and increase recycling rates.
What You Can Do: