I receive the AARP Bulletin (something I swore I would never do – but I thought I could get some good discounts for traveling). The April 2007 Bulletin had an interesting article about the expanding “50-degree comfort zone” in our country.
The area of the United States averaging 50 degrees has been slowly creeping northward.
The chart above is of the central region of the United States over a 25 year-period of time for the month of April. The green line indicates a trend of a rising temperature. All six months in the cooler half of the year – October, November, December, January, February, March, and April – show an increase in the average temperature over the 25-year period. The charts can be constructed by visiting NOAA‘s home page and selecting “climate” in the site box on the left side of the home page or in the lower portion of the home page.
The AARP article notes that in 1979 the 50-degree zone covered the lower southern states and stopped at the southern border of Illinois and Indiana and the west half of Kentucky. In 2006, the boundary line crept up to include one half of the State of Illinois and one third of the State of Indiana and the entire State of Kentucky.
For snowbirds who are rethinking their yearly trek to Florida, this is good news, but for the region itself, even a rise of three or four degrees in temperature can bring dramatic changes in the environment. The change in temperature not only affects regions such as our central region but also impacts the Earth as a whole. The following pictures were taken in Glacier Bay National Park and Reserve’s White Thunder Ridge. Muir Glacier has retreated out of the field of view, Riggs Glacier has thinned and retreated significantly, and dense new vegetation has appeared. Muir Glacier was more than 2,000 feet thick in 1941. 2004 USGS photo by B. F. Molnia; 1941 photo by W. O. Field.
Muir Glacier on August 13, 1941
Muir Glacier on August 31, 2004
While many still stubbornly cling to their position that global warming is a myth, the scientific data reflecting regional and global change such as that provided by NOAA and other environmental agencies speaks for itself.