Tropics in expansion by Claudia Sonea

The global warming is a serious issue and humanity has to deal with it. As a consequence of it, a new climate research shows that Earth's tropics have expanded a couple hundred miles over the past quarter century, leading to a more arid weather for some already dry subtropical regions. The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the Tropic of Cancer (south of Miami) in the northern hemisphere, at approximately 23°30' (23.5°) N latitude, and the Tropic of Capricorn (cuts Australia in half) in the southern hemisphere at 23°30' (23.5°) S latitude. It represents one-quarter of the globe and generally regarded as hot, steamy and damp with long-term climate from the point of view of the meteorologists. Published Sunday in the new scientific journal Nature Geoscience, the newest study about the changes that took place in the atmosphere and the influence had on tropics reveals that the tropics are expanding toward Earth's poles more than predicted. As it is, the U.S. Southwest is affected by the changes with a more dry weather. According to their measurements, four different meteorological measurements made by independent teams, since 1979 the tropical atmospheric belt has grown between 2 and 4.8 degrees latitude, which means a total north and south expansion of 140 to 330 miles. One of the causes is Hadley circulation, which is essentially prevailing rivers of wind that move vertically as well as horizontally, carrying lots of moisture to rainy areas while drying out arid regions on the edges of the tropics. Others are the amount of ozone in the atmosphere, the depth of the lower atmosphere, and the level of dryness in the atmosphere at the edges of the tropics. Dian Seidel, a research meteorologist with the National Oceanic and Atmospheric Administration lab in Silver Spring and author of the study stated that the expansion is a lot bigger than expected and that there is no way of knowing if it's a temporary expansion or the exact causes. Andrew Weaver of the University of Victoria and Richard Somerville of the Scripps Institution of Oceanography comes in her support and shares the concerns that the desertification is the main effect of the tropics widening and that can only reflect negatively upon us, the humanity. Stay connected and protect the environment if you still want to enjoy it.

related story: http://news.yahoo.com/s/ap/20071202/ap_on_sc/expanding_tropics;_ylt=AmSiYoWsvbnoV04BOg3ZXbus0NUE

by Claudia Sonea for PocketNews (http://pocketnews.tv)

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