Tropical Belt Widening
Research by a NOAA scientist and colleagues has determined that the Earth's tropical belt (area between the tropic of Cancer and the tropic of Capricorn) has widened over the past 25 years as the planet warmed. The team compared upper-air measurements and computer model simulations to come this conclusion. Some observational studies have already found a widening of the tropics by several degrees latitude since 1979, according to the NOAA article.
"We looked at how certain aspects of the structure and circulation of the atmosphere have been altered over the past few decades and how models predict they may change as the climate changes in the future,” said Dian Seidel, lead author and research meteorologist with NOAA’s Air Resources Laboratory in Silver Spring, Md. “We are seeing indications that a warming climate is associated with expansion of the tropical region toward the poles, and the rate of expansion that has occurred in recent decades is greater than projected by climate models to occur in the 21st century."
Keep in mind, there are still a lot of unanswered questions as to what specific global warming mechanisms are causing this expansion. Some of those possibilities are warming sea surface temperatures, stratospheric ozone depletion and even changes in the El Nino Southern Oscillation system.
The findings of this study were just published in Nature Geoscience.
