Earth’s tropical region, as defined by rain and wind patterns, expanded north and south over the past few decades, another sign of global climate change, researchers reported today. The tropics have moved toward the poles at a faster rate than existing models of climate change have predicted, the scientists wrote in the journal Nature Geoscience.
To astronomers and mapmakers, the tropics are bordered by the Tropics of Cancer and Capricorn, which fall at about 23.5 degrees north and south of the equator. Climatologists tend to measure the area differently, using changes in atmospheric temperatures, winds and ozone observations.
Seidel’s team of climatologists reviewed recent research on the width of the tropical belt. They found that the tropics had expanded north and south by about 2.5 degrees in latitude over the past 25 years. Under the most extreme climate change model, the tropics were forecast to move 2 degrees by the end of this century, the researchers said.