Earth's tropics are expanding poleward and that expansion is driven by human-caused changes to the ocean, according to new research.
The tropics wrap around Earth's middle like a warm, wet belt. This part of the globe gets the most direct sunlight throughout the year and is characterized by high average temperatures and heavy rainfall. In contrast to the tropics' lush interior, however, this region's edges are hot and parched.
Scientists have noticed for the past 15 years that these arid bands are expanding toward the poles into regions like the Mediterranean, southern Australia and southern California. Interestingly, these dry areas have expanded more in the Southern Hemisphere than the Northern Hemisphere and researchers have struggled to pinpoint exactly what is driving the trend.
