Tropical climate zones are expanding poleward

Earth's tropical regions, which are generally characterized by high average temperatures and heavy rainfall, are expanding poleward, according to a new study published in the American Geophysical Union's (AGU) journal of Geophysical Research.

Earth's tropical climate zones shown in blue based on 1980-2016 climate data. Image courtesy Wikipedia.

However, the leading edges of these tropical climate zones are typically hot and dry.

These leading edges of the tropical climate zones have expanded over the past 15 years, with the greatest advancement occurring in the Southern Hemisphere, according to the AGU report.

Based on satellite observations, the tropical zones are advancing at a rate of 0.25 to 0.50 degrees latitude per decade. Researchers are still uncertain if this rate will increase, decrease or remain the same over the coming decades.

The trigger for this expansion is likely a result of ocean warming due to climate change, which also helps explain the greater expansion into the Southern Hemisphere which has a much larger water surface than the Northern Hemisphere.

Potential impacts of this expansion are more extreme wildfires and larger and more severe droughts in places such as Australia and California.

Key excerpt from the report.....

"While natural long-term climate fluctuations contribute to the observed trends, these variations alone cannot explain the extent to which expansion has already occurred."