Tropics Expanding

The Earth's tropical zone is expanding thanks to climate change.

Researchers at James Cook University concluded the tropics had widened by up to 500 kilometres (310 miles) in the past 25 years after examining 70 peer-reviewed scientific articles.

They looked at findings from long-term satellite measurements, weather balloon data, climate models and sea temperature studies to determine how global warming was impacting on the tropical zone.

The findings showed it now extended well beyond the traditional definition of the tropics, the equatorial band circling the Earth between the Tropic of Cancer and the Tropic of Capricorn.

As usual, I am less concerned about what will happen in the subtropics than what will happen at the other ends, the Arctic and Antarctic. Organisms in zones towards the middle of the planet should have an easier time adjusting or shifting their ranges than ones at the extremes, where there is really no place to go. However, an expanded tropical zone does come with severe consequences, such as more virulent diseases (such as malaria and dengue fever) and more extreme weather patterns. So this trend is definitely disturbing.