Earth's Tropics Belt Expands

[Newsjock]

Source: Associated Press

Earth's tropical belt seems to have expanded a couple hundred miles over the past quarter century, which could mean more arid weather for some already dry subtropical regions, new climate research shows.

Geographically, the tropical region is a wide swath around Earth's middle stretching from the Tropic of Cancer, just south of Miami, to the Tropic of Capricorn, which cuts Australia almost in half. It's about one-quarter of the globe and generally thought of as hot, steamy and damp, but it also has areas of brutal desert.

To meteorologists, however, the tropics region is defined by long-term climate and what's happening in the atmosphere. Recent studies show changes that indicate an expansion of the tropical atmosphere.

The newest study, published Sunday in the new scientific journal Nature Geoscience, shows that by using the weather definition, the tropics are expanding toward Earth's poles more than predicted. And that means more dry weather is moving to the edges of the tropics in places like the U.S. Southwest.

Independent teams using four different meteorological measurements found that the tropical atmospheric belt has grown by anywhere between 2 and 4.8 degrees latitude since 1979. That translates to a total north and south expansion of 140 to 330 miles.

Read more: http://www.sfgate.com/cgi-bin/article.cgi?file=/n/a/2007/12/02/national/a101129S58.DTL

[Barrett808]

1. "You're not expanding the tropical jungles, what you're expanding is the area of desertification."

Yup.

[Labors of Hercules]

2. not to mention...

tipping arid regions where life is already precarious into total uninhabitability, putting countless species at even greater risk than they already are.

[alfredo]

8. I saw that happening in Eritrea. The Sahara has been expanding for

many decades.

[NutmegYankee]

3. It's not the tropics that matter, but the Subtropical High.

http://en.wikipedia.org/wiki/Horse_latitudes
http://www.newmediastudio.org/DataDiscovery/Hurr_ED_Center/Easterly_Waves/Trade_Winds/Trade_Winds.html

The tropics are a low pressure zone, and air rises and travels north and south before falling into a semipermanent high zone that is commonly called the Subtropical high or the horse latitudes. This zone shifting is the problem, since it will expand the deserts farther into the temperate regions.

Bad news.

[Odin2005]

5. So this is basically the trade winds zone expanding poleward? n/t.

[NutmegYankee]

11. Yes. But its the dry "Horse Latitude" that will hurt.

Notice most of the earth's deserts are around 30 degrees N and S.

[FatDave]

4. 140 to 330 miles in 25 years??!!

That's alarming. 25 years is a nanosecond, geologically speaking. We may well be irreversibly fucked.

[tom_paine]

10. I believe you have reached the heart of the matter

n/t

[Odin2005]

6. This is very concerning. I'm expecting other zones to start shifiting northward soon.

For example, here in Minnesota as the winters get milder the conifers of the northern evergreen forest in the northern part of the state will start to be out-competed by the less cold-tolerant white pine and red pine and broad-leaf trees like maple, oak, and basswood. I'm expecting, at the very latest, that the "North Woods" witll have mostly shifted northward out of Minnesota by end of the century. Some old spruces and firs might hold on, but there will be few if any younger individuals of such tree species.

[tabasco]

7. I call it the "giant flying cockroach zone."

With the warm weather come the bugs.

[loves_dulcinea]

9. very apt!

well spoken.