Global warming sowing disease, extinctions, researchers say.

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Global warming sowing disease, extinctions, researchers say

Jan. 11, 2006

Special to World Science

http://www.world-science.net/othernews/060111_warmingfrm.htm

 

Global warming has triggered epidemics that killed off dozens of amphibian

species in tropical America, and is fomenting disease among other animals,

researchers say.

 

 

Still with us, for now: The Panamanian golden frog, Atelopus

Zeteki, one of the 110 or so species of harlequin frogs, a genus known from 11

tropical American countries. Unlike some harlequin frogs, this one isn't extinct

yet, but its populations have dropped, researchers say. (Courtesy Forrest Brem).

 

 

 

 

It’s all part of an unpredictable spiral of warming-induced epidemics, they

add—and there are signs that the phenomenon is starting to touch humans, who are

far from immune to it.

 

A study published in the Jan. 12 issue of the research journal Nature reported

that global climate change created favorable conditions for a deadly fungus in

Central and South America. That led to widespread frog extinctions in

mountainous areas.

 

Thousands of amphibian species have declined, and hundreds are on the brink of

extinction or have already vanished, a group of 14 researchers said in the

paper.

The fungus has killed off some two thirds of the 110 species of a colorful

group known as harlequin frogs, they estimated.

That, they suggested, shows the climate change is killing off animals through

more complex mechanisms than just higher temperatures—although studies have

found that’s happening, too.

 

Scientists believe global warming is largely a result of industrially released

gases that trap heat in the atmosphere. An international pact to curb these

emissions, the Kyoto Protocol, has encountered resistance from the United States

and other countries on grounds that the limits would harm their economies.

 

The authors of the Nature study, led by Alan Pounds of Costa Rica’s Monteverde

Cloud Forest Preserve and Tropical Science Centre, said climate change is

promoting infectious disease and destroying species.

In a commentary in the same issue of Nature, scientists said the amphibian

crisis is just one example of unexpected, complex impacts from climate change

that are becoming increasingly obvious.

 

The crisis is “an amphibian alarm call” and a harbinger of much worse

disruption, said the researchers, Andrew R. Blaustein of Oregon State University

in Corvallis, Ore. and Andy Dobson of Princeton University in Princeton, N.J.

 

Extinctions that once seemed puzzling are now believed to be linked to global

warming, they added.

 

“The powerful synergy between pathogen transmission and climate change should

give us cause for concern about human health in a warmer world,” said the

university’s Andrew Blaustein in the Nature article. “As global change is

occurring at an unprecedented pace, we should expect many other host taxa

[organisms], from ants to zebras, to be confronted with similar challenges.”

 

Few of current studies consider how climate affects disease, said the

researchers, and until this happens it will be hard to gauge global warming’s

full effects.

 

Five years ago, in a study also published in Nature, scientists from the Oregon

State University also found that warming and other climate changes in the

Pacific Northwest of the United States were resulting in lowered water depths in

mountain lakes, killing off many toads before birth.

 

“The climate change in the Arctic and sub-Arctic has modified the life cycle of

the nematode parasites of musk oxen,” wrote Blaustein and Dobson. “These worms

can now complete their life cycle in one year, instead of two, and their rising

numbers are having a significant impact on musk oxen survival.”

A life cycle is the period between birth and reproduction, and when it’s

shorter, an organism can spread more quickly, Blaustein said. “They can do more

damage in much less time.”

 

Similarly, Blaustein said, the mountain pine beetle in parts of the western

United States is completing its life cycle in one year, instead of two, leading

to increasing problems with the fungus they carry.

 

Dengue fever, a deadly disease of humans, is increasing its range out of the

tropics and is now found in parts of the southern United States, he added.

Dengue fever is carried by mosquitoes who transmit any of four related dengue

viruses. It was once called break-bone fever because it sometimes causes severe

joint and muscle pain that feels like the bones are breaking. It sometimes kills

younger victims.

 

Predicting how climate change will favor a certain pathogen or disease

transmission is extremely hard, Blaustein and Dobson said: “We should expect the

unexpected.”

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" Our ideal is not the spirituality that withdraws from life but the conquest

of life by the power of the spirit. " - Aurobindo.

 

 

 

 

 

 

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