Earth's Endless Summer

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Earth's Endless Summer Causing More Disease

June 20, 2002 11:12:39 AM PST, HealthScout News

By Gardner

HealthScoutNews Reporter

THURSDAY, June 20 (HealthScoutNews) -- Perpetual summer is coming to Earth,

and it's not going to be an endless procession of beach parties and sea

breezes. As the world gets warmer, it's also likely to get sicker --

literally.

A two-year study out of the National Center for Ecological Analysis and

Synthesis (NCEAS) finds climate changes will likely mean an increase in

infectious diseases affecting both plant and animal systems, possibly

threatening the survival of entire species. The research appears in

tomorrow's issue of Science.

" This is a very important paper that brings together the issues of diseases

in plants and wildlife and humans. By looking at the cross-section, one gets

an even stronger picture of the impact of warming on disease, " says Dr.

Epstein, associate director of the Center for Health and the Global

Environment at Harvard Medical School. " One gets a very strong signal that

warming is certainly increasing and contributing to the emergence and

resurgence and redistribution of infectious diseases. "

This study is the first to investigate disease epidemics across entire plant

and animal systems.

" We're looking for general patterns across as many diseases of as many

organisms as possible, including oysters, coral, plants and songbirds, and

we're seeing striking similarities in the patterns of disease spread, " says

Ostfeld, co-author of the study and an animal ecologist at the

Institute of Ecosystem Studies in Millbrook, N.Y. " The similarities are

striking enough across the board that we think this has to be taken

seriously now. "

The study authors began their research with two known developments: the

warming of the earth's climate and the fact that certain diseases, such as

malaria and Dengue fever, are spreading northward from the tropics and up

into mountains.

The question then became: How are these two linked? And the answer: Possibly

in several different ways.

Pathogens, microorganisms and vectors such as mosquitoes tend to flourish in

higher temperatures. In the Hawaiian Islands, for example, mosquitoes used

to stay below 2,500 feet, where it was warmer. Now, thanks to global

warming, they've moved up in to the mountains where they are threatening the

last populations of honeycreepers (songbirds unique to Hawaii) with avian

malaria.

Reproduction and biting also both tend to increase in hotter areas. Winter

acts as a curb on population growth.

Warmer weather may also make hosts more susceptible to infection.

The spread of disease may not come from the warming per se, but from changes

in rainfall patterns and humidity caused by the higher temperatures. For

example, Rift Valley fever, a virus spread by mosquitoes, is strongly linked

to heavy rains. " One disturbance sets you up for further disturbances, "

Epstein says. " Once the system is disrupted, it's more vulnerable. "

Biodiversity is also suffering, as pathogens contribute to declining numbers

of lions, cranes and vultures, to name a few.

" We've underestimated the rate at which climate would change, the rate at

which biological systems would respond to that change, the cost to our

society and to our agriculture, to our forest, to our health from all of

this, " Epstein says.

Believe it or not, the news could have a silver lining.

" The good news is that this may serve as a wake-up call, " he continues.

" This can lead us to address how we're developing, and how we power that

development. I don't want to say it's too late. I like to think that systems

can be restabilized. "

Earlier this month, the Bush administration reversed course and acknowledged

in a report to the United Nations that human activity is largely responsible

for global warming. However, the administration still opposes a treaty aimed

at cutting greenhouse gases, and doesn't plan to follow the report's

recommendations aimed at halting the problem.

What To Do

For more information on global warming, check out Global Warming: Early

Warning Signs or the Environmental Protection Agency.