Global warming a real threat
2004-01-08 14:05
Paris - Over one million plants and animals - a quarter of all life on land - could become extinct in just decades due to man-made climate change, scientists say.
The main culprit for this change, they say in an article due out on Thursday in the British journal Nature, is greenhouse gases, which are churned out by automobiles and industry and trap heat in the earth's atmosphere.
"An immediate and progressive switch to technologies that produce little or no new greenhouse gases, combined with active removal of carbon dioxide from the atmosphere, could save a million or more species from extinction," lead author Chris Thomas, a biologist from University of Leeds, said in a statement.
Thomas's team studied six regions rich in biodiversity, representing 20% of the planet's land area, and made projections for the survival of 1 103 species between 1990 and 2050, using elaborate computer models.
Three scenarios for expected climate change were used in the computer models - a minimum expected total rise of between 0.8 and 1.7° by 2050; a mid-range scenario with total temperature increases of 1.8-2.0 degrees; and the maximum rise, when the Earth's average climes rise by over 2.0 degrees during the period.
Australia, one of the regions studied, would lose over half of its more than 400 butterfly species by 2050.
Brazil's Cerrado area, a savannah-type area with a wealth of plant and animal species, could lose between 39 and 48% of its flora - thousands of plants whose medical or scientific benefits will never be known.
The six regions studied by the scientists were Australia, Brazil, Costa Rica, Europe, Mexico and South Africa.
The head of the UN Environment Program, Klaus Toepfer, warned that "the figure of one million may be an underestimate", since it only counts the extinction of species due to climate change, without taking into account a "ripple effect" that could also kill off interdependent plants and animals.
Toepfer said humans would suffer from the consequences of global warning, the result of their dependence on fossil fuels.
Lee Hannah, a co-author of the study with the Washington-based Conservation International, said that species faced with a dangerously warm environment would naturally seek a cooler area, but this was no longer possible in many cases.
"If habitat destruction has already altered those habitats, the species will have no safe haven."
Not all of the million-plus species would disappear by 2050, Thomas said, but many would be in decline and en route to extinction.