Reuters, Dec. 23 2009
LOS ANGELES (Reuters) - Earth's various ecosystems, with all their plants and animals, will need to shift about a quarter-mile per year on average to keep pace with global climate change, scientists said in a study released on Wednesday.
How well particular species can survive rising worldwide temperatures attributed to excess levels of heat-trapping "greenhouse" gases emitted by human activity hinges on those species' ability to migrate or adapt in place.
The farther individual species -- from shrubs and trees to insects, birds and mammals -- need to move to stay within their preferred climate, the greater their chance of extinction.
The study suggests that scientists and governments should update habitat conservation strategies that have long emphasized drawing boundaries around environmentally sensitive areas and restricting development within those borders.
A more "dynamic" focus should be placed on establishing wildlife corridors and pathways linking fragmented habitats, said research co-author Healy Hamilton of the California Academy of Sciences.
"Things are on the move, faster than we anticipated," she told Reuters. "This rate of projected climate change is just about the same as a slow-motion meteorite in terms of the speed at which it's asking a species to respond."
The new research suggests that denizens of mountainous habitats will experience the slowest rates of climate change because they can track relatively large swings in temperature by moving just a short distance up or down slope.
Thus, mountainous landscapes "may effectively shelter many species into the next century," the scientists wrote in the study, which is to be published in Thursday's issue of the journal Nature.
This is especially crucial for plant species, which due to their being rooted in the ground cannot migrate at nearly the pace of animals in response to habitat changes.
Climate change will be felt most swiftly by inhabitants of largely flat landscapes, such as mangroves and prairie grasslands, where the rate of warming may more than double the quarter mile per year average calculated for ecosystems generally, the study found.
Nearly a third of the habitats studied in the report face climate change rates higher than even the most optimistic plant migration estimates.
Lowland deserts are likewise subject to a higher velocity of climate change, although the trend toward protecting large swaths of desert may ease the problem there.
By contrast, much of the world's forest habitats and grasslands already have been severely fragmented by development, making mitigation of climate change in those landscapes harder and leaving their species more vulnerable.
The velocities charted in the report were based on the "intermediate" level of projected greenhouse gas emissions assumed over the next century by the U.N.'s Intergovernmental Panel of Climate Change.
© Thomson Reuters 2009. All rights reserved.
The Telegraph (U.K.), Dec. 23, 2009
For species in flatter, low-lying regions such as deserts, grasslands, and coastal areas, the pace of the retreat could exceed more than half a mile a year, it is claimed.
Creatures and plants only able to tolerate a narrow range of temperatures will be most vulnerable, said the researchers.
Those unable to match the migration speeds needed to escape the effects of global warming could vanish into extinction.
Plants in almost a third of the habitats studied were thought to fall into this category, the scientists reported in the journal Nature.
Fragmentation by human development made the situation more perilous in some areas as it left many species with "nowhere to go".
The researchers combined data on climate and temperature variation worldwide with projections to calculate the "temperature velocity" for different habitats. This is a measure of how fast temperature zones are moving across the landscape as the planet warms - and how quickly plants and animals will need to migrate to keep up.
The expected temperature velocity for the whole of the 21st century was 0.26 miles per year.
Author Dr Chris Field, director of the Carnegie Institution's Department of Global Ecology in Stanford, California, said animals will be forced to migrate while many plants will die out.
"Expressed as velocities, climate-change projections connect directly to survival prospects for plants and animals. These are the conditions that will set the stage, whether species move or cope in place," he said.