Yahoo News 23 Dec 09;
PARIS (AFP) – Land ecosystems will have to move hundreds of metres each year in order to cope with global warming, according to a letter published on Thursday in Nature, the British-based science journal.
On average, ecosystems will need to shift 420 metres (about a quarter of a mile) per year to cooler areas this century if the species that inhabit them are to keep within their comfort zones, scientists in the US believe.
Flat ecosystems such as mangroves, wetlands and deserts face the biggest challenge, for they will have to move the farthest in order to survive.
Mountainous habitats are a bit luckier, as just a small shift in altitude provides some cooling.
The figures are based on the "A1B" scenario for likely carbon emissions this century, as forecast by the Intergovernmental Panel on Climate Change (IPCC). It is considered an intermediate level of warming.
Climate change would impact slowest in tropical and subtropical coniferous forests, temperate coniferous forests, so-called montane grasslands and shrublands, say the scientists.
Deserts, mangroves, grasslands and savannas would be hit fastest.
The paper suggests a ruthless Darwinian struggle will be unleashed.
Some rugged species may be able to adapt to warmer temperatures and modification of their home. Others that can migrate elsewhere in time will also survive.
But those species that cannot adapt -- or which move only slowly, such as plants -- will have nowhere to go and could face extinction.
"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," said co-author Chris Field, director of the Carnegie Institution?s Department of Global Ecology.
The study says that protected areas such as nature reserves are generally too small to cope with the expected habitat shifts.
Less than 10 percent of protected areas globally will maintain current climate conditions within their boundaries a century from now, it warns.
Under the A1B scenario, the best estimate of a UN's Nobel-winning panel of climate scientists foresees a temperature rise this century of 2.8 degrees Celsius (5.04 degrees Fahrenheit), in a range of 1.7-4.4 C (3.06-7.2 F).
A group of world leaders, at the Copenhagen climate summit last Friday, set the goal of limiting warming to 2 C (3.6 F), but did not explicitly say whether the benchmark was since industrial times or over the course of this century.
There has already been around 0.7 C (1.26 F) of warming since the start of the Industrial Revolution of the mid-18th century, when the burning of coal, oil and gas began the greenhouse-gas phenomenon.
Ecosystems strain to keep pace with climate
Steve Gorman, Reuters 23 Dec 09;
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.
(Editing by Mary Milliken and Bill Trott)
