Global Warming to Create Novel Climates

Global Warming to Create Novel Climates



March 2007 - Many current climate 
zones will vanish entirely by the year 2100, replaced by 
climates unknown today, according to new global warming 
research. The greatest changes are predicted for Amazonian and 
Indonesian rainforests, but areas such as the southeastern and 
western United States, northwestern Australia, and the Arabian 
Peninsula also would be affected. 
Tropical and subtropical regions would experience new climates 
if current global warming trends continue, found University of 
Wyoming Professor Steve Jackson and his colleagues at the 
University of Wisconsin. The scientists assessed the risk of 
novel and disappearing climates during the next 100 years. 

University of Wyoming botany professor Steve Jackson 
"The frightening thing about our analysis is that it shows 
that climate change will take us into uncharted waters," says 
Jackson, a professor in the University of Wyoming Department 
of Botany who specializes in the ecological consequences of 
climate change. 
Jackson conducted the study with University of Wisconsin 
professor of atmospheric and oceanic sciences John Kutzbach 
and geographer Jack Williams. 
The scientists used climate models and greenhouse gas emission 
scenarios from the most recent assessment by the 
Intergovernmental Panel on Climate Change released in 
February. 
They found that under both the high-end and low-end emissions 
scenarios, many regions would experience climate changes large 
enough to drive major ecological transformations - pine forest 
would turn into grassland, or rainforest would become savanna. 

Williams likens today's environmental analysts to 15th century 
European mapmakers confronted with the New World, struggling 
to chart unknown territory. 
"We want to identify the regions of the world where climate 
change will result in climates unlike any today," Williams 
says. "These are the areas beyond our map." 
"In a few decades, climates in many areas will be unlike any 
in our current experience," Jackson said. "That poses huge 
challenges for predicting economic, agricultural, and 
ecological consequences." 
Wyoming grasslands would be at greater risk of droughts if 
climate change continues. 
He says that under the high-end scenario, the entire American 
West, including Wyoming, will experience climate changes of 
sufficient magnitude to disrupt existing ecological 
communities. 
"The entire region is projected to experience higher 
temperatures in both summer and winter, drier in the summer, 
and wetter in the winter," Jackson says. "The higher 
temperatures and drier summers could increase Wyoming's risk 
of drought and wildfires." 
Changes will occur so quickly that it will be difficult to 
prepare for them, he says. 
"This work helps highlight the significance of changes in the 
tropics," complementing the extensive attention already 
focused on the Arctic, said Kutzbach. "There has been so much 
emphasis on high latitudes because the absolute temperature 
changes are larger." 
However, Kutzbach explains, normal seasonal fluctuations in 
temperature and rainfall are smaller in the tropics, and even 
"small absolute changes may be large relative to normal 
variability." 
"The rapid rate of change will be disruptive. Some changes may 
be beneficial in some places. For example, there could be more 
water available in some areas," Jackson says. "But many of the 
changes will be unpleasant and disruptive. Most ecosystems 
aren't geared to adapt to rapid changes of this magnitude." 
Tropical mountains and near polar regions such as the Peruvian 
and Colombian Andes, Siberia, South Africa, and southern 
Australia face a risk that their existing climates will 
disappear altogether. 
The Amazon rainforest, already imperiled by logging and land 
clearing for agriculture and ranching, would be completely 
changed if global warming continues. 
The researchers found that existing climates will disappear 
from as much as 48 percent of the terrestrial globe; novel 
climates will develop in up to 39 percent of the Earth's land 
mass, and these changes are generally concentrated in the 
tropics - the places of highest biodiversity and ecosystem 
complexity. 
Many regions facing the disappearance of their existing 
climates have been identified as biodiversity hotspots, 
suggesting that standard conservation solutions may fail to 
protect biodiversity in these areas. 
"Many species will have no place to go," Jackson says. 
Physical restrictions on species may also amplify the effects 
of local climate changes. The more relevant question, Williams 
says, becomes not just whether a given climate still exists, 
but "will a species be able to keep up with its climatic zone? 
Most species can't migrate around the world." 
The work was funded by the National Science Foundation and the 
findings were published Monday in the "Proceedings of the 
National Academy of Sciences." 
The new study confirms findings published in March 2006 by the 
global conservation organization WWF, which asserted that 
"climate change and deforestation could convert the majority 
of the Amazon rainforest into savannah, with massive impacts 
on the world's biodiversity and climate." 
"Such changes would result in significant shifts in ecosystem 
types - from tropical forest to dry savannah - and loss of 
species in many parts of the Amazon," WWF said. 
"A changing climate poses a substantial threat to the Amazon 
forests, which contain a large portion of the world's 
biodiversity," said Beatrix Richards, forests expert at WWF. 
"Threats here translate into threats to biodiversity at large. 
The world needs to urgently evaluate vulnerability to climate 
risks and integrate them into biodiversity conservation 
efforts." 





 

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