Climate change could be devastating ecosystems and economies in the tropics within a generation, scientists have predicted.
Researchers showed that current levels of greenhouse gas emissions would lead to a transformation of climate around the world as early as 2047. But in the most vulnerable regions the impact could be felt much sooner.
Areas within the tropics could be experiencing unprecedented changes in temperature and rainfall in as little as two decades.
The effect on sensitive tropical ecosystems could be catastrophic, it is claimed, with species being forced to move, rapidly adapt, or face extinction.
Since the tropics house most of the world’s population and contribute significantly to global food supplies, the social and economic impact would also be serious and far-reaching.
“The results shocked us,” said lead researcher Camilo Mora, from the University of Hawaii.
“Regardless of the scenario, changes will be coming soon.
“Within my generation, whatever climate we were used to will be a thing of the past.”
The scientists used 39 climate simulation models to look at the likely effects of global warming in different locations around the world.
They used the minimum and maximum temperatures from 1860 to 2005 to define the historic bounds of climate variability in each region.
Projections over the next 100 years showed when the climate in any given location was expected to shift outside these limits.
The critical turning point was defined as the “year of climate departure”.
Under a “business-as-usual” scenario in which greenhouse gas emissions continued to rise at their present rate, the average region on earth was predicted to experience a radically different climate by 2047.
An alternative scenario that assumed greenhouse gas stabilisation forecast a global average “climate departure” in 2069.
But the tropics, which are especially vulnerable to small changes in climate, were forecast to cross the climate departure point a decade earlier than anywhere else on earth.
They also happen to be the poorest regions on earth and those least able to cope with the effects of climate change, the researchers pointed out.
“Our results suggest that countries first impacted by unprecedented climates are the ones with the least capacity to respond,” said co-author Ryan Longman, also from the University of Hawaii.
“Ironically, these are the countries that are least responsible for climate change in the first place.”
Commenting on the findings, published in the journal Nature, US expert Ken Caldeira from the Carnegie Institution for Science in Washington DC said: “This work demonstrates that we are pushing the ecosystems of the world out of the environment in which they evolved into wholly new conditions that they may not be able to cope with,” he said.
“Extinctions are likely to result. Some ecosystems may be able to adapt, but for others, such as coral reefs, complete loss of not only individual species but their entire integrity is likely.”
The data is displayed on an interactive map aimed at helping people understand the likely progression of climate change where they live, and increasing awareness about the problem.
Mora added: “Scientists have repeatedly warned about climate change and its likely effects on biodiversity and people.
“Our study shows that such changes are already upon us. These results should not be reason to give up.
“Rather, they should encourage us to reduce emissions and slow the rate of climate change.”