March 13th, 2013 by Joshua S Hill
Understanding the planet’s reaction to global warming is an important step in predicting what we might expect to face in the coming decades, and a new recently published study has found that tropical forests are more resilient to global warming than previously understood.
The study, published in the journal Nature Geoscience, is the most comprehensive assessment of the risk the tropical forest faces due to climate change.
The study provides programmes such as the United Nation’s Reducing Emissions from Deforestation and Degradation+ scheme an understanding of the future of tropical forests so they can better tailor their methods to the reality of the situation.
Furthermore, studies like this provide invaluable climate data to computer models looking at the future of our planet’s climate, refining the results to create more accurate results.
The international team of climate scientists and tropical ecologists from the UK, USA, Australia, and Brazil used computer simulations with 22 climate models to see how tropical rainforests in the Americas, Africa, and Asia would respond to greenhouse-gas-induced climate change.
The results were surprising, as the only tropical forest in the simulations to lose biomass — plants and plant material — was in the Americas and it only happened in one of the models. The researchers found the largest source of uncertainty in the climate projections coming from how plant physiological processes are represented, choice of emission scenario, and differences between various climate projections.
“The big surprise in our analysis is that uncertainties in ecological models of the rainforest are significantly larger than uncertainties from differences in climate projections,” said lead author Dr Chris Huntingford from the Centre for Ecology & Hydrology in the UK. “Despite this we conclude that based on current knowledge of expected climate change and ecological response, there is evidence of forest resilience for the Americas (Amazonia and Central America), Africa and Asia.”
The work does suggest that the risk of climate-induced damage to tropical forests will be minimal, the paper is certain to make clear where considerable uncertainties remain in understanding how ecosystems will respond and are responding to global warming.
“This study highlights why we must improve our understanding of how tropical forests respond to increasing temperature and drought,” explained Dr David Galbraith, a co-author from the University of Leeds.
“Different vegetation models currently simulate remarkable variability in forest sensitivity to climate change. And while these new results suggest that tropical forests may be quite resilient to warming, it is important also to remember that other factors not included in this study, such as fire and deforestation, will also affect the carbon stored in tropical forests. Their impacts are also difficult to simulate. It is therefore critical that modelling studies are accompanied by further comprehensive forest observations.”
“This study is probably the most comprehensive modelling study thus far exploring the effects of climate change on tropical forest viability, involving a large number of climate modellers, plant physiologists and tropical forest scientists,” added Professor Yadvinder Malhi of the University of Oxford. “It considers a large number of climate models, several vegetation simulation models, a range of physiological physiological processes, and tropical forests world-wide. It finds that, to the best of our knowledge, it is very unlikely that climate change on its own will cause large scale loss of tropical forests.”
Dr Lina Mercado, of the University of Exeter and CEH, added that, building on the study, “one of the big challenges that remains is to include, in Earth system models, a full representation of thermal acclimation and adaptation of the rainforest to warming.“
Previous research has found that deforestation in tropical forests can have a significant effect on tropical rainfall:
A team from the University of Leeds and the NERC Centre for Ecology & Hydrology found that for the majority of the Earth’s tropical land surface, air passing over extensive forests produces at least twice as much rain as air passing over little vegetation. In some cases these forests increased rainfall thousands of kilometres away.
By combining observational data with predictions of future deforestation, the researchers estimate that destruction of tropical forests would reduce rain across the Amazon basin by up to a fifth (21 per cent) in the dry season by 2050.
Furthermore, research from 2011 looked at what happened when lack of rainfall and climate change does enough damage to a tropical area. The research showed that the change from tropical forest to savannah would be a relative quick transition.
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