Wetenschap - 27 september 2011
Alterra looks for signs of decline of rainforest
Alterra is developing an early warning system for ecosystems in the Amazon region. Picking up the right signals should help to prevent the decline of the rainforest.
Vast
Knowledge about the tropical rainforests is limited. 'We have been doing research in the Amazon region for years. But we don’t know, for example, how the forests will react to a rise in CO2 concentrations or in temperature, brought about by climate change’, says project leader Bart Kruijt of Alterra. ‘Even with what we do know, no extensive runs have been done of climate models. The region is so gigantically vast, too. You are always running simulations based on limited knowledge.’
Savannah
Earlier studies suggest that rainforest can turn into savannah through climate change and deforestation. But whether it will come to this, where it will start, and what the first signs are, is not clear. Amazalert is expected to provide answers to these questions, partly by developing new, improved models. Kruijt: ‘What we really want is to link together a group of interconnected models so that we can also take into account the effects of policy and people’s response.’
Signals
According to Kruijt, there is a need for a better understanding of the feedback mechanisms between climate and changes on the land surface. Rainwater is constantly recycled via forests, through evaporation. Continuous deforestation puts this mechanism at risk. Scientists from the VU university in Amsterdam are trying to find out how this process works and whether there are any early signals which indicate a transition from forest to savannah.
Measurable
The early warning system that Alterra is developing should provide a set of measurable variables which show when things are going wrong in the Amazon. ‘Forest surface, for example, or river discharge or patterns of precipitation. These are hypotheses we want to test. But of course other factors might surface as well.’