An experiment in the Amazon forest will test a hypothesis that higher levels of CO2, due to climate change, can avert the drought and high temperatures it was supposed to cause.
SAO PAULO — Will global warming provide a solution to one of the problems it creates? To find an answer to this intriguing question, a team of scientists started taking measurements last week for what may be the most ambitious experiment the Amazon forest has seen in some 20 years. Ecologists are hoping the project, called Amazon FACE (Free-Air CO2 Enrichment), can tell them whether the forest will survive the drought that global warming is expected to cause.
Led by the Sao Paulo State University and bringing together more than 14 research centers, the experiment consists of permanently bombarding small parts of the forest with CO2. Some believe that higher concentration levels of carbon dioxide can boost photosynthesis, which would compensate for the forest's growth deficit, and even its feared death in case of drought.
"The simulated models show that the fertilizing effect of CO2 could be crucial in keeping the forest alive," explains ecology researcher David Lapola, leader of the experiment. "But for now this is still mere speculation. Only such an experiment will give us an answer."
The Amazon FACE is the first experiment of its kind in a tropical ecosystem. The first phase will take place from 2015 to 2017, and once fully set up, the project will last until 2027.
For that, scientists need to build a "gas ring" around the portion of forest they want to test, with high tube towers connected to a a CO2 tank. During the experiment, the concentration of carbon dioxide will be 200 parts per million over natural levels, a 50% increase of current measurements. The production of CO2 alone represents 62% of the experiment's total cost.
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A FACE facility in Nevada — Photo: U.S. Department of Energy
The location, 60 kilometers north of the town of Manaus, is well-known to scientists, as it has already been used in previous projects. It provides them with important data that has been collected since 1996, which will enable them to better measure the impact of CO2 in the trees' growth during the experiment.
To know if CO2 fertilization will counter the effects of droughts and higher temperatures, they will however need to feed their simulation models, so as to compare different effects expected from global warming.
"If we're lucky", there could be a drought period during the experiment, which would allow us to compare different situations," says Richard Norby from the U.S."s Oak Ridge National Laboratory, who will take part in the experiment.
One of the project's architects, climatologist Carlos Nobre, National Secretary for research and development policies at the Ministry of Science, Technology and Innovation, defends Amazon FACE as evidence of Brazil's scientific maturity. "We initiated the project and looked for international collaborators from the best institutions who have experience in these types of environments," he explained.