Falmouth, Mass. – A new paper published in Global Change Biology co-authored by Woods Hole Research Center scientist, Michael Coe draws upon three environmental models to simulate the combined impacts of climate change, rising carbon dioxide levels, land-use change and fire on Amazonian forests up to the year 2100. These simulations ultimately highlight the catastrophic implications of unregulated development driving land-use change in the Amazon.
Rising levels of CO2 in the atmosphere will most certainly affect vegetation. In fact, studies of the temperate forests in the mid-latitudes reveal that more CO2 leads to more robust growth and forests that are less sensitive to the drought that accompanies climate change. This study simulated the response of tropical Amazonian forests to increasing atmospheric CO2 and found forests expanding in the same way, despite the accompanying climate-induced water stress. Further complicating the results were the wide ranging estimates of forest loss when fire and land-use change were factored in the calculations along with CO2 fertilization and climate change. All of these calculations were based on the assumption that tropical forests will respond positively to greater CO2 concentrations in the atmosphere, however, there is no certainty that that will be the case.
For Dr. Coe, “If Amazonian forests don’t respond positively to increasing CO2 then forest die-back from climate change could be extensive -more than 30% of Amazonian forests disappear in some of our simulations.” With this level of variability, Dr. Coe suggests that the most important factor in determining the future of Amazonian forest extent is the continuing enforcement of regulations aimed at reducing deforestation in Brazil.
The model simulations used in this study incorporate future deforestation scenarios based on preservation of current protected areas and enforcement of Brazil’s Forest Code which protects 80% of forests on private lands. This study implies that even if current deforestation targets were achieved, land-use impacts could exceed any potential forest cover expansion arising from either CO2 fertilization or a more favorable future climate. Much is still unknown and these simulations highlight the catastrophic implications of unregulated development driving land-use change in the Amazon.
WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.