A stronger role for long-term moisture change than for CO₂ in determining tropical woody vegetation change

The influence of long-term fluctuations in atmospheric carbon dioxide (CO2) on woody vegetation growth is complex. The prevailing paradigm has been that it enhances growth. However, using a 500,000-year record of vegetation change at a site in tropical Africa, Gosling et al. conclude that shifts in atmospheric CO2 concentrations do not drive changes in woody cover in the tropics at the millennial scale. Instead, long-term changes in moisture appear to have a greater effect. In the context of current climate change and increasing CO2 concentrations, these findings suggest, at least for the tropics, that models and policies for anthropogenic climate change mitigation involving enhanced CO2 drawdown into vegetation may not be as effective as hoped. —AMS