As global temperatures continue to rise, droughts will become more frequent in many regions. Now a new study in the journal Nature has found that ecosystems are taking progressively longer to recover from droughts, and that incomplete drought recovery may become the new normal in some areas, possibly leading to tree death and increased emissions of greenhouse gases.
The paper was led by Dr. Christopher Schwalm of the Woods Hole Research Center. Using remote sensing, field data, and Earth system modeling, the researchers measured recovery time following droughts in various regions of the world.
“The most important implication of our study,” said Dr. Schwalm, “is that under business-as-usual emissions of greenhouse gases, time between drought events will likely become shorter than time needed for recovery.”
While the study noted that, “across many regions more frequent and severe droughts are expected in the 21st century,” the researchers found that drought recovery times in two regions of the climate system, the tropics and the northern high latitudes, were longer than in other regions.
The scientists argue that recovery time is a crucial “metric for assessing ecosystem resilience, as this time scale shapes the odds of crossing a ‘tipping point.’” A shorter time between droughts combined with longer recovery time means widespread tree mortality and potential widespread degradation of the land carbon sink.
“This work clearly highlights the need to obtain more detailed information on how the vascular system of trees will cope with future droughts,” said co-author Franco Biondi, professor of natural resources and environmental sciences in the College of Agriculture, Biotechnology and Natural Resources, University of Nevada, Reno.
NASA press release: www.jpl.nasa.gov/news/news.php?release=2017-217
Schwalm, C.R., W.R.L. Anderegg, A.M. Michalak, J.B. Fisher, F. Biondi, G. Koch, M. Litvak, K. Ogle, J.D. Shaw, A. Wolf, D.N. Huntzinger, K. Schaefer, R. Cook, Y. Wei, Y. Fang, D. Hayes, M. Huang, A. Jain, , and H. Tian. 2017. Global patterns of drought recovery. Nature. doi:10.1038/nature23021