Tropical Forests Are Heating—Can They Cope?
By Madeleine Seale et al, Science.
Excerpt: Perhaps the biggest challenge confronting plants will be in the tropics, where temperatures are already high—and are projected to rise as much as 4°C by the end of the century if more isn’t done to curb climate change. “They’re the hottest forests,” says ecologist Kenneth Feeley of the University of Miami. “So, the question is: What happens when we go into unprecedented heat?” ...Some tree species in Mexico, for example, have shifted to higher elevations, where temperatures are cooler, a recent paper in Science reported). But across the Americas, tropical species aren’t moving fast enough to keep pace with warming, and researchers are skeptical that they will be able to cope by migrating upslope or away from the equator. Nor is evolution likely to be the answer. Trees can take decades to start reproducing, making it unlikely they can evolve new genetic adaptations for heat tolerance fast enough to withstand rising temperatures. ...Plants do have ways to cope with heat stress, however .... Increasing the production of isoprene, a volatile organic chemical found in many plants, for example, can protect cells against reactive oxygen molecules. Plants can also tune their photosynthetic machinery to perform better at higher temperatures....