Global warming is already causing irreversible damage to forest ecosystems around the globe
Adding to an ever-growing body of research that warns of impending global catastrophe due to climate change, two studies published back-to-back last week provide evidence that rising temperatures are affecting forests and vegetation across the globe, from Central Europe to the tropics. Worse still, these effects may be irreversible.
The first study, conducted by researchers at the University of Würzburg in Germany, found long-lasting effects of soaring temperatures on forests in Central Europe. The European drought of 2018—the most severe and long-lasting summer drought and heatwave ever recorded—saw temperatures of 3.3 degrees Celcius higher than the long term average. This “hotter drought” caused the most ecologically and economically important tree species in the forests of Austria, Germany, and Switzerland to show severe signs of stress. Moreover, unexpectedly strong “drought-legacy” effects of the drought were detected the following year, the study revealed.
“At such temperatures, our Central European vegetation reaches its limits,” said Bernhard Schuldt, head author of the study, in a summary published by the University of Würzburg. He cautions that this season’s heavy rains will not offset what has already been set in motion. Due to legacy effects, the affected trees in the region will continue to die off in the coming years.
There is an urgent need, he continued, for a pan-European ground-based monitoring network suited to track individual tree mortality, supported by remote sensing products with a high spatial and temporal resolution to track, analyze and forecast these transitions.
Perhaps more worrying is that these effects are not unique to Central Europe. A second study, conducted by researchers at the University of New South Wales, predicts that global warming may jeopardize a full one-half of the world’s tropical plant species within the next 50 years. The study suggests that by 2070, the temperature in the tropics would have exceeded the ideal conditions required for more than half the plants to germinate, and be too hot for one in five seeds to germinate at all.
Lead author of the paper, Alex Sentinella, said that it was previously assumed that since tropical plants came from a stable climate with consistently warm temperatures, they would be able to tolerate a narrower temperature range than species at higher latitudes. However, while these plants are indeed more threatened by rising temperatures, it is because they are already living at the higher end of their temperature limit.
“We know warming will affect species regardless of where they are, but we wanted to look at how much warming these species could cope with,” Sentinella told The Guardian.