Rainforest at biosphere 2 offers glimpse into future of the Amazon:
Tropical forests may be more resilient to predicted temperature increases under global climate change than previously thought, a study published in the journal Nature Plants suggests. The results could help make climate prediction models more accurate, according to the authors—an international team led by scientists in the University of Arizona Department of Ecology and Evolutionary Biology.
The group studied data from the rainforest habitat at UArizona's Biosphere 2 and compared them to measurements taken at natural tropical forest sites. Due to being encased under a glass dome, the tropical forest at Biosphere 2 is possibly the hottest tropical forest in the world, with temperatures reaching up to 40 degrees Celsius[104 F], about 6 C[10 F] higher than maximum temperatures currently experienced by natural tropical forests and in the range of what scientists expect them to experience in the year 2100, absent major climate change mitigation.
At Biosphere 2, when the effects of warming and drying were separated, the authors observed that, just as in natural forests, photosynthesis declined as the air dried, but when the air was wet, the trees continued to photosynthesize steadily at ever higher temperatures, right up to a forest-roasting 38 C[100 F].
"No previous studies of tropical forests looked at changes in temperature much beyond to what they experience today," said Scott Saleska, a professor in the UArizona Department of Ecology and Evolutionary Biology and senior author of the paper. "Biosphere 2 gave us a unique opportunity to look at what might happen when these forests get the full global warming treatment."
The maintenance of relative humidity in the forests appears to be the key to rainforest resilience to higher temperatures.
Journal Reference:
Marielle N. Smith, Tyeen C. Taylor, Joost van Haren, et al. Empirical evidence for resilience of tropical forest photosynthesis in a warmer world, Nature Plants (DOI: 10.1038/s41477-020-00780-2)
(Score: 4, Insightful) by PinkyGigglebrain on Wednesday October 14 2020, @08:11AM (2 children)
I thought the biggest threat to the rain forests wasn't increased temperature but Humanity's slash and burn tactics.
That a rain forest can handle higher heat as long as the humidity is within it's preferred range should not be much of a surprise to anyone.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 0) by Anonymous Coward on Wednesday October 14 2020, @01:55PM
It's the acidity that will kill us and the plants... Tropical areas might be uninhabitably hot before the acidification of the hydrosphere kills off at least the bulk of humanity, but the body count won't come close.
(Score: 0) by Anonymous Coward on Thursday October 15 2020, @01:27AM
At high temperature and high humidity, we and a lot of other animals that use evaporation to cool are going to be in trouble. Not sure what the upper limit is, but guess it wouldn't much higher than 100F.
Also, some tropical plants die at 100F (37.75C). I've been trying to grow mangosteen (from Indonesia), in California, without good enough environmental control (yet)-- this tree dies if temp drops below 50F (10C) or rises above 100F. I currently have to move the 15gal pots around between shade house, hot house, and into *the* house to keep them alive-- and only just barely succeeding (they are not thriving).