How Rising Temperatures Threaten Tropical Forests: Signs of Doomsday on Forest Leaves

Editorial, CNBC Indonesia

Tech

Sunday, 01/10/2023 19:15 IWST

Foto: REUTERS/Joseph Campbell

Jakarta, CNBC Indonesia – Global warming followed by climate crises and disasters is a real threat of ‘doomsday’ that can destroy all life on earth. In fact, these signs are now starting to appear on the leaves in the forest.

Trees in forests are usually exposed to sunlight and absorb water with their roots. However, because the sun is too hot, the temperature is too hot, which can cause the photosynthesis process to stop.

Research by Gregory Goldsmith from Chapman University in California and his team found that several parts of tropical forests were approaching temperature limits, disrupting the photosynthesis process.

“Studies show that leaves in tropical forests at certain places and times have exceeded critical temperature limits,” said Goldsmith, quoted on Sunday (1/10/2023).

Trees in tropical forests can carry out photosynthesis at temperatures up to 46.7 degrees Celsius. But the researcher explains that the abilities of different species depend on the forest population, the number of leaves on the trees, and the canopy.

The Northern Arizona University team used Earth’s surface temperature data from NASA’s ECOSTRESS to find out which leaves in tropical forests were “so hot” that they couldn’t photosynthesize.

Data collected from satellite monitoring in the 2018-2020 period was then validated with surface sensors placed in the treetops of five forests in Brazil, Puerto Rico, Panama and Australia.

The analysis found that temperatures in the forest canopy peaked at 34 degrees Celsius in the dry season, although some leaves reached temperatures of 40 degrees Celsius. A small portion of leaves, namely 0.01 percent of the sample, exceeded the crisis temperature (46.7 degrees Celsius) at least once during the dry season.

“Even though it is still rare, extreme temperatures can have a catastrophic impact on leaf physiology. It can be classified as an extraordinary impact event with a low probability,” wrote the research report.

According to the ScienceAlert report, trees close the pores in their leaves, called stomata, to conserve water whenever the temperature gets too hot.

However, closing the stomata makes the leaves potentially damaged because they cannot “cool themselves” through the transpiration process. In dry periods, when the soil hardens, the impact of hot weather can be even more severe.

“Believe it or not, we don’t know much about why trees die,” Goldsmith said.

There is still very little scientific understanding of the effects of heat and drought, water and temperature, on plants.

Then, the research team used the data they had to run simulations to understand the response of tropical forests to rising temperatures and increasingly frequent droughts.

Simulations show that 1.4 percent of forest canopy shoots could stop photosynthesising in the future as a result of global warming. If global warming passes 3.9 degrees Celsius, entire forests could not survive. The leaves will dry and the trees throughout the forest will die one by one.

However, researchers emphasize that these calculations are only probabilities. It is possible that severe impacts occur at different temperatures. Therefore, it is very important to reduce emissions and prevent deforestation to protect tropical forests.

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