Rising Temperatures Linked to Extensive Leaf Mortality in Tropical Forests.

Graph of the Day: Locations of Forest Mortality Related to Climate Stress from Drought and High Temperatures.

August 26, 2023


A recent study published in the Nature journal on August 23 highlights new dangers posed by climate change to tropical forests. The study suggests that rising temperatures could lead to a phenomenon known as “mass leaf death,” where the leaves of tropical trees die or cease photosynthesis due to extreme heat. Even small temperature changes brought on by climate change could significantly impact plant species.

The study found that some tropical regions have experienced an average temperature increase of 0.5 degrees Celsius per decade. If individual leaf temperatures surpass a critical threshold (around 46.7 degrees Celsius), photosynthesis stops, and leaves may die if the exposure to such temperatures is prolonged. The study warns that prolonged heat exposure could lead to the collapse of tropical forests.


What is the main danger posed by climate change to tropical trees, according to the study?

The study suggests that rising temperatures due to climate change could lead to “mass leaf death,” where leaves die or stop photosynthesis due to extreme heat.

How do small temperature changes impact plant species in tropical forests?

Even small temperature changes brought on by the warming planet can have significant impacts on plant species, affecting their normal functioning.

What is the impact of the El Nino climate pattern on tropical forests?

The study notes that weather phenomena like the El Nino climate pattern are becoming more pronounced, contributing to changes in tropical forest conditions.

What is the critical temperature threshold for individual leaf temperatures that leads to photosynthesis cessation and potential leaf death?

The study suggests that if individual leaf temperatures increase beyond 46.7 degrees Celsius, photosynthesis stops, and leaves may die if exposed to such temperatures for prolonged periods.

How does the study link the potential collapse of tropical forests to specific climate scenarios?

The study states that if global temperatures increase by 3.9 degrees Celsius, tropical forests may undergo mass leaf damage, which could result in collapse. This scenario is particularly relevant if no actions are taken to mitigate climate change impacts, as per RCP 8.5 scenario.

What are the uncertainties surrounding the potential effects of heat exposure on trees?

While trees may use non-structural carbohydrate reserves to revive leaves, uncertainties exist regarding whether trees could regrow leaves effectively or die due to heat exposure’s long-term impacts.

How does deforestation and forest fragmentation contribute to the situation?

The study warns that deforestation and forest fragmentation can increase or destabilize local temperatures, exacerbating the effects of climate change and pushing already hot tropical regions towards critical thermal thresholds.

What temperature range has been identified as contributing to leaf death?

The study shows that a temperature range between 2 and 8.1 degrees Celsius, with 2 being the lowest and 8.1 being the highest, can result in leaf death.

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