A new study by climate scientists suggests some “hot spot regions” around the world contain ecosystems that are at-risk due to water availability.

A group of researchers from Germany, the Netherlands, and Australia investigated how changes in water and energy availability -- both crucial to the process of photosynthesis -- are projected to change around the world using a simulator, looking at 1980 to 2100.

Their findings, published in the journal Nature Climate Change on Monday, suggest ecosystems in Central Europe, the Amazon, and Western Russia are going to be impacted as climate change limits water availability.

Energy, including sunlight and heat, is not in short supply as climate change increases energy availability for plants and ecosystems. But Jasper Denissen, a former PhD student at the Max Planck Institute for Biogeochemistry in Germany and the lead author of the study, says water availability is another story.

“We found that globally, ecosystems become thirstier by becoming more water-limited,” Denissen said in a press release.

The simulator suggests an additional six million square kilometres of the Earth’s land surface could become water-limited by 2100, compared to 1980.

Periods of water limitation are also projected to increase in duration, according to the study, with nearly half the study area experiencing water shortages for two months longer per year by 2100.

"These shifts in the vegetation's water limitation in space and time leave vegetation craving for water across larger regions and during longer consecutive periods," said Rene Orth, another lead author of the study, in the release.

The researchers say the information is crucial, as well-functioning ecosystems and the process of photosynthesis play key roles on our planet, including providing food and water security, intaking carbon dioxide created by human activity, and providing evaporative cooling to bring temperatures down.

Evaporative cooling occurs during photosynthesis when small openings on the leaf of a plant, called stomata, open up to take in carbon dioxide, according to the study. Through the open stomata, water from the plant evaporates back into the atmosphere. This process creates a cooling effect, which researchers say is crucial in dealing with rising temperatures and extreme heat waves due to climate change, possibly preventing heat stress and heat-related deaths.

The study’s authors say more research is needed to understand how ecosystems are impacted by climate change to make changes to human activity, including agriculture and forest management, to mitigate the impact on ecosystems.