The study, conducted jointly by specialists from the Grassland Research Institute of the Chinese Academy of Agricultural Sciences and scientists from the United States, focused on analyzing data regarding the content of carbon dioxide and water vapor in the atmosphere over a period of 34 years.

The study found that the rate of growth of photosynthesis in plants slowed down significantly. This contradicts previous ideas that increasing atmospheric carbon dioxide levels should stimulate photosynthesis and therefore plant growth.

Scientists have concluded that the reason for the slowdown in photosynthesis is an increase in the vapor pressure deficit in the atmosphere. This leads to more intense evaporation of water from plants, which, in turn, stimulates the closure of stomata – small holes on the surface of leaves through which gas exchange and evaporation occur. Closing stomata is necessary for plants to conserve moisture, but it also interferes with photosynthesis as it limits access to carbon dioxide, Phys reports.

The researchers used data collected by ground monitors around the world, as well as information obtained from satellite imagery, to analyze changes in the planet’s green regions. In addition, they have resorted to the help of artificial intelligence to detect even subtle changes that are difficult to notice using human perception. Machine learning methods were used to identify the relationship between foliage color and photosynthetic rate.

Forecasts based on the study predict that the atmosphere will become increasingly warmer and drier in the coming years. This will further reduce the rate of photosynthesis in plants, despite rising carbon dioxide levels.