Research: rising carbon levels increase flood risk

Scientists from the United States have linked the level of carbon in the Earth’s atmosphere to the number of floods in the country. According to them, in new conditions, plants absorb less and less water and it gets into rivers and lakes.

In a new study, scientists from the Geological Society of America compared historical data on atmospheric carbon with observations of river levels. The researchers showed that as carbon levels increased, the plants’ ability to absorb water decreased. This means more rainfall flows into rivers and lakes – this increases the risk of future flooding.

The team examined leaf stomata – tiny pores that deciduous plants use to absorb carbon dioxide from the atmosphere. In a low-carbon environment, plants increase stomatal density so they can take up enough carbon dioxide for photosynthesis, but in carbon-rich environments, they require fewer stomata.

The stomata also regulate transpiration, the process by which plants absorb water and release water vapor; the fewer there are, the lower the transpiration potential. In the studied leaf samples, scientists observed a general decrease in stomatal density. In their opinion, this figure has decreased by 29% over the past 260 years.

The authors note that this decline directly influenced the devastating floods that are increasingly occurring in the United States. They are confident that less absorbed moisture affects the level of rivers due to increased water runoff.

“Increasing carbon levels are not always factored into flood forecasting and risk analysis,” the researchers noted. “We hope that our work will help show the danger that climate change and the associated flooding pose to agricultural communities across the United States.”