Scientists from the United States have linked – in a new scientific study – the high level of carbon in the Earth’s atmosphere, with the increase in the frequency of floods in the country.
But the new effect factor revealed by the researchers is not expected, as the results of the study they conducted showed that plants absorb less water in the new conditions, which increased the amount of water that reaches rivers and lakes.
Floods are on the rise
Many regions of the world are witnessing an increasing number of floods resulting from high levels of rivers, the most recent of which occurred recently in Sudan and led to tens of deaths and the displacement of hundreds of thousands, due to the flood of the White Nile, which rose to a record level unprecedented in modern history.
The increase in the frequency of floods is usually attributed to the disturbances caused by the phenomenon of global warming on the main factors of the climate such as temperature and humidity. However, no study has previously dealt with the factor that reduces the ability of plants to absorb water in the high level of rivers in the world.
In the new study published in the October issue of the Journal of the Geological Society of America (GSA Today), University of Oregon scientists compared historical data for the concentration of carbon dioxide in the atmosphere with that of leaf samples, to determine the relationship between height Carbon levels and catastrophic flooding mounting in the American Midwest.
Plants that absorb less water
Using data covering more than two centuries, the researchers showed that as carbon levels in the atmosphere rose due to the combustion of fossil fuels, the ability of plants to absorb water from the air decreased.
This means that more rain works its way into rivers and streams, increasing their ability to cause flood damage.
For this purpose, the team examined the leaf pores of the ginkgo biloba tree, which are small holes that deciduous (or deciduous) trees use to absorb carbon dioxide from the atmosphere.
Scientists had previously noticed that the pore density in the leaves of these plants increased in low-carbon environments, so that they could absorb enough carbon dioxide for use in the photosynthesis process, but in carbon-rich environments this process requires fewer stomata.
These stomata play an important role in regulating the process of plant absorption of water and the release of water vapor (or transpiration). The smaller the number of pores, the lower the potential for transpiration. The researchers found that the density of stomata in the leaf samples they examined decreased overall by about 29% between 1829 and 2015.
The researchers also noted that this decrease directly affected the devastating floods that are increasingly occurring in the United States, and they emphasized that the humidity caused by the decrease in absorption in plants affects the level of rivers due to the increase in the amount of water in them, which means that the droplets that are no longer absorbed by the plants may transform To floods!
What about recent Sudan floods?
While this study proves the relationship between the increase in the concentration of carbon in the atmosphere with the changes that occurred in the increase in the floods of the Mississippi River and the decline in the ability of plants that grow around it to absorb water, it is questionable to ask whether this relationship had a role in what happened recently in Sudan of floods and a record high in the river level Nile?
“It is known that high carbon dioxide levels lead to an increase in air temperature, which in turn increases the frequency of droughts and floods due to the disruption of the natural water cycle,” said Dr. Jawad al-Kharraz, a water expert at the Middle East Desalination Research Center, in an interview with Al-Jazeera Net.
Al-Kharraz added, “It is not believed that the decrease in the ability of plants to absorb water is a decisive factor in increasing the frequency of floods, although they have a relative impact as the study indicates.”
Concerning the Sudan floods and the role of the factor referred to in the new study, the Moroccan researcher emphasized that “the heavy rains that fell in a short time, along with the fragility of the infrastructure, are the two main reasons for what happened. A field study should be carried out to confirm or deny the role of any additional factor in what happened.” “.
The authors of the new study hope that their findings will contribute to demonstrating the threat that climate change and associated floods pose to farming communities and protect them from it.