Climate researchers at Dartmouth College and from the Lamont-Doherty Earth Observatory of Columbia University, have posed questions to the touted role of plants in future climate change scenarios. Although plants help in reducing CO2 present in the atmosphere, the new study says that the abundance of CO2 will promote massive vegetation at a rate that will outpace the soil’s ability to replenish its water content.
Author of the study, Justin S. Mankin, a climate scientist at the Lamont-Doherty Earth Observatory and an Assistant Professor of Geography at Dartmouth, explained by likening plants to a straw that uptakes water from the soil. Since plants have an abundance of CO2 to acquire from the atmosphere during transpiration, plants are likely to grow massively. As a result,
Massive vegetation will become a massive determinant of how much fresh water will be available for human consumption”
The Dartmouth study used climate models in which future conditions will be longer and warmer; allowing plants to live longer and therefore consume much of the Earth’s water content. As a result, there will be less fresh water available for the human population, which in the future will also increase in numbers.
Three Key Plant Interactions that Would Impact Water Availability
This new study reveals findings that project potential plant responses, which will make the land drier instead of wetter, and therefore impose a massive impact on millions of people.
Inasmuch as 60 percent (60%) of the global water flux occurs by way of plant transpiration, plants will not need to release a lot of water during the process; making plants more efficient with water usage
Even if water is additionally supplied by way of rainfall, the Dartmouth scientists pointed out that plant interactions during warmer conditions and increased CO2 in the atmosphere, can impact the amount of water that will be available in the soil.
In future climate conditions where there are higher levels of CO2 in the atmosphere, plants do not have to release much water through its leaves in order to get the amount of CO2 they need for photosynthesis. If plants release less water, it means they will retain much of the water absorbed by their roots.
As the planet continues to warm, plants will have a longer time and better chances to grow extensively. Therefore more will cover the land and consume greater amounts of water.
As vegetation becomes more abundant, more plant roots will absorb water and leave less in the soils and streams.
The Dartmouth-led study points out that such interactions will impact regions where there is a disconnection between precipitation and the population’s demand, or usage of water. The scientists cited California as an example, since more than half of the region’s precipitation occurs only during winter, whilst needing to contend with peak demands during summer. In order to meet the demand with supply, solutions have been engineered to move water from Point A to Point B.
Professor Mankin said that in light of their findings,
“We cannot expect plants to be a universal panacea for future water availability. “It is a must therefore to assess with clarity, why and where there is a need to anticipate potential changes in water availability as those will prove crucial in preparing for the future.