Southwest America Most Likely to Suffer from Megadrought as Average Temperature Rises
A new study revealed that there is 20 to 50 percent chance of megadrought, one that lasts more than 35 years, occurring in Southwest America in this century.
The study, published in the journal Science Advances, showed that the warming temperature of Earth due to human-induced climate change is increasing the probability of megadroughts. Furthermore, a four degrees Celsius increase in average regional temperature could make megadroughts 70 to 99 percent more likely.
"The increase in risk is not due to any particular change in the dynamic circulation of the atmosphere," said Toby Ault, a professor of earth and atmospheric science at Cornell University and lead author of the study, in a press release. It's because the projected increase in atmospheric demand for moisture from the land surface will shift the soil moisture balance. If this happens, megadroughts will be far more likely for the next millennium."
The surface moisture balance of forest is being governed by a natural tug-of-war between the precipitation supply and evaporation. As the regional average temperature increases the odds of winning bend toward evaporation, drying out the land surface and leads to the occurrence of megadroughts.
However, Ault noted that there is some good news in their findings. They found that the occurrence of megadroughts is highly dependent on temperature, suggesting that the probability of it happening can be greatly reduce if the regional average temperature does not go beyond about 2 degrees Celsius.
Furthermore, an aggressive strategy to cut greenhouse gas emissions could also prevent megadroughts from occurring. However, researchers warned that despite human's best effort, megadroughts risks are still likely in the future. Therefore, the researchers advised people living in the Southwest to efficiently use their water resources, especially in drought-stricken areas. Doing so could help people in the region to thrive despite the harsh consequences of climate change.