UC Irvine researchers have linked an increased precipitation and fresh-water flow into oceans to global warming, according to a study released Monday.
Using NASA and other world-scale satellite observations, researchers tracked total monthly water volume flowing from land into the oceans and found an average annual increase of 1.5%.
"That might not sound like much… but after a few decades, it's huge," according to a statement from Jay Famiglietti, UC Irvine Earth system science professor and principal investigator on the study, which will be published this week in Proceedings of the National Academy of Sciences.
"In general, more water is good," Famiglietti continued. "But here's the problem: Not everybody is getting more rainfall, and those who are may not need it. What we're seeing is exactly what the Intergovernmental Panel on Climate Change predicted — that precipitation is increasing in the tropics and the Arctic Circle with heavier, more punishing storms. Meanwhile, hundreds of millions of people live in semiarid regions, and those are drying up."
The study is ongoing, but has so far found that at least 18% more water is being fed into Earth's oceans as of 2006 than when the study began in 1994.
This change is due to a shift in climate patterns where hotter temperatures are leading to more water evaporation and rain, thus leading to more fresh-water running from land to the ocean.
According to the study, the increase in water flow to the ocean creates a dangerous cycle that may escalate over time.
However, the researchers cautioned that although they had analyzed more than a decade of data, it was still a relatively short time frame. Natural ups and downs that appear in climate data make detecting long-term trends challenging.
Further study is needed and under way, they said.