14 DAY TRIAL // Weather experts have predicted years ago that more water will move from the soil to the atmosphere with global warming, and their predictions have now unfortunately been proven true in a new study.
The investigation, which was largely conducted on soils in the Southern Hemisphere, proves that large swaths of the world are dying up, and coming under threat from desertification.
Important regions in Australia, Africa and South America are losing their soil moisture, following a natural process called “evapotranspiration.”
The new research was the first ever to examine this phenomenon on a global scale. Its conclusions prove that climate model predicting an increase in evapotranspiration with global warming are true.
By 1998, researchers say that most soils in South America began showing no signs that this process was still operational. Other large areas only lost minimal amount of water to the phenomenon.
This translates into a large-scale pattern of soils drying out, and having no more water to shed into the atmosphere, the research indicates.
Such a large reduction in evapotranspiration also managed to offset some increasing moisture levels at other locations around the world.
Details of the investigation appear in the latest online issue of the top scientific journal Nature.
The team that conducted the work says that it cannot be sure yet whether this trend is a part of natural variability, or if it can be attributed to longer-lasting global change.
This uncertainty stems from the fact that datasets on the phenomenon only span back to 1982. Thirty years is a very short period for researchers to determine the source of an atmospheric phenomenon.
For comparison, the data proving that global warming is happening span more than a century. The earliest organized temperature readings on record were made in 1880.
“This is the first time we've ever been able to compile observations such as this for a global analysis,” explains Oregon State University professor of global change forest science Beverly Law.
“We didn't expect to see this shift in evapotranspiration over such a large area of the Southern Hemisphere” Law goes on to say.
“It is critical to continue such long-term observations, because until we monitor this for a longer period of time, we can't be sure why this is occurring,” he concludes.
Law is a coauthor of the new Nature paper, and also the science director of the AmeriFlux network of 100 research sites.