Terrestrial Water Is Changing Worldwide And Climate Change Is Responsible

Observations show that the available volume of water has been falling in some regions of the world for a few decades. One example is southern Europe, where aridity is increasing. But in other areas water supplies are trending upwards.

The causes of this change in water availability pose an urgent question – and not only for those countries suffering from acute water shortages.

Is anthropogenic climate change to blame, or is it simply random fluctuations in the climate system?

To date, there has been no definitive answer at a global level.

It is scientifically indisputable that increased atmospheric concentrations of CO₂ influence the complex global water cycle in various ways. But until now it has been impossible to prove a direct effect of global warming on available terrestrial water resources over recent decades. The historical observation series, sometimes too brief and qualitatively inadequate, did not enable exclusion of natural climate variability as the cause of the changes observed.

To determine how water availability changed over time, the researchers compared data between 1985 to 2014 with those of the first half of the 20th century. They mapped out a global pattern of changes in available water over the past three decades and found the fingerprint of climate change.

“We were able to show that this global pattern of observed changes is consistent with the effects of human-induced climate change and highly unlikely to be the product of natural fluctuations,” Ryan Padrón, a postdoc in Seneviratne’s group and lead author of the study, said in a press release.

According to researchers, the study shows a tendency towards greater aridity in the northern mid-latitudes – which include, for example, Switzerland – where conditions have become drier in summer months.”

In general, the reconstructed water availability data point to more intense dry seasons in extratropical latitudes. Affected regions include Europe, western North America, northern Asia, southern South America, Australia, and East Africa. The researchers note that the increased intensity of dry seasons is generally caused by greater evaporation (due to higher temperatures and radiation) rather than reduced precipitation.

But there are also regions in which the volume of available water has increased in dry seasons, including the interior of China, Southeast Asia, and the Sahel region.

Research

Written by Eddie Gonzales Jr. – MessageToEagle.com Staff