Overpumping groundwater, worsening droughts and more rapid evaporation due to higher temperatures have caused a drastic decline in the amount of available freshwater, according to a new study.<\/p>\n
\u201cContinental drying\u201d has redirected the planet\u2019s total water to the oceans to such degree that it has now surpassed melting ice sheets<\/a> as the biggest contributor to global sea level rise, the research found. <\/p>\n Losses of land-based water could have profound implications for access to safe drinking water and the ability to grow food in some of the world\u2019s richest agricultural regions.<\/p>\n \u201cWe use a lot of water to grow food,\u201d said Jay Famiglietti, a professor at Arizona State University\u2019s School of Sustainability and one of the authors of the study. \u201cIf things don\u2019t change, we\u2019ll see impacts on our food security and just our general water availability.\u201d<\/p>\n The findings \u201cshould be of paramount concern to the general public, to resource managers, and to decision-makers around the world,\u201d the researchers wrote in the study<\/a>, adding that the identified trends \u201csend perhaps the direst message on the impact of climate change<\/a> to date.\u201d<\/p>\n \u201cThe continents are drying, freshwater availability is shrinking, and sea level rise is accelerating,\u201d they wrote.<\/p>\n The study, published Friday in the journal Science Advances<\/a>, assessed changes in terrestrial water sources, such as lakes, underground aquifers and moisture in soil, over the past two decades. The researchers found that several factors, including climate change, are disrupting Earth\u2019s natural water cycle<\/a>, upsetting how moisture circulates between the ground, oceans and atmosphere. <\/p>\n The researchers used data from a suite of four NASA satellites to analyze changes in terrestrial water storage over the past 22 years. The satellites were designed to track the movement of Earth\u2019s water, including changes to the planet\u2019s ice sheets, glaciers and underground reservoirs.<\/p>\n The researchers found, for instance, that parts of the world that are already dry have been rapidly getting drier since 2014. These drought-ridden regions increased by an area twice the size of California each year, Famiglietti said. <\/p>\n In several cases, drought-ridden hotspots expanded to create giant, interconnected \u201cmega-drying\u201d regions, according to the study. One such area covers parts of Central America, Mexico, California, the southwestern United States, the lower Colorado River basin and the southern High Plains.<\/p>\n \u201cThe key message here is that water is really a key driver of the changes we see both on land and in the ocean,\u201d said Benjamin Hamlington, a research scientist in the Earth Sciences Section at NASA\u2019s Jet Propulsion Laboratory who served on the science team for the NASA missions that produced the decades of data used in the new study. <\/p>\n The study found that every large land mass, except for Greenland and Antarctica, has experienced unprecedented drying since 2002. <\/p>\n Widespread continental drying is expected to have major consequences for people. Three quarters of the world\u2019s population lives in countries where freshwater resources are being depleted<\/a>, according to the researchers.<\/p>\n Meanwhile, rising seas threaten to creep up on coastal regions around the globe, making them less habitable and adding to the mounting pressures caused by extreme storms and floods. In the U.S., severe weather has helped trigger an insurance crisis<\/a> in coastal cities that are prone to extreme weather events.<\/p>\n The link between sea-level rise and the loss of water locked up in the ground is a consequence of throwing the planet\u2019s water cycle into chaos. Many of these changes, such as overpumping groundwater, are thought to be permanent \u2014 or, at the very least, irreversible for thousands or tens of thousands of years, said Alexander Simms, a professor in the Department of Earth Science at the University of California, Santa Barbara, who was not involved with the study.<\/p>\n \u201cIf you pull water off the continents, the only place it has to go is in the ocean,\u201d he said. \u201cWater goes in the atmosphere, then 88% of that water rains down on Earth and ends up in the ocean.\u201d<\/p>\n