New global study shows freshwater is disappearing at alarming rates

New results in the study of more than two decades of satellite observations reveal that the continents of the earth have undergone unprecedented freshwater loss since 2002, driven by climate change, unsustainable use of groundwater and extreme droughts. The study, led by the Arizona State University and published today Scientific advances, Underlines the emergence of four regions of “mega-drying” on a continental scale, all located in the northern hemisphere, and warns against the serious consequences for water safety, agriculture, elevation of sea level and global stability.

The research team reports that drying areas on earth are developing at a rate of California about twice every year. And, the speed at which dry areas become drier now exceed the speed at which wetlands become humid, reversing longtime hydrological patterns.

The negative implications of this for available fresh water are astounding. 75% of the world’s population has lived in 101 countries that have lost fresh water for 22 years. According to the United Nations, the world’s population should continue to grow over the next 50 to 60 years – at the same time, the availability of fresh water is narrowed considerably.

The researchers identified the type of water loss on earth and, for the first time, found that 68% came from groundwater alone – contributing more to the elevation of the sea level than the glacial caps of Greenland and the combined Antarctic.

“These results perhaps send the most alarming message to date on the impact of climate change on our water resources,” said Jay Famiglietti, principal of the study and a global term teacher at the ASU sustainability school. “The continents dry, the availability of fresh water is shrinking and the elevation of sea level is accelerating. The consequences of continuous overuse of groundwater could undermine the safety of food and water for billions of people in the world.

Researchers have evaluated more than two decades of data from the recovery of American and climatic severity (thanks) and grace on (Grace-Fo), looking at how and why the storage of earthly water has changed since 2002. The storage of earthly water includes the entire surface and vegetation of the earth, soil humidity, ice, snow and groundwater stored on earth vegetation.

“It is striking of the amount of non -renewable water that we lose,” said Hrishikesh A. Chandanpurkar, principal of the study and researcher for the ASU. “Glaciers and deep groundwater are a kind of old fiduciary funds. Instead of using them only if necessary, such as prolonged drought, we take them for acquired. In addition, we do not try to reconstruct the groundwater systems during humid years and thus towards an imminent expansion of enlargement.”

Tilting point and aggravating continental drying

The study identified what seems to be a tilting point around 2014-2015 for a period considered as “Mega el-Niño”. The climatic extremes began to accelerate and, in response, the use of groundwater has increased and continental drying has exceeded glacier levels and the fusion of the ice cap.

In addition, the study revealed an oscillation previously not declared where after 2014, the drying regions took place mainly in the southern hemisphere to most north, and vice versa for wet regions.

One of the main engines contributing to continental drying is the growing extremes of drought in the average latitudes of the northern hemisphere, for example in Europe. In addition, in Canada and in Russia, snow, ice and permafrost, fusion has increased in the last decade, and continuous deletion of groundwater in the world is a major factor.

In a previous study, the team members studied the storage of terrestrial water from satellite data covering 2002-2016. In the new study, the team examined more than 20 years of data and discovered a critical and major development of continental drying. Several regional drying models and “hot spots” previously located for the loss of terrestrial water storage are now interconnected – forming the four mega drying regions on a continental scale.

These include:

• North Southwest and Central America: this region includes regions producing food products in the American southwest, as well as large desert cities such as Phoenix, Tucson, Las Vegas and large metropolitan areas such as Los Angeles and Mexico.
• Alaska and northern Canada: This region includes the melting of alpine glaciers in Alaska and British Columbia, snow and permafrost found through large Canadian latitudes and drying in large agricultural regions such as British Columbia and Saskatchewan.
• North of Russia: this region knows the major snow and the melting of permafrost through high latitudes
• Pan-Eurasia of the Middle East-Nord (MENA): this region includes major desert cities, notably Dubai, Casablanca, Cairo, Baghdad and Tehran; The main food production regions such as Ukraine, northwest India and the Chinese region of the Plaine de North China; The Caspian and Aral narrowed; And big cities like Barcelona, Paris, Berlin, Dhaka and Beijing.

In fact, the study has shown that since 2002, only the tropics have continued to become wet on average by latitude, which is not predicted by the climate models of IPCC (intergovernmental panel on climate change) – sophisticated computer programs used to project future climatic scenarios. Continuous records are essential to understand the long -term changes in the water cycle.

“This study really shows how important it is to have continuous observations of a variable such as the storage of earthly water,” said Chandanpurkar. “Grace’s recordings really reach the length where we are able to see the long -term trends in climate variability.

A planetary alarm clock

The unprecedented scale of continental drying threatens agriculture and food security, biodiversity, fresh water supplies and global stability. This study highlights the need for large -scale research to inform decision -makers and communities of worsening challenges and water opportunities to create a significant change.

“This research is important. It clearly shows that we need new groundwater management policies and strategies worldwide,” Famiglietti told Julie Ann Wrigley Global Futures Laboratory and former aquatic scientist at the NASA jet propulsion laboratory. “Although efforts to mitigate climate change is confronted with challenges, we can approach continental drying by implementing new policies concerning regional and international sustainable sustainability.

The study calls for immediate action to slow down and reverse the exhaustion of groundwater, protect remaining fresh water resources and adapt to the growing risk of water rarity and coastal flood. The research team continues by saying that strategic water management, international cooperation and sustainable policies are essential to preserve water for future generations and to mitigate the damage caused by planetary systems.

Research will also support a next flagship report from the World Bank group which will deepen these results, including the human and economic implications of continental drying, and current solutions for countries to meet the growing freshwater crisis.

The results are based on more than 22 years of terrestrial water storage data for American satellite missions German Grace and Grace-Fo. The complete report details scientific analyzes and regional failures of drying trends, which have proven robust and persistent despite climate variability.

The research team includes scientists from Arizona State University; Hrishikesh A. Chandanpurkar, Flame University; John T. REAGER and David N. Wiese, JPL; Kaushik Gopalan and Yoshihide Wada, King Abdullah University of Sciences and Technologies; Kauru Kakinuma, Korea Advanced Institute of Science and Technology; And Fan Zhang, the World Bank.