According to a new study, groundwater, worsening of droughts and faster evaporation due to higher temperatures caused a drastic drop in the amount of fresh water available.
The “continental drying” has redirected the total water from the planet to the oceans to such a measure that it has now exceeded Melt the glacial caps As a larger contributor to the elevation of the world’s sea level, the research revealed.
Earth’s losses could have deep implications for access to drinking water and the ability to grow food in some of the richest agricultural regions in the world.
“We use a lot of water to cultivate food,” said Jay Famiglietti, professor at the School of Sustainability of Arizona State University and one of the study authors. “If things do not change, we will see impact on our food security and our general availability of water.”
The results “should be essential for the general public, resource managers and decision -makers around the world,” wrote researchers in the studyadding that the trends identified “perhaps send the most recent message on the impact of climate change to date. “
“Continents dry, the availability of fresh water is shrinking and the elevation of sea level is accelerating,” they wrote.
The study, published Friday scientific advances of the journalEvaluated the changes in terrestrial water sources, such as lakes, underground aquifers and humidity in the soil, in the past two decades. Researchers have found that several factors, including climate change, are Disturbing the natural water cycle of the earthDusting how humidity circulates between the soil, the oceans and the atmosphere.
The researchers have used data from a suite of four satellites from NASA to analyze changes in the storage of earthly water in the past 22 years. The satellites were designed to follow the movement of the water from the earth, including modifications of the planet’s glacial caps, glaciers and underground tanks.
Researchers have discovered, for example, that parts of the world already dry have become more dry since 2014. These drought regions have increased by an area twice the size of California each year, said Famiglietti.
In several cases, the hot spots of the drought have developed to create giant and interconnected regions “mega-drying”, according to the study. One of these areas covers parts of Central America, Mexico, California, southwest of the United States, the Lower Colorado River and Southern High Plains basin.
“The key message here is that water is really a key engine of the changes that we see both on land and in the ocean,” said Benjamin Hamlington, researcher in the Earth Sciences section in the NASA jet propulsion laboratory who served in the scientific team for NASA missions which produced the decades of data used in the new study.
The study revealed that each large land mass, with the exception of Greenland and Antarctica, has experienced unprecedented drying since 2002.
Generalized continental drying should have major consequences for people. Three -quarters of the world’s population lives in countries where Freshwater resources are exhaustedAccording to researchers.
Meanwhile, the upward seas are threatening to slip into the coastal regions around the world, which makes them less habitable and adding to increasing pressures caused by extreme storms and floods. In the United States, bad weather has helped trigger an insurance crisis In coastal cities that are subject to extreme weather events.
The link between the elevation of sea level and the loss of water enclosed in the soil is a consequence of the installation of the planet’s water cycle in chaos. Many of these changes, such as groundwater too much of surposing, are considered permanent – or, at the very least, irreversible for thousands or tens of thousands of years, said Alexander Simms, professor in the Department of Earth Sciences at the University of California, Santa Barbara, which was not involved in the study.
“If you remove the water from the continents, the only place where it should go is in the ocean,” he said. “The water goes in the atmosphere, then 88% of this water rains on earth and is found in the ocean.”
Simms said that the study was fascinating in its ability to estimate the global scale of these water losses, but it was skeptical about the assertion that continents’ water loss has now exceeded the ice cap as the greatest contributor to Sea level.
However, Hamlington said The study shows how the movement of water around the planet has enormous training effects. This also suggests that the consequences could intensify in the future, if the groundwater is still exhausted, freshwater resources shrink and that the drought conditions aggravate.
“This type of land water storage is a critical piece of the puzzle,” he said. “If we can follow this water, if we know where it goes, we can improve our understanding of drought, floods and the availability of water resources on earth.”