We only have so much water on Earth. Water is not created or destroyed but instead cycled through a finite system.
Although the amount of water is fixed, its distribution throughout the system is always changing, which makes it very hard to know if usage in any one area is sustainable. Climate change only aggravates this problem.
As a result, scientists cannot define a water budget with confidence. This issue is addressed in a recent study led by the ESA Climate Change Initiative. The paper highlights new attempts by science to closely observe Earth’s water cycle to account for the planet’s entire supply of water and ice.
“We’ve made a lot of advances, especially in space-based observations of the water cycle. The Copernicus programme is proving vital for long-term, consistent satellite observations,” said study lead author Wouter Dorigo of Vienna University of Technology.
The new observations take advantage of satellites to observe much of Earth’s water cycle. However, as Dorigo explains, there are still serious blind spots.
“In particular, we don’t have accurate knowledge of the fluxes for groundwater use, recharge and natural discharge, which makes it difficult to project future sustainable use.”
“Currently, satellites alone cannot resolve the entire water budget balance. Coordinated measurements of groundwater from sensors in the ground is what we need most urgently, as well as more data on water used by us humans as well as data on river discharge.”
The largest source of freshwater on Earth is groundwater, something that is still hard for scientists to monitor with certainty.
The researchers call for the development of better technology and techniques to monitor the Earth’s water and usage with more accuracy. A new effort aims at “weighing” all the water on the earth, including groundwater as a way forward.
The study is published in the Bulletin of the American Meteorological Society.