The results of a 14-year long mission, GRACE show strange shift in fresh water over the world. As per the data collected from the mission which covered years from 2002 to 2016, the poles are losing their ice sheets, the middle latitudes are getting drier and the higher latitudes are reporting an increase in the amount of water.
As much as this pattern of the climate change model is normal (and was predicted), the rate with which changes are happening isn’t. The blame, therefore, falls upon the ones using the most essential resource on earth carelessly.
The team that was led by Matt Rodell has marked 34 hotspots where the change took place abruptly. The countries that lie in the middle latitudes are the most populous ones which include India, China, and Australia. Hence, the lack of fresh water in these areas could really be a big challenge for the whole world. The extraction of groundwater for the purpose of irrigation of wheat and rice is the main cause of the dryness in North-India. It has been noted that the Earth’s growing temperature has little to do with the aridness as it rained normally throughout the years. The dams built in Iraq, Syria, and China over the past few years have contributed in over-reliance of underground water in the respective countries.NASA, after Rodell et al., 2018.
California lost 4 gigatonnes of fresh water per year, Xinjiang’s province 5.5 gigatonnes, Saudi Arabia 6.1 gigatonnes and an Africa’s country lost 29 gigatonnes from 2002 to 2016, due to heavy reliance on groundwater.
James Famiglietti, of the Nasa Jet Propulsion Laboratory in California, and co-author of the paper that published in ‘Nature’ said “What we are witnessing is major hydrologic change. We see for the first time a very distinctive pattern of the wetland areas of the world getting wetter, in the high latitudes and the tropics, and the dry areas in between getting drier. Within the dry areas, we see multiple hotspots resulting from groundwater depletion. The pattern of wet-getting-wetter, dry-getting-drier during the rest of the 21st century is predicted by the Intergovernmental Panel on Climate Change models, but we’ll need a much longer dataset to be able to definitively say whether climate change is responsible for the emergence of any similar pattern in the GRACE data.”
GRACE, Gravity Recovery, and Climate Experiment was a NASA and German Aerospace Centre spacecraft mission which consisted of twin satellites measuring the mass around the Earth. Though the experiment came to an end. It’s follow up, NASA’s Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) is expected to launch this very month which will further make the cause of the depletion of freshwater clear.
Not to forget, the amount of water it is required to produce food, we should not take its availability as granted, Famiglietti expressed his views to the press. He continued that the humanity is at that point in time that these aquifers show a fatal decline and we can’t take it for granted anymore, in his words, “Population is too great, groundwater levels are too low. … we’re at tipping points.”