We often listen that 75% of the planet is covered with water, which gives us the false illusion that there will never be supply problems. But the reality is that less than 1% of accessible water It is suitable for us to drink it. And we are losing it.
In a nutshell, worldwide, fresh water is disappearing, and a new study, published in Science Advances, concludes that much of it is reaching the ocean. The desiccation of the continents It contributes even more to the alarming increase in global sea level than the melting of ice layers.
The authors of the study, led by Hrishikesh Chandanpurkar, conclude that Urgent measures are required to prepare for much drier times that are coming, due to climate change and exhaustion of groundwater by human action.
Using more than two decades of satellite observations of the NASA gravity and weather recovery experiment and its follow -up mission, the Chandanpurkar team created an image of how the storage of land water has changed since 2002 and why.
“We discovered that the continents (the whole land firm, excluding Greenland and Antarctica) have experienced unprecedented desiccation rates And that the continental areas that desiccation experience are increasing approximately twice the size of the California status every year, ”says the study.
If we take into account that California has approximately 424,000 square kilometers and Spain has about 506,000 square kilometers, we are talking about almost double Spain every 365 days. Humanity has seriously modified the water cycle of the Earth by emitting greenhouse gases that alter our atmosphere and divert the river tracks and the rainwater collection basins. While wet areas have become more humid and drier dry areas, these changes are not occurring at the same rate.
“The dry areas are drying at a greater pace than the wet areas -adds the study -. At the same time, the surface that drought has increased, while the surface experienced moisture has decreased. ”
This means that land water, in general, is decreasing, with devastating effects worldwide. This includes superficial fresh water sources, such as lakes and rivers, and also the groundwater stored in aquifers at high depth. The majority of the human population (75 %) lives in the 101 countries where fresh water is being lost at an increasing rate.
The obvious question is where all this water has gone. And the answer is that much closer than we think: mainly to the ocean. This trend towards continental desiccation It is mainly due to the loss of land water in areas such as Canada and Russia (regions that we do not usually consider dry), which the authors suspect that it is due to the melting of ice and permafrost in these regions.
On continents without glaciers, 68 % of the loss of land supply can be attributed to the exhaustion of groundwater for human activity. Recent unprecedented extreme droughts in Central America and Europe have also influenced, and it is expected that events like these will become more frequent and serious with the climatic crisis.
As Our growing fossil fuel emissions alter the rain patterns on which we previously dependedpeople desperately use groundwater, which increases pressure on these water sources, which are not replenished to the rhythm to which they run out.
On many continents, Excessive use of groundwater could be attributed to dry agricultural regions that depend on this water source To water its crops: for example, the Central Valley of California, which produces 70 % of the world’s almonds, and the cotton production near the now dry sea of Aral, in Central Asia. In Spain, meanwhile, almost half of the sub -senarranean aquifers are in poor condition.
“At the moment, Excessive pumping of groundwater is the main cause of the decrease in land water reservesE In the driest regions, which significantly amplifies the impacts of temperature increase, greater aridity and extreme droughts -the study points out -. Protecting the World Water supply is fundamental in a world in warm -up and on continents that, as we know, are drying out. ”
Chandanpurkar team expects efforts, both local and international, to develop sustainable uses of groundwater They contribute to preserve this precious resource for many years.
“While efforts to stop climate change may be stagnant, There is no reason for efforts to curb continental desiccation rates should do the same”, Concludes the study.