The global water cycle is out of balance for the first time

For the first time in history, humans are disrupting the balance of the global water cycle, causing increasingly serious water disasters, with expected negative impacts on life, the economy and the food production sector, according to Report released on October 16 by the Global Water Economy Commission – an organization of international experts and leaders. Decades of destructive land use and poor water management combined with the man-made climate crisis have put “unprecedented pressure” on the global water cycle, the report said. .

The water cycle is the complex cycle by which water moves around the Earth. Water evaporates from the ground – for example from lakes, rivers, plants – and rises into the atmosphere, forming large streams of water vapor that can travel long distances, then cool, condense, and finally fall back to the surface land in the form of rain or snow.

Disrupted water cycles have many consequences. Nearly 3 billion people face water scarcity. Crops are withering and cities are sinking as the groundwater below dries up. The consequences will be even more dire if the world does not act urgently. The water crisis threatens more than 50% of global food production and threatens to reduce countries’ GDP by an average of 8% by 2050. In low-income countries, the expected losses are much higher, reaching up to 15%, according to a report on October 16.

“For the first time in human history, we are pushing the global water cycle out of balance. We can no longer rely on rain, the source of all fresh water,” said Johan Rockstrom, fellow said the chair of the Global Water Economy Commission, one of the authors of the new report.

The report distinguishes between “blue water”, liquid water in rivers, lakes and aquifers, and “green water”, moisture stored in soil and plants. Although often overlooked, green water supplies are also important to the water cycle because water returns to the atmosphere when plants release water vapor, creating about half of all precipitation on land.

Disruptions in the water cycle are deeply linked to climate change, the report says. A steady supply of green water is key to helping plants capture carbon – the element that heats the planet. But human damage, including the destruction of wetlands and deforestation, is weakening these “carbon sinks” and accelerating global warming. On the other hand, warming also causes landscapes to dry out, reduce humidity and increase the risk of wildfires.

The report calls for “fundamental changes to water’s place in the economy,” including better pricing to avoid waste and growing crops or building water-intensive facilities, such as data centers. materials, in areas lacking water.

“The global water crisis is a tragedy but also an opportunity to transform the water economy,” said Ngozi Okonjo-Iweala, director general of the World Trade Organization and co-chair of the Commission on the Global Water Economy. request, tell. She added that appreciating the value of water is extremely necessary to realize that water is scarce and brings many benefits.