Thursday, October 17, 2024

The system that moves water around the Earth is off balance for the first time in human history

Laura Paddison
CNN
Wed, October 16, 2024 


Humanity has thrown the global water cycle off balance “for the first time in human history,” fueling a growing water disaster that will wreak havoc on economies, food production and lives, according to a landmark new report.

Decades of destructive land use and water mismanagement have collided with the human-caused climate crisis to put “unprecedented stress” on the global water cycle, said the report published Wednesday by the Global Commission on the Economics of Water, a group of international leaders and experts.

The water cycle refers to the complex system by which water moves around the Earth. Water evaporates from the ground — including from lakes, rivers and plants — and rises into the atmosphere, forming large rivers of water vapor able to travel long distances, before cooling, condensing and eventually falling back to the ground as rain or snow.

Disruptions to the water cycle are already causing suffering. Nearly 3 billion people face water scarcity. Crops are shriveling and cities are sinking as the groundwater beneath them dries out.

The consequences will be even more catastrophic without urgent action. The water crisis threatens more than 50% of global food production and risks shaving an average of 8% off countries’ GDPs by 2050, with much higher losses of up to 15% projected in low-income countries, the report found.

“For the first time in human history, we are pushing the global water cycle out of balance,” said Johan Rockström, co-chair of the Global Commission on the Economics of Water and a report author. “Precipitation, the source of all freshwater, can no longer be relied upon.”


Graphic showing the movement of "green water" and "blue water" in the global water cycle. - Global Commission on the Economics of Water

The report differentiates between “blue water,” the liquid water in lakes, rivers and aquifers, and “green water,” the moisture stored in soils and plants.

While the supply of green water has long been overlooked, it is just as important to the water cycle, the report says, as it returns to the atmosphere when plants release water vapor, generating about half of all rainfall over land.

Disruptions to the water cycle are “deeply intertwined” with climate change, the report found.

A stable supply of green water is vital for supporting vegetation that can store planet-heating carbon. But the damage humans inflict, including destroying wetlands and tearing down forests, is depleting these carbon sinks and accelerating global warming. In turn, climate change-fueled heat is drying out landscapes, reducing moisture and increasing fire risk.

The crisis is made more urgent by the huge need for water. The report calculates that, on average, people need a minimum of about 4,000 liters (just over 1,000 gallons) a day to lead a “dignified life,” far above the 50 to 100 liters the United Nations says is needed for basic needs, and more than most regions will be able to provide from local sources.

A boat on the Rio Negro in Manaus, Brazil, on October 9, 2024, as the river reached its lowest level on record during the most intense and widespread drought the country has experienced since 1950. - Bruno Kelly/Reuters

Richard Allan, a climate science professor at Reading University, England, said the report “paints a grim picture of human-caused disruption to the global water cycle, the most precious natural resource that ultimately sustains our livelihoods.”

Human activities “are altering the fabric of our land and the air above which is warming the climate, intensifying both wet and dry extremes, and sending wind and rainfall patterns out of kilter,” added Allan, who was not involved in the report.

The crisis can only be addressed through better management of natural resources and massive cuts in planet-heating pollution, he told CNN.

The report’s authors say world governments must recognize the water cycle as a “common good” and address it collectively. Countries are dependent on each other, not only through lakes and rivers that span borders, but also because of water in the atmosphere, which can travel huge distances — meaning decisions made in one country can disrupt rainfall in another.


Dead almond trees removed by a farmer because of a lack of water to irrigate them, in drought-stricken Huron, California, on July 23, 2021. - Robyn Beck/AFP/Getty Images

The report calls for a “fundamental regearing of where water sits in economies,” including better pricing to discourage wastefulness and the tendency to plant water-thirsty crops and facilities, such as data centers, in water-stressed regions.

“The global water crisis is a tragedy but is also an opportunity to transform the economics of water,” said Ngozi Okonjo-Iweala, director general of the World Trade Organization and a co-chair of the commission that published the report. Valuing water properly is essential, she added, “so as to recognize its scarcity and the many benefits it delivers.”



Water crisis driven by climate change threatens global food production

RFI
Thu, October 17, 2024 


The exposed sandbanks of the Paraguay River, near Villeta, Paraguay, 12 October 2024. The river's water levels have dropped dramatically due to a drought in Brazil, upstream, which has fuelled a conflict between fishermen and rice farmers over water use.


The world’s supplies of fresh water can no longer be counted on due to a shift in rainfall patterns caused by climate change, a major report has warned. It's calling for global cooperation to address a problem that could put more than half of the world’s food production at risk by 2050.

Climate change, destructive land use and mismanagement of supplies has put the global water cycle under "unprecedented stress", the Global Commission on the Economics of Water (GCEW) warned in a report published Thursday.

"Nearly three billion people and more than half of the world's food production are now in areas where total water storage is projected to decline," said the GCEW, a two-year research initiative set up by the Netherlands in 2022.

Densely populated regions are especially vulnerable to freshwater shortages, it said, including northwestern India, northeastern China and southern and eastern Europe.

Agriculture is impacted, with global cereal production falling by as much 23 percent if current trends continue.

Vicious cycle

Disruptions of the water cycle "have major global economic impacts," said the report.


OECD-backed group calls for global pact to solve water crisis

David Stanway
Wed, October 16, 2024 

Drought on the Italian Island of Sicily


By David Stanway

SINGAPORE (Reuters) - Countries need a new international pact to fix a mounting water crisis that could cut economic growth by at least 8% and put half the world's food supplies at risk by 2050, an OECD-backed commission said on Thursday.

Climate change, destructive land use and chronic mismanagement has put the global water cycle under "unprecedented stress", said the Global Commission on the Economics of Water (GCEW), a two-year research initiative set up by the Netherlands in 2022.

Densely populated regions like northwestern India, northeastern China and southern and eastern Europe are especially vulnerable to water shortages, it said.

Governments must work together to create incentives to transform how water is consumed and ensure that investment in vital infrastructure reaches the right places, GCEW said in its final report.

"We are going to have to set common goals for water sustainability," said Singapore President Tharman Shanmugaratnam, GCEW co-chair.

"Ultimately, it will require a global water pact. It is going to take several years to get there, but we are going to start that process," he said at a briefing ahead of the report's launch.

The report said global water supplies can no longer be counted on, partly as a result of shifting rainfall patterns, with each 1 degree Celsius of warming estimated to increase atmospheric moisture retention by 7%.

"For the first time, we are actually changing the very source of all freshwater - namely precipitation," said Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research and another commission co-chair.

As well as "blue water" in rivers and lakes, the commission looked at "green water" contained in soils and plant life. After evaporating, green water provides around half of global rainfall in a process known as "atmospheric rivers".

Rising temperatures have created a vicious cycle, with lower soil moisture worsening droughts and wildfires and causing more degradation and biodiversity loss, further disrupting those atmospheric river flows, the commission said.

Regions relying on high levels of irrigation could suffer from water storage capacity declines. On current trends, global cereal production could fall by as much 23%.

Financing mechanisms are required to encourage investment in water infrastructure, especially in more vulnerable countries, and banks should also make lending conditional on protecting water supplies, the report said.

Global efforts are also needed to price water correctly and "redeploy" an estimated $600 billion in annual agriculture subsidies that encourage overconsumption and the planting of water-intensive crops in unsuitable regions, said Ngozi Okonjo-Iweala, Director General of the World Trade Organization and another GCEW co-chair.

While multilateral cooperation is needed to address threats to global water supplies, growing shortages could aggravate geopolitical tensions, said Genevieve Donnellon-May, a researcher at the Oxford Global Society think tank, who studies water politics.

"One worry is that growing water scarcity could lead to less transboundary cooperation, both at a subnational level… and also between nations," she said.

(Reporting by David Stanway; Editing by Devika Syamnath)

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