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lite.cnn.com - on gopher - inofficial
ARTICLE VIEW:
Global water cycle off balance for ‘first time in human history,’
threatening half the planet’s food production
By Laura Paddison, CNN
Updated:
6:00 PM EDT, Wed October 16, 2024
Source: CNN
Humanity has thrown the global water cycle off balance “for the first
time in human history,” fueling a 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 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 . and 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.”
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.
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.
The report calls for a “fundamental regearing of where water sits in
economies,” including better pricing to discourage wastefulness and
the tendency to plant and facilities, such as , 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.”
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