- Madrid's Carvajal to miss several months after serious knee injury
- Two elephants die in flash flooding in northern Thailand
- Sabalenka targets world number one and Wuhan hat-trick
- Tunisia votes with Saied set for re-election
- Bagnaia sets 'example' with Japan MotoGP win to cut gap on Martin
- Intense Israeli bombing rocks Beirut ahead of war anniversary
- Mozambique vote: no suspense but some disillusion
- Austrian rapper channels anti-racist rage in Romani hip-hop songs
- Ohtani magic powers Dodgers over Padres in MLB playoff thriller
- Five of the best: Pakistan-England Test thrillers
- Man sets arm on fire as marches across US mark Gaza war anniversary
- Vietnam's young coffee entrepreneurs brew up a revolution
- Trump rallies at site of failed assassination: 'Never quit'
- Too hot by day, Dubai's floodlit beaches are packed at night
- Is music finally reckoning with #MeToo?
- Fans hail Trump's 'guts' as he returns to site of rally shooting
- Lebanon state media says Israeli strikes hit south Beirut
- Miami on track for MLS record points after win in Toronto
- Monaco take top spot in Ligue 1 with win at Rennes
- Madrid beat Villarreal to level Liga leaders Barca
- Thuram treble fires Inter past Torino and up to second
- 'Fight': defiant Trump jets in to site of rally shooting
- Mexico City's new mayor sworn in with pledges on water, housing
- Israel on alert ahead of Hamas attack anniversary
- Guardians maul Tigers in MLB playoff series opener
- Macron criticises Israel on Gaza, Lebanon operations
- French rugby player whistled but 'serene' on return amid ongoing rape case
- Retegui hat-trick fires five-star Atalanta to hammering of Genoa
- Heavyweights Australia, England off to World Cup winning starts
- Visiting UN refugee agency chief decries 'terrible crisis' in Lebanon
- Spinners come to party as England defeat Bangladesh at T20 World Cup
- Search continues for missing in deadly Bosnia floods
- Man City sink Fulham to get title bid back on track
- France's Auradou whistled on Pau return in Perpignan loss amid ongoing rape case
- A 'forgotten' valley in storm-hit North Carolina, desperate for help
- Arsenal hit back in style after Southampton scare
- Hezbollah heir apparent Safieddine out of contact after strikes
- Liverpool stay top of Premier League as Arsenal, Man City win
- In dank Tour of Emilia, Pogacar shines in rainbow jersey
- DR Congo launches mpox vaccination drive, hoping to curb outbreak
- Trump returns to site of failed assassination
- Careless Leverkusen held to Bundesliga draw
- O'Brien's 'superstar' Kyprios posts landmark win on Arc weekend
- Liverpool suffer Alisson injury blow
- Habosi helps Racing beat Vannes before Auradou's playing return
- Thousands march in London in support of Palestinians, 1 year after Oct 7
- Israel readying response to Iran missile attack
- Schutt, Mooney help Australia beat Sri Lanka in Women's T20 World Cup
- Liverpool extend Premier League lead with win at Palace
- Djokovic 'shakes rust off' to make third round of Shanghai Masters
Half world's largest lakes and reservoirs drying up: study
More than half of the world's largest lakes and reservoirs are dwindling and placing humanity's future water security at risk, with climate change and unsustainable consumption the main culprits, a study said Thursday.
"Lakes are in trouble globally, and it has implications far and wide," Balaji Rajagopalan, a professor at the University of Colorado Boulder and co-author of the paper, which appeared in Science, told AFP.
"It really caught our attention that 25 percent of the world's population is living in a lake basin that is on a declining trend," he continued, meaning some two billion people are impacted by the findings.
Unlike rivers, which have tended to hog scientific attention, lakes aren't well monitored, despite their critical importance for water security, said Rajagopalan.
But high profile environmental disasters in large water bodies like the Caspian Sea and the Aral Sea, signaled to researchers a wider crisis.
To study the question systematically, the team, which included scientists from the United States, France, and Saudi Arabia, looked at Earth's biggest 1,972 lakes and reservoirs, using observations from satellites from 1992-2020.
They focused on larger freshwater bodies because of the better accuracy of satellites at a larger scale, as well as their importance for humans and wildlife.
- 17 Lake Meads lost -
Their dataset merged images from Landsat, the longest-running Earth observation program, with water surface height acquired by satellite altimeters, to determine how lake volume varied over nearly 30 years.
The results: 53 percent of lakes and reservoirs saw a decline in water storage, at a rate of approximately 22 gigatonnes a year.
Over the whole period studied, 603 cubic kilometers of water (145 cubic miles) was lost, 17 times the water in Lake Mead, the United States' largest reservoir.
To find out what drove the trends, the team used statistical models incorporating climate and hydrologic trends to tease out natural and human-driven factors.
For natural lakes, much of the net loss was attributed to climate warming as well as human water consumption.
Increased temperatures from climate change drive evaporation, but can also decrease precipitation in some places.
"The climate signal pervades all factors," said Rajagopalan.
Lead author Fangfang Yao, a visiting fellow at CU Boulder, added in a statement: "Many of the human and climate change footprints on lake water losses were previously unknown, such as the desiccations of Lake Good-e-Zareh in Afghanistan and Lake Mar Chiquita in Argentina."
- Losses in humid regions, too -
One surprising aspect was that lakes in both wet and dry regions of the world are losing volume, suggesting the "dry gets drier, wet gets wetter" paradigm that is frequently used to summarize how climate change affects regions, doesn't always hold.
Losses were found in humid tropical lakes in the Amazon as well as Arctic lakes, demonstrating a trend more widely spread than predicted.
Accumulating sedimentation was blamed for storage loss in drying reservoirs.
But although most global lakes were dwindling, nearly a quarter saw significant increases in their water storage.
These included in the Tibetan Plateau, "where glacier retreat and permafrost thawing partially drove alpine lake expansion," the paper said.
Hilary Dugan, a scientist who studies freshwater systems at the University of Wisconsin-Madison and who wasn't involved in the study, told AFP the research advanced scientific understanding of lake volume variability, which is of "huge importance."
It is "unique in that it focuses on specific lakes, and reports the amount of water as a volume," she said.
But she added: "It's important to keep in mind that many water supplies are from small lakes and reservoirs," and future research should consider these too.
Globally, freshwater lakes and reservoirs store 87 percent of the planet's liquid freshwater, underscoring the urgency of new strategies for sustainable consumption and climate mitigation.
"If a good chunk of freshwater lakes are drying, then you're going to see the impact come to you one way or the other, if not now in the not too distant future," said Rajagopalan.
"So it behooves all of us to be good stewards."
H.Silva--PC