The losses could be irreversible
Over half of the world’s largest lakes are shrinking.
When lakes shrink, the consequences spread far beyond the shoreline—threatening drinking water, food, livelihoods, wildlife, and even the air we breathe. Lake loss is quietly happening all around the world, at scale. Yet it garners little attention.
60 years ago, the Aral Sea, which spans the Kazakhstan-Uzbekistan border, was the world's fourth largest lake. Today, it’s a shell of its former self; less than 8% remains. What’s left has grown more salty. Rabindranath Tagore, an Indian poet, once quipped that “you can’t cross the sea merely by standing and staring at the water.” He underestimated the destructive power of his fellow man and father time, because today you can literally walk across the Aral seabed.
Source: Google, NASA
Lake Chad, once the world’s 11th largest lake, has lost nearly 95% of its surface area since the 1960s, largely due to reduced rainfall.
The Great Salt Lake, a habitat critical to millions of people and 10 million birds in the United States, has lost roughly half of its surface area relative to its long-term average.
Source: Google, NASA
Lake Prespa, one of the world’s oldest lakes (technically a system of two lakes) that straddles Albania, Greece, and North Macedonia, is disappearing. Great Prespa Lake lost half of its volume between 1984 and 2020. Little Prespa Lake’s surface area has plummeted from 450 hectares in the 1970s to 20 hectares today, with much of it turning into swamps.
Lake Marmara, once a major wildlife and tourist draw in southwestern Türkiye, has lost 98% of its surface area, much of that since 2011. It’s not alone: 186 of Türkiye’s 250 lakes have dried up over the last 50 years, with many shrinking dramatically in the last decade. The UN warns that 88% of the country is at risk of desertification.
Water, water, everywhere
These aren’t isolated instances; this pattern is on repeat globally.
Of the world's 2,000 or so largest lakes, more than half (53%) have shrunk over the past 30 years.
Together, the world’s largest lakes have lost roughly 22 gigatons of surface water per year over that span. That would fill nearly 9 million Olympic-size swimming pools or provide four years of drinking water to the entire global population annually.
Between 2015 and 2023, the world's freshwater lakes, rivers, and aquifers lost an average of 47 litres (12 gallons) of water every day for every person on Earth.
The impacts on communities and ecosystems have been profound
The world has already crossed the planetary boundary for freshwater. That’s the point at which further withdrawal risks destabilising Earth’s systems. Water is under unsustainable pressure, threatening to disrupt the balance that regulates rainfall, runoff, and recharge.
That has implications for anyone who lives by water, relies on water, or drinks water.
The 40,000 person fishing economy that relied on the Aral Sea collapsed as large portions of the lake disappeared and were transformed into toxic salt flats linked to elevated rates of respiratory illness and throat cancer. The Great Salt Lake’s exposed lakebed releases arsenic dust to over 2.5 million people in the US state of Utah. Water loss in Lake Chad has reduced fishing and grazing land, contributing to displacement across a basin that accounts for 8% of the African continent and supports some 30 million people.
One in two people worldwide experiences water-stress at least one month each year.
Without urgent action, the situation will only grow worse.
Humans are at fault
The causes of lake shrinkage vary, but there’s a theme: nearly all are the result of human activity. The most common causes are climate change and diverted water.
Lakes around the world have warmed substantially in recent decades. The Great Salt Lake's surface-water temperature increased by 1.1°C between 2001 and 2021. In Greece, surface temperatures across 18 lakes—including Lake Prespa—increased by an average of 0.43°C per decade between 1981 and 2020, consistent with broader evidence of rapid lake warming globally.
Global lake evaporation increased by roughly 2.1% per decade between 1985 and 2018, largely related to surface warming.
Water diversions for agriculture, industry, and urban use have heavily impacted many large lakes. The Aral Sea, for instance, lost much of its water as a result of Soviet-era cotton irrigation that diverted the Amu Darya and Syr Darya rivers that once fed it. Diversions to the Great Salt Lake cut net inflow by 39%, with 63% of the diverted water going to agriculture.
The importance of early intervention
Stopping or reversing lake water loss requires early intervention. In 2005, Kazakhstan built the Kok-Aral Dam to hold back the last of the Syr Darya river's flow in the North Aral basin. The North Aral stabilised at around 42 metres, while water levels in the South Aral basins continued to decline, dropping to 24 metres and 27 metres.
Unfortunately, early intervention seldom happens. The history of the Great Salt Lake is illustrative. For much of the last two centuries, most lake-related decisions were extractive: water rights granted, tributaries dammed, causeways built. In 2017, a group of water scientists published a study warning of the looming collapse of the Great Salt Lake and other saline lakes. Little changed. In 2022, the lake reached its lowest recorded level in 175 years, garnering national attention. That triggered a flurry of government action, but the fate of the lake remains far from certain.
Institutional cooperation alone isn't sufficient. Lake Prespa has been governed under a joint preservation agreement between Albania, Greece, and North Macedonia since 2000. Yet the lake is still in decline, with surface levels dropping three metres over the last decade. Long-term solutions will require tackling the root causes of lake decline, most notably climate change and excess water use.