Blue No More Part 3: No More Lakes

Part 1, Part 2

In the last two parts of this series, I've talked about two of the more significant lakes that are currently drying up, but they're by no means isolated. Lakes around the world are drying up, leaving horrifying environmental crises in their wakes. This is an ongoing, high-threat environmental issue that endangers millions of people around the world.

The drying up of Lake Chad. [Image source]

Of the lakes dying out currently, one of the most critical is Lake Chad. Lake Chad provides water to more than 30 million residents of the four African nations bordering it. Once one of the largest lakes in Africa, it declined more than 95% in size over the latter half of the 20th century, though it has recovered a bit in size during the 21st century. Unlike the other two lakes we've discussed so far, the forces fighting over the fate of the lake have much more of a power balance. The fishermen on Lake Chad are actually able to politically stand up to the farmers and industry draining the lake, and the surrounding nations (Nigeria, Chad, Cameroon, and Niger) have actually committed resources towards fighting the lake's decline. While in many respects Lake Chad is very different than the Salton or Aral seas, it has one major thing in common with a great number of the other lakes drying up most swiftly- they're endorheic lakes.

Endorheic lakes are lakes that do not drain into the sea. Somewhat counter-intuitively, they're much more vulnerable to drying up than lakes that do drain out into the sea. Endorheic lakes are so much more vulnerable for a few reasons. First of all, they're usually located in desert regions far inland. These things are closely related. Most (though by no means all) of the world's great deserts are inland- coastal regions just tend to be wetter. When farther inland, there are also more likely to be topographic barriers preventing the water from draining out into the sea. This is compounded by the fact that in high rainfall regions, water is more able to cut through topographic barriers to reach the sea. Since endorheic lakes are usually in arid regions, they're simply much less robust than lakes with outlets, since they're simply getting less water into them.

Satellite views of the Dead Sea, bordered by Israel and Jordan. The ultrasaline Dead Sea is another endorheic lake that faces potential extinction thanks to the diversion of 90% of the water of the Jordan River from the Sea of Galilee to the Dead Sea. Due to its strong economic importance, however, Jordan is carrying out a project known as the Red Sea-Dead Sea Conveyance. This (preferably underground) canal will bring water from the Red Sea all the Way to the Dead Sea. Along the way, fresh water will be extracted from it to provide potable water to Jordan, Israel, and Palestine, leaving the briny remainder to restore the Dead Sea. [Image source]

Next, there's the fact that many endorheic lakes tend to be extremely shallow compared to other lakes. Or, rather, they tend to have larger surface to depth ratios than other lakes. This isn't always true- some, like the Dead Sea, are quite deep. Others, however, like Lake Poopó of Bolivia, covered over 1,000 square kilometers (390 square miles), and yet averaged only 3 meters (10 feet) deep. This high surface to volume ratio allows much faster evaporation than deeper lakes, leading to a highly variable size depending on seasonal rainfall and input. When human projects divert rivers entering endorheic lakes, they rapidly evaporate.

Other endorheic lakes face a similar water loss problem not from evaporation, but from penetrating underground. Water from any lake will slowly penetrate the ground to enter the groundwater supply, but lakes in karst (limestone dominated) terrain drain due to penetration much, much more swiftly than other lakes. (Though not necessarily faster than drainage by evaporation.) This is due to the unusual properties of limestone compared to other stone. Limestone, a calcium carbonate rock, is actually water soluble over geological time, causing water to drain into it rapidly. This is also the same reason the overwhelming majority of the world's caves form in karst terrain.

Lake Poopó in 2006. The lake was once the size of Rhode Island, but by 2015, the lake had vanished entirely, and is not expected to return. This has crippled local fishing communities, ending a way of life for the native Uru people that has lasted millenia. The loss of Lake Poopó is due to lower water levels in Lake Titicaca, whose main outlet, the Desaguadero River, leads straight into Poopó. When the water level drops below a certain depth in Lake Titicaca (which it has, for a variety of reasons, including the loss of most of the glaciers that once fed it), the Desaguadero River stops carrying enough water to counterbalance the huge amounts of evaporation Lake Poopó undergoes due to its shallow depth and large surface area.[Image source]

A good way to sum up the reason why endorheic lakes are more vulnerable is that conventional lakes with drainage face considerable topographic pressure to drain them, so if they do exist, they already have to be fairly hydrologically robust. Endorheic lakes, on the other hand, can easily form in extremely marginal conditions. Indeed, geologists have shown that a great number of endorheic lakes either get large enough to break through to the ocean (like the Black Sea did), undergo periodic cycles of growth and shrinkage, or are simply extremely short lived. Human action is simply overburdening these delicate lake systems, vastly accelerating drainage processes.

While most of the impacted lakes we've discussed so far have been primarily affected by human drainage of either intake rivers or the lake itself, climate change presents a serious threat to these lakes as well. Increased summer temperatures worldwide, more frequent and deeper droughts, and changed wind patterns all have been contributing to the loss of endorheic lakes as well, and climate change's contribution to the problem is only going to get worse over time.

Lake Urmia in Iran was once the largest saltwater lake in the Middle East, but has shrunk over 80% in the past 30 years. Salt dust storms now originate from the wide expanse of dried lakebed revealed this wway, causing major health problems in the nearby city of Tabriz (population 1.5 million). Its gorgeous blue waters have been stained blood red by bacteria and algae that have been thriving in the increased salinity of the remaining water. [Image source]

While endorheic lake loss isn't exactly the most glamorous environmental issue, and doesn't get a lot of attention from the public, governments worldwide are very, very much aware of the issue, even to the point of cooperating with nominal enemies. The United States and Iran have been cooperating on studying effective ways to preserve these lakes, since both nations have important endorheic lakes at risk. (The Salton Sea, the Great Salt Lake, Owens Lake, Mono Lake, and more in America, while Lake Urmia is the main lake at threat in Iran.)

As with so many environmental threats facing the planet today, especially climate change related threats, indigenous peoples are often the first and the most severely affected. Indigenous peoples, being so often dependent upon local food sources from subsistence hunting, fishing, and gathering, are much more sensitive to environmental damage to those regions. While most individual groups of indigenous peoples are small, there are a surprisingly high number of different groups remaining, and have contributed heavily (by proportion of their population) to the ongoing environmental refugee crisis. The global poor in general are extremely vulnerable to environmental crises, for a wide variety of reasons- mostly similar to the reason that they're more vulnerable to any crises.

Fucine Lake was a large endorheic lake in central Italy. It was once the third largest lake in Italy, but was deliberately drained in 1877. The resulting land has proved to be extremely fertile cropland. Fucine Lake is one of the few cases where the draining of an endorheic lake has turned out well for the local community, if not for the local ecosystems. [Image source]

In 2016 alone 23.5 million people fled their homes because of weather disasters, including floods, wildfires, extreme temperatures, and more. This drastically outnumbers the 6.9 million forced to leave their homes due to war and violence. That 23.5 million figure, however, leaves out non-disaster related environmental refugees- victims of droughts and other gradual environmental damage. Since they aren't fleeing violence or persecution, they don't earn UN refugee status and protections when they cross borders, making this refugee crises a severe one- indeed, some of the most pressing concerns, both practical and ethical, for richer nations better able to cope with environmental crises will result from these refugee movements.

The ongoing endorheic lake drying crisis is a symptom of quite a few maladaptive strategies of human civilization. We've systematically expanded into marginal regions, overstressing and often completely overwhelming the biological carrying capacity of the region. Two and a half billion people now live in places where human water needs now exceed the supply available, both due to human expansion and decreased accessibility. We've also rapidly pushed forward not only settlement in these regions, but agriculture and industry as well. Simply speaking, we tried to farm everywhere, and it turns out that only a relatively moderate amount of the Earth's land is viable for long-term agriculture. Expanding beyond that has resulted in extensive environmental damage. Ultimately, these crises can only be addressed by our civilization learning to think seriously about the future in a way that it has consistently failed to thus far. Short term gains are still prioritized over all else by far too many governments, corporations, and individuals, and so long as they do so they will continue to perpetuate these environmental crises.

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Bibliography:

• The Climate Casino, by William Nordhaus
  -Cadillac Desert, by Marc Reisner
• https://www.nationalgeographic.com/magazine/2018/03/drying-lakes-climate-change-global-warming-drought/
  https://link.springer.com/chapter/10.1007/978-94-007-0967-6_1
• https://en.wikipedia.org/wiki/Endorheic_basin
• https://en.wikipedia.org/wiki/Sink_(geography)
• https://en.wikipedia.org/wiki/Lake_Chad
• https://en.wikipedia.org/wiki/Dead_Sea
• https://en.wikipedia.org/wiki/Red_Sea%E2%80%93Dead_Sea_Water_Conveyance
• https://en.wikipedia.org/wiki/Lake_Urmia
• https://en.wikipedia.org/wiki/Karst
• https://en.wikipedia.org/wiki/Fucine_Lake
• https://en.wikipedia.org/wiki/List_of_drying_lakes