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River deltas are ‘drowning’, threatening hundreds of millions of people

The world’s river deltas take up less than 0.5% of the global land area, but they are home to hundreds of millions of people. Many live in major fast-growing cities such as Kolkata in the Ganges delta, Bangkok in the Chao Phraya delta, or Shanghai, one of dozens of large cities in the Yangtze delta region.

With fertile soils and easy access to the coast, deltas are critical hotspots of food production. Vietnam’s Mekong delta alone supplies almost 20% of the world’s rice. They also host unique ecosystems such as the Sundarbans in Bangladesh and India, the largest mangrove forest in the world.

But many of the world’s deltas are now facing an existential crisis. Sea levels are rising as a result of climate change, while deltas are themselves sinking, and together this means the relative sea level is rising extra fast.

Deltas are built from sediments that are carried downstream by rivers and eventually deposited where the river meets the sea. As these sediments compact under their own weight, deltas naturally sink. Where left undisturbed, the supply of new river sediment can compensate for the subsidence and help to maintain the delta surface above sea level.

But deltas are now subsiding much faster than they would do naturally. That’s thanks to groundwater being pumped (or “mined”) from aquifers underneath them and used to irrigate crops and provide water for rapidly growing cities.

In these circumstances, only the continued deposition of sediment on deltas can keep them from “drowning”. We therefore wanted to find out whether supplies of river sediments would be affected by future environmental changes.

To address this question, we used a computer model to project changes in the flows of sediment to almost 50 major deltas worldwide. We used the model to explore the impact of various environmental changes, including climate change, population growth, increases in wealth and the construction of dams. Our results are published in the journal Environmental Research Letters.

Rice farmers in the Mekong Delta, Vietnam.
Phuong D. Nguyen / shutterstock

We found that most of the world’s major deltas will receive less river sediment by the end of the century, regardless of the environmental change scenario. On average, we projected a 38% decrease. Our results suggest that many deltas – already significantly stressed – will become sediment starved, further compounding the risks of rising relative sea levels.

Some of the most severe reductions will be found in major Asian deltas such as the Ganges (81% less sediment) and the Mekong (77%). This is particularly concerning because these deltas are among the largest and most densely populated in the world.

We found that climate change will generally drive a small increase in the flows of sediments as, among other factors, warmer temperatures lead to increased precipitation and more soil is washed into rivers. But in many deltas this modest uptick will be more than offset by dams (which trap river sediments) and improved soil conservation practices as societies become wealthier. The Aswan Dam on the River Nile in Egypt or the Hoover Dam on the Colorado River in the US are among the dams that have already starved their downstream deltas of sediment.

Bad news for a river delta.
Tupungato / shutterstock

Better management of river sediment is vital to improve the outlook for the world’s deltas. International cooperation will be essential in deltas such as the Mekong and Ganges which are supplied by large rivers that drain many countries. For dams specifically, comprehensive environmental risk assessments that fully cost the consequences for downstream regions are required so that plans can be changed or scrapped. For those dams that are to be built in the coming decades, their design must accommodate transport of sediment downstream.

For authorities within deltas, faced with managing a dwindling supply of river sediment, new approaches are needed to better manage this precious declining resource. Flood embankments prevent sediment reaching delta plains and may need to be breached, as is being explored in the Ganges delta. Additionally, the removal of sand from rivers for construction materials, which is pervasive in many deltas around the world, must be better managed.

Ultimately, difficult decisions need to be made about development priorities between countries upstream of deltas and those including the deltas themselves, and there will be trade-offs to be made between hydropower, agricultural practices and delta sustainability.

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Planet Earth

A tourist fell into a fire trap: published a creepy video from California

The video, which was filmed in the Sierra National Forest, located in California, shows how one of the holidaymakers was in the heart of a fire trap.

This vacationer turned out to be just one person out of 207 who were also captured in the fire and were saved in the very last moments. The rescue service came to their aid, which took people to a safe place. 

In the video, which was made by a man on the estate of Jeremy Remington, you can clearly see how cars burn, and the flame is getting closer to tourists and its speed is noticeably increasing.

People were in a real trap. Fire surrounded them on all sides, and the roads that could be driven were destroyed. According to the information provided by the Emergency Situations Department, work to rescue tourists began on Saturday evening and continued until Sunday morning. 

More than 20 people had to be transported to hospitals. Two of the victims were in critical condition and required immediate medical attention. At the same time, two people who were vacationing in the National Forest refused the proposed evacuation.

The scale of the wildfire that started on Friday is not too large. But at the same time, the fire managed to destroy more than 71 square miles of forest. By the middle of Saturday, due to the increase in the rate of spread of fire, a 7 times larger area was destroyed. 

On Sunday morning, it was possible to stop the fire by no more than 5%, so the work continued actively and further.

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Planet Earth

Great solar minimum and the onset of the Little Ice Age

Niels-Axel Mörner is the former head of the Department of Paleogeophysics and Geodynamics at Stockholm University. He retired in 2005 and has since dedicated his days to refuting the global warming bullshit as well as warning of an impending Great Solar Minimum.

From 1997 to 2003, Moerner led the INTAS project on geomagnetism and climate. The project concluded that in the middle of the 21st century we should return to a new solar minimum with climatic conditions of the Little Ice Age.

In 2015, Moerner’s study “Approaching New Great Solar Minimum and Climatic Conditions of the Little Ice Age” was published. 

The conclusions are that by 2030–2040 the Sun will experience a new large solar minimum. 

During the previous large solar minima – the Sperer Minimum (1440-1460), the Maunder Minimum (1687-1703), and the Dalton Minimum (1809-1821) – climatic conditions worsened and the Little Ice Age began.

During the last three large solar minimums – the Sperer, Maunder and Dalton minimums – the global climate has experienced Little Ice Age conditions. Arctic waters penetrated south as far as Central Portugal and Europe experienced harsh climatic conditions. The ice cover of the Arctic has expanded significantly.

We now have data indicating that by 2030-2040. A New Great Solar Minimum will come, which, by analogy with past minimums, will lead to a significant deterioration of the climate with the expansion of ice in the Arctic and global cooling.

All this excludes the theory of global warming, instead of warming, we will face a new Little Ice Age .

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Planet Earth

California wildfires create giant “volcanic” clouds

California is now burning like hell and fires are creating huge pyrocumulus clouds as a result of intense heating of the air from the surface. 

The heat from the fires spreads so much that it creates its own pyrocumulus cloud systems, each up to 9 km high. These clouds make fire fighting very difficult. 

The intense heat causes convection, which causes the air mass to rise very high, causing apocalyptic clouds.

Common clouds form when the sun heats up the earth’s surface, causing water to evaporate and rise into the atmosphere, where it cools and condenses into a cloud.

This is a relatively slow process compared to the formation of a pyrocumulus cloud, when the intense heat of a huge forest fire burns moisture from vegetation. Then this moisture accumulates on the smoke particles and quickly condenses, rising up. 

Pyrocumulus clouds are more commonly seen over volcanic eruptions, which produce a lot of steam. If you’ve ever seen an ominous cloud creating dry lightning over a volcano, then this is a pyrocumulus cloud. They are black or dark brown due to volcanic ash, and those from wildfires are usually dark gray due to smoke and ash.

The rate at which pyrocumulus clouds form and change, combined with the heat from the fire, can lead to rapid and severe temperature fluctuations in the atmosphere, causing unpredictable and high winds.

They can exacerbate the intensity of forest fires and cause them to move or otherwise behave in unpredictable ways. And all this can endanger the lives of firefighters and people. 

However, if the fire is large enough, the cloud can continue to grow and turn into a cumulonimbus cloud, which can cause powerful thunderstorm activity, and lightning in turn can trigger another fire. 

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