Science

Like so many of the planet’s natural habitats, wetlands have been systematically destroyed over the past 300 years. Bogs, fens, marshes and swamps have disappeared from maps and memory, having been drained, dug up and built on.

Being close to a reliable source of water and generally flat, wetlands were always prime targets for building towns and farms. Draining their waterlogged soils has produced some of the most fertile farmland available.

But wetlands also offer some of the best natural solutions to modern crises. They can clean water by removing and filtering pollutants, displace floodwater, shelter wildlife, improve our mental and physical wellbeing and capture climate-changing amounts of carbon.

Peatlands, a particular type of wetland, store at least twice the carbon of all the world’s forests.

How much of the Earth’s precious wetlands have been lost since 1700 was recently addressed by a major new study published in Nature. Previously, it was feared that as much as 50% of our wetlands might have been wiped out. However, the latest research suggests that the figure is actually closer to 21% - an area the size of India.

Some countries have seen much higher losses, with Ireland losing more than 90% of its wetlands. The main reason for these global losses has been the drainage of wetlands for growing crops.

A wetland is, like this peat bog, a terrestrial habitat where water is held on the land. Kuttelvaserova Stuchelova/Shutterstock

Wetlands are not wastelands

This is the most thorough investigation of its kind. The researchers used historical records and the latest maps to monitor land use on a global scale.

Despite this, the new paper highlights some of the scientific and cultural barriers to studying and managing wetlands. For instance, even identifying what is and isn’t a wetland is harder than for other habitats.

The defining characteristic of a wetland – being wet – is not always easily identified in each region and season. How much is the right amount of wetness? Some classification systems list coral reefs as wetlands, while others argue this is too wet.

And for centuries, wetlands were seen as unproductive wastelands ripe for converting to cropland. This makes records of where these ecosystems used to be sketchy at best.

The report shows clearly that the removal of wetlands is not spread evenly around the globe. Some regions have lost more than average. Around half of the wetlands in Europe have gone, with the UK losing 75% of its original area.

The US, central Asia, India, China, Japan and south-east Asia are also reported to have lost 50% of their original wetlands. It is these regional differences which promoted the idea that half of all the world’s wetlands had disappeared.

Farming has driven the destruction of wetlands globally. Tridsanu Thopet/Shutterstock

This disparity is somewhat hopeful, as it suggests there are still plenty of wetlands which haven’t been destroyed – particularly the vast northern peatlands of Siberia and Canada.

An ecological tonic

Losing a wetland a few acres in size may not sound much on a global or even national scale, but it’s very serious for the nearby town that now floods when it rains and is catastrophic for the specialised animals and plants, like curlews and swallowtail butterflies, living there.

Wetlands offer food and habitat for a diverse range of species. Aleksandra Tokarz/Shutterstock

Fortunately, countries and international organisations are beginning to understand how important wetlands are locally and globally, with some adopting “no-net-loss” policies that oblige developers to restore any habitats they destroy. The UK has promised to ban the sale of peat-based composts for amateur growers by 2024.

Wetland habitats are being conserved around the world, often at huge expense. Over US$10 billion (£8.2 billion) has been spent on a 35-year plan to restore the Florida Everglades, a unique network of subtropical wetlands, making it the largest and most expensive ecological restoration project in the world.

The creation of new wetlands is also underway in many places. The reintroduction of beavers to enclosures across Britain is expected to increase the nation’s wetland coverage, bringing with it all the advantages of these habitats.

Beaver dams and the wetlands they create reduce the effects of flooding by up to 60% and can boost the area’s wildlife. One study showed the number of local mammal species shot up by 86% thanks to these furry engineers.

Wetlands hold and slowly release water, helping to ease flooding and stall drought. Steved_np3/Shutterstock

Even the sustainable drainage system ponds developers create on the fringes of new housing estates could see pocket wetlands appearing in towns and cities across the UK. By mimicking natural drainage regimes instead of removing surface water with pipes and sewers, sustainable drainage systems can create areas of plants and water that have been shown to increase biodiversity, especially invertebrates.

Whether the total global loss of wetlands is 20% or 50% doesn’t really matter. What does matter is that people stop looking at wetlands as wastelands, there for us to drain and turn into “useful” land.

As the UN recently pointed out, an estimated 40% of Earth’s species live and breed in wetlands and a billion people depend on them for their livelihoods. Conserving and restoring these vital habitats is key to achieving a sustainable future.

Long-term exposure to air pollution raises the risk of depression, according to a pair of new studies published in the JAMA network of scientific journals.

A study published on Friday in JAMA Network Open found that long-term exposure to elevated levels of air pollution increases the risk of late-onset depression among the elderly.

Without stars, our universe would be a much darker, colder place. These balls of plasmic hydrogen and helium gas not only blast heat and light, they come in a stunning array of colors, chemical composition and size. And "big" doesn't begin to describe them. Our sun is 109 times larger than our planet. But our star isn't so special — it's technically average-sized. Some stars, like UY Scuti, an extreme red hypergiant in the constellation Scutum, have a radius 1,700 times our sun, which could fit inside it almost 5 billion times. Compared to UY Scuti, our favorite star is a speck of dust.

A group of US scientists this week proposed an unorthodox scheme to combat global warming: creating large clouds of Moon dust in space to reflect sunlight and cool the Earth.

In their plan, we would mine dust on the Moon and shoot it out towards the Sun. The dust would stay between the Sun and Earth for around a week, making sunlight around 2% dimmer at Earth’s surface, after which it would disperse and we would shoot out more dust.

This article originally appeared in the San Antonio Report.

SAN ANTONIO — Low-income and uninsured San Antonians will be most affected by the Biden administration’s decision to end the national COVID-19 emergency declarations on May 11.

The end of the national and public health emergencies means the end of federal support for COVID-19 resources, such as free vaccines and at-home tests. Many low-income residents will also be at risk of losing their Medicaid health insurance and food benefits.

There is a motion picture so scientifically irresponsible that merely mentioning its title instantly arouses ire in countless otherwise stolid academic personalities. When first released in 2003, it badly bombed at the box office, prompting one physicist to speculate that the public stayed away because it could smell garbage. It "did not make money because people understood the science was so out to lunch," Emory University Professor Sidney Perkowitz proclaimed at the time. Indeed, Perkowitz was so bothered by the movie's misinformation that he crafted a set of guidelines to help Hollywood studios avoid future embarrassments. Hundreds of fellow scientists expressed support for Perkowitz's position; today this movie is best remembered for helping inspire the creation of the Science & Entertainment Exchange, which promotes the use of better science in movies, television and other media.

"I got a call from the director who was in Hollywood and was upset at me because I had said these things. That's the point at which I realized that he thought that it was scientifically accurate!"

Minke whale excrement is "worth its weight in gold" as it plays an important role in fertilizing phytoplankton and thereby reducing the cetacean's carbon footprint, according to a Norwegian study.

For the first time, researchers from the Norwegian Institute for Marine Research have studied the concentration of nutrients in whale excrement before it is dissolved in seawater.