Light pollution is a significant but overlooked driver of the rapid decline of insect populations, according to the most comprehensive review of the scientific evidence to date.

Artificial light at night can affect every aspect of insects' lives, the researchers said. "We strongly believe artificial light at night — in combination with habitat loss, chemical pollution.invasive (入侵的) species, and climate change — is driving insect declines, " the scientists concluded after assessing more than 150 studies.

Insect population collapses have been reported around the world, and the first global scientific review published in February, said widespread declines threatened to cause a "catastrophic collapse of nature's ecosystems".

There are thought to be millions of insect species, most still unknown to science, and about half are active at night. Those active in the day may also be disturbed by light at night when they are at rest.

The most familiar impact of light pollution is moths (飞蛾) flapping around a bulb, mistaking it for the moon. Some insects use the polarisation of light to find the water they need to breed, as light waves line up after reflecting from a smooth surface. But artificial light can scupper (使泡汤) this. Insects are important prey (猎物) for many species, but light pollution can tip the balance in favour of the predator if it traps insects around lights. Such increases in predation risk were likely to cause the rapid extinction of affected species, the researchers said.

The researchers said most human-caused threats to insects have analogues in nature, such as climate change and invasive species. But light pollution is particularly hard for insects to deal with.

However, unlike other drivers of decline, light pollution is relatively easy to prevent. Simply turning off lights that are not needed is the most obvious action, he said, while making lights motion-activated also cuts light pollution. Shading lights so only the area needed is lit up is important. It is the same with avoiding blue-white lights, which interfere with daily rhythms. LED lights also offer hope as they can be easily tuned to avoid harmful colours and flicker rates.

Vast underwater meadows (草甸) of gently waving sea grass cover hundreds of miles up and down the West Coast. These blue-green fields perform a variety of important services. They protect the shoreline from erosion, clear pollutants from the water and provide habitats for all kinds of marine animals.

New research suggests sea grass meadows may also mitigate a serious consequence of greenhouse gas emissions: the steady acidification of ocean waters. The study published in the journal Global Change Biology finds that sea grass forests can raise pH levels in coastal waters. As they perform photosynthesis (光合作用), they remove carbon dioxide from the water, counteracting the acidifying effect of the gas.

“I think we are all very excited about it,” said lead study author Aurora Ricart, a scientist at the Bigelow Laboratory for Marine Sciences.

Ocean acidification is a side effect of rising carbon dioxide levels in the atmosphere. Some of this CO₂ dissolves out of the air and into the sea, causing a chemical reaction that lowers the water’s pH. Scientists sometimes refer to it as global warming’s “evil twin”—an invisible companion to climate change.

Ocean acidification can have harmful effects on marine organisms like shellfish and coral by preventing them from properly forming the hard shells they need to survive. It’s a threat both to natural ecosystems and to shellfish fisheries around the world. The study presents a natural way to address the problem.

Researchers analyzed six years of data from sea grass meadows spanning more than 600 miles off the California coastline. It focused on the common eelgrass, one of the most widespread sea grass species on the West Coast. The authors claim it’s the largest, most comprehensive study of its kind.

According to the study, sea grass ecosystems can raise pH levels by more than 0.1 unit, equivalent to about a 30% decrease in acidity. The effect isn’t constant. It comes in waves and is influenced by temperature, daylight, ocean currents and other factors that affect water chemistry and sea grass photosynthesis rates. But the tempering influence on acidification can be lasting, sometimes persisting for up to three weeks at a time. The study also shows that pH is higher in sea grass ecosystems, compared to nearby areas with no sea grass, about 65% of the time.

The study didn’t investigate the effects of higher pH on marine organisms — that’s a question for future research. But there’s reason to believe these meadows may have a positive influence on shellfish and other ocean animals.

King Canute couldn’t stop the ocean’s tide from rolling in — can Africa hold back the desert?That’s certainly what the continent is tying to do with its proposed “Great Green Wall”, 800km (almost 5,00 miles) worth of trees that officials hope will stop the advancement of the Sahara Desert, which has been rapidly expanding southward.

The idea was introduced in the 1970s when the once-rich region turned barren (贫瘠的) due to climate change and intensive land use. But it’s not a new idea; China has its own desert vegetation project to hold back the Gobi Desert! Thanks to the Chinese plan, the African project aims to plant 100 million hectares of trees by 2030 across the entire Africa. The initiative is a decade in, and around 15% completed, and there have already been benefits for many communities and wildlife. It’s bringing life back to the continent’s degraded landscapes at an unprecedented scale, providing not only food security and jobs but a reason to stay for the millions who live along its path.

The creators of the wall hope it will bring an urgently needed solution to the threats facing the African continent, creating 10 million jobs in rural areas, as well as preventing 250 million tons of carbon. The initiative is Africa-driven, which for those on the continent, is vital, and may hold the key to success. “The Great Green Wall…is about ownership, and that has been the failure of development aid because people were never identified with it,” said Elvis Paul Tangam, African Union Commissioner for the Sahara and Sahel Great Green Wall Initiative.“But this time they identify. This is the very thing of us!”

The wall may seem like a moonshot, but all the best ideas usually are. As Thomas Sankara, former president of Burkina Faso said in 1985, “You cannot carry out fundamental change without a certain degree of madness. The courage to turn your back on the old formulas, the courage to invent the future.”