1 . For uncounted generations, trillions of coral polyps (珊瑚虫) have lived and died, leaving behind a material called limestone. Throughout History, limestone was used to construct the Great Pyramid of Egypt, as well as many churches and castles.       1    . We can call them reefs (礁体). They can be even larger in scale than the most impressive buildings and structures made by humans.

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Indeed, a living coral reef is remarkable, a “city beneath the sea” filled with a rich variety of life. Most coral reefs can be found in warm, shallow oceans. They occupy just a small part of the ocean floor, but host 25 percent of all ocean life. Each reef is full of colorful fish as well as coral that forms wonderful patterns. In addition to their beauty, the reefs are an important food source for fish, and for. humans.

Threats to coral reefs

    3    . For example, reefs can be damaged when the coral is taken for use in building materials or jewelry-making. Illegal fishing methods also harm reefs. These methods can help fishermen get a good catch, but their negative effects on the reefs are significant. Blast fishing involves setting off bombs in the water to kill as many fish as possible.     4     In addition, global warming has caused many reefs to become sick. A 2018 UN Report predicted that up to 99 percent of the world’s coral reefs may decline if global warming continues.   

Reasons for hope

These threats to coral reefs are very serious, but there is reason to hope that they will survive. If we take steps toward coral reef conservation, it is likely that these tiny creatures — which survived natural threats for millions of years — will be able to rebuild. As conservationist Robert Richmond says, “    5    . ”

2 . Whales are celebrated for being the largest and most intelligent creatures in the ocean. Now, biologists have discovered that they also capture (捕获) tons of carbon from the atmosphere, a service with an economic value of US $1 trillion for all the great whales, according to a new study published by the International Monetary Fund. The study points out that protecting whales, normally viewed as a human good, also has a monetary motivation.

“The carbon capture potential of whales is truly incredible,” said the report. “Our conservative estimates put the value of the average great whale at more than US $2 million, and easily over US $1 trillion for the current stock of great whales.” Whales absorb carbon in their bodies during their long lives, some of which stretch to 200 years. When they die, they sink to the bottom of the ocean, taking the carbon with them. According to the study, each great whale traps around 33 tons of carbon dioxide on average. A tree during the same period only contributes to 3 percent of the carbon absorption of the whale.

Whale populations are today a smidgen of what they once were. It is estimated that there are slightly more than 1.3 million whales in the ocean, a quarter of their pre-whaling number of 4 to 5 million. Some species in particular, like the blue whale, are only 3 percent of what they used to be. “We can create financial methods to promote the restoration of the world’s whale populations,” said the report’s authors. “Rewards could help those who pay significant costs as a result of whale protection.”

With the Paris Agreement coming into force next year and the effects of climate change ever more widespread, we must prevent the harm to whales. Researchers analyzed that unless new methods are put forward, it would take over 30 years to double the number of current whales, and several generations to return them to their pre-whaling numbers. “Society and our own survival can’t afford to wait this long,” they said.

4 . Despite the difficulties, the California coastal ecosystem is improving, largely thanks to the huge appetite sea otters (海獭) have for crabs. In a creative study, scientists revealed the return of otters to their former habitat in a Central California river mouth has slowed the decrease of the area’s river banks by up to 90%. “It would cost tens of millions of dollars for humans to rebuild these stream banks and restore these rivers. The otters are stabilizing them for free, in exchange for an all-you-can-eat crab feast,” said biology professor Brian Silliman, Ph. D. at Duke University.

Like many California river mouths, Elkhorn once was a habitat for otters, which need to eat around 20 to 25 pounds of food every day, with crabs being one of their favorite meals. But after fur traders hunted the local otter population nearly to extinction, the number of crabs exploded over the next century. Crabs dig into salt river soil, and over time can cause a salt river to wear away and collapse. Today, years after the otters returned, rivers and stream banks became more stable.

Angelini, one of the study’s authors, said that tool is an encouraging sign for her team as they face similar threats to Florida’s coastlines from sea level rise, storms, and extra nutrients overflowing into coastal waters. “All these seem unsurmountable,” Angelini said. “However, this study shows that, if we truly understand the ecosystem and know what tools to use, we can see significant benefits to the health and stability of these systems.”

The research team conducted large-scale surveys across 13 tidal (潮汐的) streams, as well as small-scale field experiments at five locations around the river mouth over a six-year period. Otters were not included in some lest sites but allowed to be used in others, using a caging system designed by Angelini.

“And all these years later, we now see these amazing results. It’s an inspiring story about the benefits of conservation and persistent, long-term research,” Angelini said.

5 . Google recently announced that it has begun using carbon-free electricity from a geothermal (地热能) project to power data centers in the state of Nevada.

Tim Latimer is chief and co-founder of Fervo Energy based in Houston, Texas. His company is working with Google on its geothermal project. Latimer said that getting electricity on the grid from geothermal resources is an event many new energy companies never reach. He added that he believes geothermal energy will become more well-known than in the past.

The International Energy Agency(IEA) has long suggested geothermal could be an answer to climate change. The IEA said in a 2011 document that geothermal could reach 3.5 percent of global electricity production each year by 2050. The Paris-based international group says geothermal energy could prevent almost 800 million tonnes of carbon dioxide emissions per year.

Fervo Energy is using this first test to launch other projects that will provide more electricity to the grid. The company is currently completing some work in southwest Utah for a 400-megawatt project. Google and Fervo Energy started working together in 2021 to develop geothermal power. The plant near Winnemucca, Nevada, is now operating and is sending about 3.5 megawatts to the grid.

Google announced in 2020 that it would use what it calls “carbon-free” energy every hour of every day, wherever it operates, by 2030. Many energy experts believe huge companies like Google can play a part in increasing the use of clean energy.

Terrell noted the company was also an early supporter of wind and solar projects, helping those markets grow to where they are today. “It’s a very similar situation. Now that we’ve set a goal to be 24/7 carbon-free energy, we have found it will take more than just wind, solar and storage,” Terrell said.

The United States leads the world in using heat from the Earth for electricity production. U. S. Energy Secretary Jennifer Granholm said earlier this year that advances in new geothermal systems will help introduce this form of energy to areas where it has been thought to be impossible. This makes it possible to find energy in more places.

7 . The biggest risk to UK forests over the next 50 years is a “catastrophic” collapse of their ecosystems, according to a group of experts. The group of 42 researchers were asked to identify the issues that would have the greatest impact on UK forests in the next half-century. The list was topped by “catastrophic forest ecosystem collapse”, the prospect of a number of risks, from droughts and floods to storms and pests. If action is not taken, the ecosystem will no longer function effectively.

This is the first “horizon scanning” exercise — a technique to identify relatively unknown threats, opportunities, and new trends — of UK forests. The aim is to help researchers, practitioners, policymakers, and society in general, better prepare for the future and address threats before they become critical.

Experts define such a collapse as a “sudden, long-lasting and widespread change in ecosystem state that has major negative impacts on biodiversity and key ecosystem services”. Those ecosystem services include clean air and water. Some species could be pushed to extinction. “Forest collapse will have significant short-and long-term influences on the forest, and wider environment, economy and society,” the researchers said.

The UK is one of the least forested countries in Europe, with 13 percent of land being forested, compared with a European average of 46 percent. The government has a UK tree-planting goal of 30,000 hectares by 2025, but is widely expected to miss it.

A spokesman for the Department for Environment said,“ We will continue to work with partners to tackle the challenges and opportunities raised in today’s report to ensure our trees and woodlands remain healthy, so they can support habitats and a range of wider environmental benefits.”

The Times revealed this year that more than 400,000 trees planted in England to make up for road projects had died since 2018. Experts think an increase in dry spring s and hot summers has made tree aftercare harder.

8 . Profits from cutting down rainforests are surprisingly small. A freshly cleared square kilometer of the Amazon rainforest fetches an average price of only around $ 12. By contrast, the social costs of clearing it are huge. Some 500 tons of carbon dioxide are pumped into the atmosphere. By an estimate, that does $ 25,000 of harm by accelerating climate change.

Yet still the world’s trees are disappearing. The senseless men cutting down trees receive the profits, but all 8 billion people on the planet pay for the costs. Clearly, if the owners of the rainforest were paid not to destroy it, everyone would be better off. If rainforests were in places with clear landownership and a firm rule of law, the world would no doubt already have funded such a deal. Sadly, they are not.

Local officials are often in league with the loggers, and may be loggers themselves. Consider Brazil. It had a leader, who sided with illegal loggers and ranchers (大农场主). He stopped fining forest criminals and told illegal miners on local reserves he would legalise the mining. On his watch the pace of deforestation rose by 60%. Local communities often refuse to follow the law and order since they see more benefit from deforestation than protecting it. And the land ownership is a mess. When it’s unclear who owns a piece of land, it’s unclear whom to pay to protect it, or whom to fine for destroying it.

Leadership matters. But even under better leaders, people living there should see benefits in protecting them. That will require a big, reliable flow of cash which should come from rich-country governments and from private firms buying carbon credits to make up for their emissions (排放).

Such carbon credits could be used to promote a greener local economy, and clean up local land registration. If there’s enough cash, conditionally paid, locals will be encouraged to protect trees and less likely to elect irresponsible leaders. To preserve such a huge carbon sink — never mind the biodiversity it contains — this would be a bargain.

10 . Landfills are places where a large amount of waste and other refuse is buried in the ground. They are responsible for releasing a large amount of planet-warming methane gas into the atmosphere, a new study suggests.

The study, which was published in Science Advances on Wednesday, is aimed at helping local governments carry out targeted efforts to limit global warming by identifying areas of major concern. For this purpose, the scientists used satellite data from four major cities around the world — Delhi and Mumbai in India, Lahore in Pakistan and Buenos Aires in Argentina.

Based on the collected data, the scientists have drawn the conclusion that landfills are the third-largest source of methane emissions (排放) worldwide, after oil and gas systems and agriculture. And further investigation shows that the methane released from the landfills is generated from the decomposition (分解) of natural waste in them, like food, wood or paper.

Methane, though only accounting for about 11 percent of greenhouse gas emissions, traps 80 times more heat in the atmosphere than CO₂. Scientists estimate that at least 25 percent of today’s warming is driven by methane from human actions. That’s why landfills are partly to blame for the global warming.

Joannes Maasakkers, a leader of the study, said, “We found that these landfills, which are relatively small compared to city sizes, are responsible for a large part of total emissions from a given area.” Another scientist, Euan Nisbet, who was not part of the study, said, “This new work shows just how important it is to manage landfills better, especially in countries like India where landfills are often on fire, resulting in a wide range of damaging pollutants (污染物).” He also added that the newer satellite technology and on-the-ground research make it easier for researchers to identify “who is polluting the world”.