1 . When 62-year-old fisherman Kpana Charlie has finished placing the day’s catch in his nets, he likes to sit on his wooden chair and let his mind go back to his childhood. Back then, his home on Sierra Leone’s Nyangai Island seemed like a paradise (天堂).

He spent endless hours playing with his friends on the island’s shining white beaches. He liked to kick around a soccer ball on the sports field in his village, and in mango season, he would shake the trees to collect their colorful fruit. Whenever he wanted to avoid doing his homework, he could simply disappear into the thick forest that covered much of the island.

Today, Nyangai is disappearing, swallowed up by the sea. As recently as ten years ago, it still measured some 2, 300 feet from end to end. What’s left today is a patch of (一片) sand which is 300 feet long and 250 wide. The forests are gone, flooded by saltwater. The soccer field lies under water for 22 hours of the day. And the land on which Charlie’s family home once stood, the home he was born in, has been disappearing under the waves. In as little as two years, Charlie fears, Nyangai may no longer exist at all.

With nearly a third of its population living in coastal areas, and its heavy reliance on agriculture and fishing, Sierra Leone has been treated as one of the world’s most vulnerable countries to the effects of climate (气候) change.

Gabriel Jaka, head of operations for the country’s Meteorological Agency, says the reason for Nyangai’s troubles is clear. “We’re seeing a significant sea-level rise and these people don’t have any proper defenses,” he says. “All they have are sandbags. If we don’t act now, the effects on people are just going to get worse.”

3 . More than 80 percent of global heat is absorbed by the ocean, which has a massive capacity to store and give off heat. High sea-surface temperatures are causing long-term damage to coral reefs (珊瑚礁). Corals are dying. The IPCC (政府间气候变化专门委员会) projects that up to 90 percent of coral reefs could disappear if global warming reaches 1.5℃. Another reason corals are in trouble is because of ocean acidification. Higher carbon dioxide levels have shift ed the chemistry of the ocean, making it more acidic, and corals and sea creatures have trouble growing in acidic conditions.

When ocean water warms, it expands in volume. This is a major cause of the rise in sea levels, along with the water added to the ocean by the melting of land-based glaciers (冰川). The sea level has risen by an average of 20 centimeters since the late 19th century, and the research by scientists studying the last 25 years of satellite data found that the ocean water is rising faster and faster. If it continues at its current rate, the rise in sea level by 2100 will be more than double the current estimates. Sea level rise leads to the destruction of coastal wetlands, flooding and damage to water ecosystems.

Temperature and precipitation (沉淀) are key elements of climate. A warmer climate means that more water rises from both the land and ocean, and a warmer atmosphere holds more of that water. Scientists have noticed that there are more heavy rainfall events. Additionally, higher water temperature in streams, lakes, and rivers lead to lower levels of dissolved oxygen in the water, which impacts the survival and populations of fish and other sea life.

Especially troubling are the extreme weather events that are happening more often around the world. Hurricanes are ramping up in intensity, particularly in North Atlantic. The year 2017 was a busy one for Atlantic hurricanes. Meanwhile, in the western United States, the state of California has had record-setting drought conditions, which began in 2012.

4 . Researchers and environmentalists have been pushing for clean energy, as well, contending with the rising threat of climate change. An increasingly researched renewable resource is called Ocean Thermal Energy Conversion (OTEC), in which the sea’s temperature variations are used to produce power. On the surface of the ocean, the temperatures are much warmer compared to the seafloor. It gets considerably colder the deeper you go because the sunlight cannot reach the bottom. These temperature differences are most noticeable in the summer when the sun is present for a majority of the hours of the day. To put it simply, OTEC uses a series of pipes that take the cooler water out in the depths of the ocean. The warm water on the ocean’s surface helps heat the cool water, which then vaporizes (蒸发) a fluid, and as a result, turns a turbine (涡轮机) to produce electricity.

Three types of ocean heat renewable energy systems are being developed and researched. An OTEC closed-cycle is perhaps the most common and well-researched, consisting of a condenser (冷凝器), evaporator, pumps, turbine and generator. There are also open systems and hybrid systems.

Systems work by pumping the warmer surface water through an evaporator containing a working fluid with a low boiling point, such as ammonia. Once the fluid vaporizes, it is used to drive a turbine and generator. From there, the vaporized fluid turns back into a liquid through a condenser, cooled by the cold, deep ocean water that pumps up from the depths. The OTEC systems that use seawater can use condensation to make water without salt.

OTEC systems need to place technology about 1 kilometer below the surface of the water. The cold water intake pipe is in the deepest area, and the piping where warm water enters is above sea level. The pumps are needed to move warm water into the system, and a heat exchanger is required to evaporate the fluid. Condensers condense the steam produced in the system, and a marker keeps the entire system afloat.

Energy is essential for almost all human activities. If the world wants to avoid an energy crisis, people need to begin relying on renewable energy. Fortunately, the three types of OTEC can provide energy for large populations.

5 . You may not be able to change your school’s environmental policy, but you can be the change you want to see in the world. Going eco-friendly can raise awareness of environmental issues. Here are some ways that can help you go green.

Take notes electronically

    1    ? Use a digital device such as a laptop or table t to take your notes. This will stop paper waste and also save you a ton of money! In case you don’t have a tablet or laptop, purchase a budget-friendly device.     2    . And there are lots of devices to choose from that will do just fine for note-taking, research, and so on.

Embrace (拥抱) recycling

How many soft drink cans, papers from lecture notes, plastic water bottles, and snack food packaging does every high-school student throw away? More than we could count!     3    . Focus your attention on recycling. Most areas have curbside recycling, so make sure that you place the recycled waste in the right bin.

    4    

The emission of air pollutants from transport is one of the biggest enemies of a healthy environment. To reduce the environmental impact of transport and improve public health, use sustainable (可持续的) transport. Switch from car rides to riding a bike. Also, if you are hanging out with your friends nearby, take a walk. In addition to reducing air pollution, you’ll also keep your body healthy.

Eat some greens

You don’t have to turn into a vegetarian, but you might want to consider increasing your greens. Vegetarian meals are good for your health, and they have a lower carbon footprint. Start off by introducing a meat-free day once a week. If you don’t mind getting your hands dirty, think about growing your own fruits and vegetables.     5    .

Should we explore the sea?

7 . To reach a sustainable food system, “integrity has to run through the whole system, especially with the farmers,” say Jan and Steve Petersen, Niman Ranch farmers. “We have to learn to care for our shared resources, like soil, water, air, and ecosystems.”

Jan and Steve created a family of sustainability advocates. To them, sustainable farming means protecting soil, water, and ecosystems for future generations. The Petersen family always farmed crops sustainably and raised their pigs naturally, using mostly organic practices. Their son Ted continues to work on the farm part-time, while their oldest son Luke works with farmers in California to encourage sustainable farming practices as a conservation biologist who received a Niman Ranch Next Generation Scholarship Award in 2008 to help him continue his farming practices. “He doesn’t hesitate to feed his dad ideas on new practices and technologies,” says Jan.

The Petersens joined Niman Ranch in 2003 for the support it provided for farmers raising pigs naturally after the pig market crashed in 1998. “We suddenly had a sense of belonging and support, becoming part of a whole network of farmers who shared similar values,” explain Jan and Steve. “This matched our personal passion for community revitalization (复兴) and the promotion of responsible land use practices.”

In their community, the Petersens have a great passion for responsible land use and its benefits for the food system. They realized early on how farmland preservation is connected to all sorts of land use issues, so they got involved on many levels. Steve chairs the local planning committee. And Jan not only started the community’s farmers’ market, but also serves on the county Brownfield Redevelopment Authority, encouraging businesses to redevelop ignored properties. Together, the Petersens also brought historic property in their community back to life.

“We feel we are caretakers of not just the land on this fifth generation farm, but also the historic house and barns, around 1871, here on the Petersen Farm. We always hope the wildlife appreciates our commitment to avoiding farming the whole place into the ground,” say the Petersens.

8 . Raising a litter of teething wolf pups (幼崽) is not easy, but the wolves living in Yellowstone National Park are parenting experts. This spring, the park’s biologists shot a video of adult wolves repeatedly returning to their den (窝) with so-called “toys”—in the form of bones and sticks—to keep their little ones happy between meals.

Once they stop eating their mother’s milk, pups rely on adults to go out, hunt, and then bring back food to the den. But when that’s not possible, the adults instead retrieve odd items for the wolf pups to play with.

“Pups wait for food deliveries from successful hunts, but in the absence of food, adults bring ‘toys’,” the park wrote on Facebook. “The behavior of bringing items back to the den may be enhanced from generation to generation and probably helps keep adults from being surrounded by sharp puppy teeth.”

The adult wolves are part of “Mollie’s Pack”, one of ten known wolf packs living within Yellowstone as of January 2023. This particular pack is named after Mollie Beattie, who in 1993 became the first woman to serve as director of the United States Fish and Wildlife Service.

Beattie, who died in 1996, advocated for the reintroduction of wolves into Yellowstone National Park to help rebalance the ecosystem after the animals were systematically killed within the park Wolf reintroduction was a highly controversial initiative that many people opposed. And yet, Beattie and other wildlife managers ultimately achieved their vision and successfully relocated 41 wolves from western Canada to the park between 1995 and 1997. Today, that number has blossomed to at least 108 wolves living in Yellowstone.

Today, gray wolves are protected under the Endangered Species Act in many states. In late 2020, the administration removed the animals from the endangered list. But in February 2022, they were re-listed as endangered after a judge reversed the decision.