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.

5 . Catherine Krestyn furnished (布置家具)her home mainly with hard rubbish, such as the chairs, doors and lamps, which have been collected from the street where she lives. And it’s a way of life she’s sharing with her community in the hope of making a difference.

Catherine leads a 6,000-strong online group called Boroondara Hard Rubbish Rehome, where members upload pictures of their hard rubbish piles for eager locals to find. She started the group in 2022 with her childhood friend Jennie Irving, hoping to build a community of thrift (节俭)where they lived. The pair have stopped more than 7,000 kg of hard rubbish going to landfill since they founded the group.

Some items are ready as they are, like chairs and lamps, and others take a bit of effort to clean up, like the old, wooden doors.

Local teacher Ruth Polgar discovered the group while surfing the Internet and has since decorated her classroom with second-hand items, including artwork she has rehomed from a neighbour. “We regularly take unneeded items from the group and use them for our school projects,” she says.

Running the group can be really challenging for Catherine. But she doesn’t resent those who have to let go of their possessions because of stressful circumstances. “If you’re downsizing or if you’re clearing an old house, quite often you’re desperate for access to easy options,” she says. “Hard rubbish piles are often that option.”

All Catherine wants to do is give her community a way to reduce their waste, and to send a message to those in charge that things need to urgently change.

“The government has big targets around sustainable development leading into 2030. We want to start speeding that up even sooner,” she says. “We’re suffering from our own waste really, so anything that we can all do on a practical level helps. We should first make lifestyle choices and be prepared to go second-hand.”

6 . People have come to understand the enormous impacts-beneficial as well as harmful- plastics have on human lives and the environment. As polymer (聚合物) scientists committed to inventing sustainable solutions for real-world problems, we set out to tackle the issue of plastic waste by rethinking the way polymers are designed so we could make plastics with recyclability built right in.

Everyday items including milk jug, grocery bags, and takeout containers are made from a class of polymers called polyolefins. These plastics are really durable (耐用的) because the chemical bonds in those polymers are extremely stable. In a world set up for disposable (一次性的) items, durability is no longer a design feature but rather a design drawback. Imagine if half the plastics used today were recyclable through twice as many processes as they are now. Also conventional recycling requires careful sorting of all the collected materials, which can be challenging with so many different plastics. For example, separating paper from metal doesn’t require complex technology, but sorting a container from a milk jug of a different polyolefin is difficult to do without the occasional mistake.

In a study published in Science in October 2023, we described a series of polymers with only two building blocks-one soft polymer and one hard polymer-that behave like polyolefins but could be chemically recycled. Connecting two different polymers multiple times until they form a single, long molecule (分子) creates what’s called a multiblock polymer. By changing how much of each polymer type goes into the multiblock polymer, our team produced a wide range of materials with properties that covered all polyolefin types.

Using the same strategy but by adding hydrogen, we could disconnect the polymers back into their building blocks and easily separate them to use again. When we made new polymers out of these recycled plastics, they performed just as well as the original materials even after several rounds of chemical recycling. So we were able to create materials with similar properties of the plastics the world relies on. We believe this work is a step toward more sustainable plastics.

7 . Paris mayor Anne Hidalgo has long worked to make her city less dependent on cars. She wanted to see more people using bicycles to get around. Over a number of years, the city government set limits on cars and increased the amount of bike paths from 200 kilometers to over 1,000 kilometers.

This year, Parisians are not complaining about too much automobile traffic. Instead, they say there are too many bikes. “Now, it’s really like a bike traffic jam(阻塞),” Thibault Quere, a spokesperson for France’s Federation of Bicycle Users, said. ”It’s kind of a good difficulty to have, especially when we think about what Paris used to be.”

Some famous roads along the River Seine are completely closed to cars. Now you see people riding bikes, running and walking with their families along the river. In another part of Paris, a bike path on Sebastopol Boulevard is one of the busiest in Europe, after opening in 2019. In one week in early September, it reached a record high of 124,000 riders.

The city will host the Summer Olympics in 2024 and plans to add more bike paths by then. Paris wants to reduce its pollution by half during the games, even as visitors from around the world will be in the city for the event. Organizers say all of the competition sites will be reachable by bike through a 60-kilometer network of bike paths.

The change to Paris, however, has not been easy. With more people using bikes, more people are making mistakes. Some of them are new to cycling and disobey traffic rules. But the environment may be improving. Cycling is good exercise and helps reduce pollution, which is still a problem for the large city. The French government blames atmospheric pollution for 48,000 early deaths in the country each year.

Hidalgo was re-elected in 2020 and plans to keep making what she calls a “Paris that breathes”. Her newest five-year bike plan includes over $250 million for more bike paths and bike parking. The new budget is an increase of over $100 million from her first five-year plan.

8 . When wildfire smoke from huge fires in Canada blanketed the US in the summer of 2023, emergency rooms saw an increase in admissions for lung problems, heart attacks and other health issues.

Burning fossil fuels has driven climate change, and now climate change is costing people their health and increasingly their lives, says a new report from the medical journal The Lancet. The eighth annual Lancet Countdown, an international analysis that tracks nearly 50 different health-focused issues affected by climate change, calls for an immediate wind-down of fossil fuel use.

Those with the least historical responsibility for causing climate change are feeling the worst effects. Pakistan—a country responsible for roughly 0.3% of all climate-change-causing carbon emissions, suffered huge floods in 2022 that displaced more than 30 million people and killed at least 1,700. However, wealthier countries cannot be spared. In the US, wildfire smoke this summer sent people to the emergency room from New York to Georgia. In Europe, a 2022 summer heat wave resulted in over 60,000 deaths.

About one fifth of all US residents work outdoors; the percentages are even higher in many other countries. When it gets too hot, it gets harder and harder to work. Last year, the report says, outdoor workers lost more than 140 hours each — or several weeks of pay — because of the intense heat.

The human and economic costs are forecast to grow with every tenth of a degree hotter the planet gets. Heat-related deaths, for example, could increase by nearly five times by the middle of the century, if without immediate reductions to carbon emissions.

“I have a young patient who presents with uncontrollable asthma. She lives right next to a highway and is breathing in harmful air from cars burning gas,” Renee Salas, a doctor at Harvard’s Chan School of Public Health says. “So the treatment she needs is electric vehicles, home weatherization and air purification. These are prescriptions I can’t write.”

9 . Plastic is everywhere in our modern world. Its toughness makes it an extremely useful material from household items to vehicle parts, but that same toughness makes it hard to break down for recycling or disposal (处理). However, Japanese scientists at the University of Tokyo have developed a new plastic material that can be broken down more easily and can self-heal and remember past shapes.

Based on a kind of plastic called an epoxy resin vitrimer, which is brittle (脆性的), the new plastic boasts a huge range of advantages. Once scratched with a knife, it can completely patch itself up after being heated to 150 ℃ for just 60 seconds. When shaped into the shape of a crane, then flattened, it can fold itself back into the crane shape by being heated up. It does all of this much faster than others of its type.

The new plastic can also break down easier. Even if it’s discarded (丢弃) into the environment, it still poses less of a, problem than other kinds of plastic, which the team demonstrated by placing it in seawater for 30 days. It biodegraded by 25% and released molecules (分子) that are essential food for marine life.

The new plastic is more resistant to breaking. It can also repair itself, and can recover its original memorized shape. It even biodegrades safely in a marine environment, according to Shota Ando, a researcher of the study.

The material can be used in a variety of applications, “Infrastructure materials for roads and bridges are often composed of epoxy resins mixed with compounds such as concrete and carbon,” said Ando. “By using the new plastic, these would be easier to maintain as they would be stronger and healable using heat. Unlike conventional epoxy resins, this new material is hard but stretchable, so it could also be expected to strongly bond materials of different hardness and stretch.”

10 . Landscape architect Kotchakorn Voraakhom has designed a new green roof on the Rangsit Campus of Thammasat University, about 25 miles north of central Bangkok, Thailand. Her imaginative work challenges the common thinking that urbanization has a negative impact on the planet, whether flooding, excess (过度的) energy use, disrupted (扰乱) biodiversity or the heat island effect.

The 236, 806-square-foot structure, which opened in December 2019, includes a flood water management system and Asia’s largest rooftop organic farm. It combines modern landscape architecture with traditional agricultural knowledge, creating a green and friendly environment.

The green roof, containing an H-shaped landscape, looks like a futuristic hill with a brick building beneath it. The hill features a complex pattern of zigzagging terraces (之字形梯田) of planted beds, leading all the way down to the bottom. When rainwater hits the roof, it flows down the zigzags while being absorbed by the soil in the beds, The excess water is directed into four storage ponds — with a capacity of up to 3 million gallons. The process slows down the flow speed of rainwater runoff compared to a normal concrete rooftop. This keeps the area from flooding during heavy rains.

The roof’s terraces are filled with organically grown crops, including a drought tolerant variety of rice, many local vegetables and herbs. The farm can supply the canteens on campus with a large amount of rice, herbs and vegetables a year. The food waste is composted (把……制成堆肥) to fertilize the farm, and water from the storage ponds is used to water plants, creating an entirely localized and circular system.

The farm serves as an outdoor classroom and a source of local jobs, too. Farmers offer workshops on sustainable agriculture and nutrition as part of the university’s sustainability curriculum. “Students and community members are invited to participate in seasonal seeding, harvesting, and so on,” says Voraakhom. “The urban farm is training a new generation of organic farmers with real-world skills. It also promotes a sense of community.”