1 . 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.

2 . Every year, as the surface water temperature off the United States mid-Atlantic coast rises steadily from late spring through the summer, a pocket of uncharacteristically cool and crisp water gets trapped at the bottom of the ocean. Packed with nutrients this thick band of cold water, known as the mid-Atlantic cold pool, is a vital home for shellfish species. Extending at its seasonal peak from Nantucket, Massachusetts, to Cape Hatteras, North Carolina, the cold poll creates a diverse ecosystem ranging from algae(海藻)to fish — and some of the most valuable shellfish fisheries in the United States.

Now, however, two pressures have scientists worrying about whether the cold pool will last. The first is no surprise: climate change. Over the past five decades, climates change has destabilized the cold pool, causing it to warm and shrink. Compared with 1968, the cold pool is now 13℃ warmer and has lost more than one-third of its area.

The second concern is 1ess certain. In 2023, the US federal government approved plans to install(安装)98 wind turbines(涡轮机)off the New Jersey coast, covering an area of more than 300 square kilometers. Yet putting so many turbines to the seafloor could have unexpected consequences for the cold pool. That’s why Travis Miles, a researcher at New Jersey’s Rutgers University, and his colleagues are investigating. So far, Miles and his colleagues can’t definitively say what will happen to the cold pool, saying more research is needed to assess how climate change and offshore wind, together, could affect the cold pool. However, their initial analyses suggest the cold pool should be fine — at least in normal conditions.

New Jersey’s offshore wind plans are strongly opposed mainly by fossil fuel-industry funded efforts. Miles worries that an overabundance of caution or fear of potential impacts, including on the cold pool, might slow down the development of renewable energy. “...it’s quite clear that climate change is far more damaging than installing wind farms,” he says. “I don’t think any scientist would argue with that.”

3 . Like many of the Indigenous (土著的) communities across the Australian continent, the remote communities in north-west New South Wales are struggling. Many of the 300 or so residents rely on welfare. Higher electricity bills—up to $3,000 a quarter for some households—further worsen the poverty. They’re always at the end of the power line, so the service that is there is quite extraordinary in terms of cost. It’s a real problem that needs to be fixed.

To that end, Anderson and other Indigenous leaders have formed the First Nations Renewable Energy Alliance (FREA) to push for renewable energy in Indigenous communities. They partner with private enterprise to support Indigenous communities looking to switch to renewable energy.

“We can build a power station where the community exists,” Anderson says, “so people are able to successfully live in the environment the way they want to live and have access to power which enables them to better determine their economic future.”

Only a handful of Indigenous communities have set up renewable energy projects in Australia. The Indigenous-owned and -operated company AllGrid Energy, for instance, has installed solar panels and battery storage systems to replace diesel (柴油) generators in the communities of Ngurrara and Kurnturlpara in the Northern Territory’s Barkly Tableland. Within two months of the system being installed in May 2016, people were moving back to their homelands, the communities growing from just two permanent residents to about 40.

But FREA will go one step further, working with community leaders and acting as a conduit (纽带) between the communities and the businesses they are dealing with. This is essential, says Anderson, to avoid predatory (吞并) practices they have seen in the past, with companies “playing on the psychology of poverty” to gain advantage. The FREA has drafted terms of agreements that will guide how companies engage with Indigenous communities for renewable energy projects.

One of the next steps for FREA will be to identify a community that can act as a test case for a renewables project. “Our experience is that if we can make it work for one community, it will work in every other community,” Anderson says.

4 . In 2014, Xu Yitang, a student at the National Academy of Chinese Theatre Arts, saw corals at an aquarium for the first time.

Little did he know the chance ______ with the creature would spark a lifelong ______. He began to ______ the local market to learn about coral farming from merchants selling plants, fish and corals. He also searched for information on relevant forums online, and before long, started ______ a coral in a small fish tank at home.

“The coral organism is quite ______ and has extremely high ______ for water quality,” recalls Xu. “In the beginning, its state was not good.”

As he became better ______ of the creature, he learned that coral reefs are known as “tropical rainforests” and “underwater gardens” of the ocean, providing ______ for a quarter of all marine life. ______, rising sea temperatures have led to coral ______. Xu felt an increasing sense of urgency and ______ to protect them.

Fast-forward to today, he ______ a coral conservationist in a Sanya-based tropical biological research center.

Each day, he spends several hours diving deep under the waves to observe and ______ the growth and development of the creatures.

His story has been ______ in the recently premiered online program Burning Youth that aims to use documentary shorts and in-depth studio interviews to ______ the inspiring stories of young Chinese people from various walks of life.

5 . Whenever I order food for delivery, I play a little game to guess how many sets of tableware(餐具)the restaurant will provide with my meal. Sometimes restaurants will throw in two, three or four sets for just one order. But I rarely need any tableware at all, and the waste goes into the trash or collects dust in a kitchen drawer.

Researchers working with Chinese technology group Alibaba tried a simple approach to this problem. Instead of just wastefully doling out tableware, the company required food-delivery customers in some cities in China to pick how many sets of tableware they wanted to receive.The default (默认设置)was set at zero. The result, published today in the journal Science, was a 638% increase in the share of no-tableware orders. If applied across China, researchers found, the approach would save nearly 22 billion sets of plastic tableware. The study doesn’t cover carbon emissions, but it’s safe to say that the impact would be significant. It struck me as a useful reminder of the many low-hanging fruits across the economy that can cut waste, and emissions.

Nudging its customers cost Alibaba nothing more than a few hours of software engineering time and the impact it brought was immense. The concept of nudging comes from the field of behavioral economics known as nudge theory. It suggests that a slight action can encourage good human behavior without the need for policies that limit choice or economic punishment that raises the cost of bad behavior. To nudge customers to eat better, for example, a restaurant might organize its menu by listing healthy options first and bury unhealthy ones at the bottom. More recently, some big companies like Google have also begun to use nudges to advance climate objectives.

Behavioral economics broadly, and nudges more specifically, aren’t without controversy. Some might think it assigns consumers responsibility for addressing environmental challenges. But there is another way to look at it. In the absence of necessary policy—and policy is needed一companies can help encourage a widespread shift of consumer behavior.

And all of that behavioral change can add up. The International Energy Agency found in 2021 that small behavioral changes in energy consumption such as walking instead of driving and adjusting the thermostat could in total shave off 4% of global emissions. The more that companies can do to facilitate such changes, the better.

7 . Shop Sustainably

If you have to name one thing that contributes most to your ecological footprints, you may say the energy you use at home, or your car’s emissions.     1     Knowing this can make your grocery shops more planet-friendly. Here is what you can do to help shop sustainably.

●    2     Using those is a great first step. If you get some, do remember to fill them with your purchases. When you adapt yourself to reusing them, then you’ll cut your consumption of single-use plastic bags even further.

●Avoid unnecessary packing. Buy loose fruit and vegetables instead of pre-packaged produce, and avoid products that contain multiple single packages or double packaging, like grain in a box and a bag. Consider switching from tea bags and coffee pods to tea leaves and ground coffee.     3    

●Go organic when you can. In addition to the benefit organic farming has to insect biodiversity, it’s also considered more sustainable and better for the environment.     4    Choosing free-range or Marine Stewardship Council-certified products also encourages environment- and animal-friendly food production.

●Buy seasonal and native products.     5     So you can avoid buying goods that have travelled long distances to reach your plate. As well as opting for local goods, depending on where you live, in the supermarket, you can also buy directly from the source at farmers’ markets.

8 . In the rich countries of the West, the electric vehicle revolution is well underway. Climate-conscious consumers drive Teslas or Polestars for reasons of morality and fashion. Poorer countries are also experiencing a wave of electrified trend. In Bangladesh, electric three-wheeler taxis, known as tuk-tuks, are rapidly replacing gas-powered ones on the streets. Such electric vehicles are climate friendly, cost effective, and help reduce air pollution.

Yet a glance under the hood (引擎盖) of these vehicles reveals a poisonous secret: each tuk-tuk runs on five massive lead-acid batteries, containing almost 300 pounds of lead in total. Every year and a half or so, when those batteries need to be replaced and recycled, about 60 pounds of lead leak into the environment. Battery recycling, often at small-scale unregulated factories, is a highly profitable but deadly business.

Lead is dangerous, and any exposure to it is harmful to human health. Lead that has entered the environment hurts people on an extraordinary scale. The numerous ways lead enters air, water, soil, and homes across the developing world — and the enormous damage it does to human health, wealth, and welfare — causes one of the biggest environmental crises in the world yet receives little attention.

The World Bank estimates that lead kills 5. 5 million people per year, which would make it a bigger global killer than AIDS, malaria, diabetes, and road traffic deaths combined. On top of the shocking deaths, the social burden of lead poisoning is extraordinary, as is its contribution to global inequality — our research on the cognitive effects of lead poisoning suggests that it may explain about one-fifth of the educational achievement gap between rich and poor countries.

But unlike many challenges faced by developing countries, lead poisoning is a problem that is fixable with some attention and a relatively modest financial investment. Better monitoring, research, and rules can help protect children all over the world from the dreadful effects of lead poisoning and reduce the massive global costs it brings.

9 . Before the year has even come to a close, climate experts are certain that 2023 will be the hottest year in recorded history.

On Dec. 6, the Copernicus Climate Change Service (C3S) — part of the European Union's space program — revealed that this year's average global temperatures have been 2.6℉ (1.46°C ) higher than temperatures in preindustrial times and 0.2°F (0.13°C) higher than January to November in 2016. These “extraordinary” temperatures mean that 2023will be “the warmest year in recorded history,” C3S deputy director Samantha Burgess said in a statement.

The researchers note that this year's record heat was partly caused by the latest El Nino event — a phenomenon where warmer water near the equator triggers warmer global air temperatures — that began in June. Some other experts have suggested that the January2022 eruption of Tonga's underwater volcano, which pumped record levels of water vapor into the atmosphere, may also be partly responsible.

Despite these factors, the major cause of climbing temperatures is global warming caused by runaway greenhouse gas emissions, which, noted in a C3S statement, have trapped more than 25 billion atomic bombs' worth of energy in our atmosphere over the last 50 years. And still worse, the global carbon emissions have reached a new high this year, according to scientists at the United Nations Climate Change Conference of the Parties (COP28) On Dec 4.

The effects of global warming are becoming more obvious. In 2023, research revealed that climate change is causing major US cities to sink and more than half of the world's largest lakes and reservoirs to shrink. Studies also predicted that the Gulf Stream, which plays a vital role in ocean circulation, could collapse by as early as 2025, and that rising sea levels could swamp the U S coastline by 2050.

However, scientists say that we still have time to prevent further disaster. Leading climate change expert Michael Mann, from the University of Pennsylvania, recently wrote that “we can still stop the worst effects of climate change” if we stop emitting greenhouse gases as soon as possible.

10 . Leave-No-Trace Camping

For those of us who love spending time in the great outdoors, wild spaces are very special. These are places we visit to recharge, or to fill our hearts with natural beauty.    1    If you feel this way, then you’re the perfect person to promote and practice Leave-No-Trace camping.

Its principles are to treat the wilderness the way a decent visitor would and leave everything just as you found it, with no evidence that you passed through.    2    That’s because your visit makes a minimal impact on the environment.

You can carry out these ideals in a number of ways. Begin by packing out all your litter. Whenever you go camping, take an empty trash bag with you and put all garbage into the bag. In addition, try not to damage vegetation.    3    Wherever you go, think about what your heavy shoes or boots are doing to the plants underneath and try to keep damage to a minimum.

It’s also important that you should not take things away from the wilderness. Rocks, plants, flowers and seashells are all part of the natural landscape.    4    Plus, many animals find homes and food in abandoned shells and flower-heads, and these are things they would miss if you collected them.

Leave-No-Trace camping is about being respectful and thoughtful. It’s about honoring the natural world and the creatures that live in it. If you love seeing an untouched mountain stream or a lovely field of wildflowers, then you’ve already taken the first step.    5