1 . Deserts could be the best places on Earth for harvesting solar power. They are spacious, relatively flat, and never short of sunlight. So researchers imagine it might be possible to transform the world’s largest desert, the Sahara, into a large solar farm, capable of meeting four times the world’s current energy demand.

While the black surfaces of solar panels absorb most of the sunlight that reaches them, only around 15% of that incoming energy gets turned into electricity. The rest is returned to the environment as heat, affecting the climate. If these effects were only local, they might not matter in a thinly populated desert. But the area of the installations in the Sahara would be vast, covering thousands of square miles. Heat released from an area this size will be redistributed by the flow of air in the atmosphere, having regional and even global effects on the climate.

A 2018 study used a climate model to assess the effects of building massive solar farms in the Sahara. The model revealed that when the size of the solar farm reaches 20% of the total area of the Sahara, the heat released by the darker solar panels creates a big temperature difference between the land and the surrounding oceans that ultimately lowers surface air pressure and causes wet air to rise and condense (凝结) into raindrops. With more rainfall, plants grow and the desert reflects less of the sun’s energy since vegetation absorbs light better than sand and soil. With more plants present, more water is evaporated (蒸发), creating a better environment that causes vegetation to spread.

So, a large solar farm could generate enough energy and at the same time turn one of the most abominable environments on Earth into a habitable place. Sounds perfect, right? Not quite. In a recent study, we used an advanced Earth system model to closely examine how Saharan solar farms interact with the climate. It showed there could be unintended effects in remote parts of the land and ocean.

We are only beginning to understand the potential consequences of establishing massive solar farms in deserts. Solutions like this may help society reduce the use of fossil energy, but Earth system studies like ours underscore the importance of considering the numerous coupled responses of the atmosphere, oceans, and land surface when examining their benefits and risks.

2 . Imagine a world where nothing ends up in landfill. Instead, everything can be reused and recycled, creating products that never reach their “end of life”. According to a recent report by the Circle Economy Foundation, only 7.2% of all used materials are being cycled back to be reused and recycled without creating waste.

An Italian company aims to change this by creating furniture products made from a plastic-like biomaterial, which is fully organic and biodegradable (可生物降解的), and can be used over and over again. Using fruit peel, orange seeds and coffee grounds collected from businesses in Italy, the company can redistribute products to the same businesses for use in their offices, instead of furniture made from common plastic. If, by mistake, any of the material ends up in the ocean, it doesn’t produce any microplastics.

Each product is made through a four-step process. First, the food waste is dried and crushed into a very fine powder. Then, the powder is mixed with a biodegradable plastic alternative known as polyhydroxybutyrat (PHB), with the fruit waste making the PHB more study (坚固的). The material is then turned into a filament (细丝) and, using a spool, put into a 3D printer.

Because a lot of food waste would be buried and incinerated in the landfill, which would produce lots of carbon dioxide, Reusing fruit peel and coffee grounds decrease carbon dioxide from the production of plastic, according to the director of operations in the company. He adds that the biomaterial is as sturdy as wood, and won’t begin to break down unless it’s touched by water, bacteria or acidity.

Despite its eco-friendly benefits, the biomaterial is expensive. It costs probably six times more than common plastic, and it is a very difficult and expensive process, so this is why many companies aren’t doing it.

However, the director is hopeful that in a few years, as-more consumers and businesses are forced to face the damage that unsustainable plastic is doing to the planet, the biomaterial will be much more widely used. “We really believe this is the material of the future,” says the director. “Little by little, a step at a time.”

6 . The Thermo Fisher Scientific Junior Innovators Challenge is a science competition for U. S. middle-school students. It's run by Society for Science, which also publishes Science News Explores. The 30 finalists in this year's competition traveled to Washington, D. C. and also showed off their research projects.

Sharanya Chudgar, 14 years old, is one of the finalists in the competition and built a trash-collecting robot. The wheeled machine of the robot uses sensors to spot litter and a pan to pick it up. The robot's metal-detecting sensor helps it sort garbage from recyclables. And a light sensor can let the robot's solar panel angle itself toward the sun, collecting as much energy as possible.

Sharanya got the idea to build her trash collector by participating in litter cleanups. "When I signed up to volunteer at our local trash cleanup, I saw how much litter poliution there was and I knew that I had to fix this problem," Sharanya says. "People do have very limited time and resources, right? But robots don't. So it was then that my project idea formed in my head."

"Building the robot is my favorite part of this project," Sharanya says. "Ever since first grade, I've loved building Legos and building my robot felt just like building a Lego. But this project was a completely new experience since I hadn't ever had any experience in robotics before. Throughout the project, I had to use tons of power tools and I even had to cut pieces of metal to certain lengths. Whenever I needed to use a power tool, I had to turn to my dad who was always there to help out if necessary."

"It might seem difficult at times, but sticking to this and changing just one variable at a time gets you the best results," Sharanya says. This middle school scientist is solving global problems of litter pollution. For some, a science project might be an assignment or a fun hobby. But for Sharanya, doing research can also be a chance to help others and make the world a better place.

8 . 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.

9 . 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.

10 . 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.”