1 . Commercial airlines alone contribute around 3% of total global carbon emissions. But the industry is actively looking for green solutions in the form of sustainable jet fuel, and in one case, that fuel may have had a previous life as your household food waste. In a study released this week in the Proceedings of the National Academy of Sciences, researchers detail a method of transforming food waste into sustainable jet fuel that can be used in existing engines.

Biomass (生物质), such as manure (粪便) and food waste, can be transformed into bio-fuels, which are renewable liquid fuels made from organic matter. Derek Vardon, a senior research engineer at the National Renewable Energy Laboratory (NREL), says that their fuel worked as a mixture of 90% conventional petrol jet fuel and 10% alternative jet fuel required by the industry currently. They also show they could push it to a 70/30 mixture, which will be possible in real world with more time and testing.

Major airline companies are eager to get involved in sustainable aviation fuel because some sustainable solutions, such as battery-operated commercial planes, just aren’t possible yet with current battery technology. A battery-powered plane would be too heavy to fly long distances, so fuel that works in the same way as the fuel we have is a simpler way to trade out emission-heavy fossil fuels.

Vardon says that because the wet waste used in the process would normally go to a landfill (垃圾填埋场) and break down to release greenhouse gases, the process of making and using sustainable aviation fuel could actually have a negative carbon footprint when scaled up.

Commercial airlines are on board to find an affordable and sustainable solution to the carbon-intensive process of air travel. Airlines are looking to hit aggressive sustainability goals by 2050, including decreasing net carbon dioxide emissions by 50%.

3 . An environmental group in Colombia is leading a project to save wild areas in the San Lucas Mountains with the help of coffee growers.

Since 2016, San Lucas areas have been threatened by mining and coca (古柯) planting Gold miners and coca growers make more money than coffee farms. Now the group WebConserva helps link coffee farmers with coffee processors from around the country in order that they can earn more. At the same time coffee farms can serve as boarders around the forests to protect the biodiversity within.

To date, the project includes 10 families who farm 400 hectares of coffee plants. WebConserva said it hopes, in time, 200 families will be included. At that level. 20,000 hectares of untouched forest could be protected. The families promise not to cut down trees to expand their crops or to hunt wild animals. In return, they receive $300 for 125 kilograms of coffee.

Arcadio Barajas is among those taking part. His coffee farm sets up a barrier between cattle farms and forests where wild animals live, thus reducing the possibility of conflict between cattle farmers and wild animals.   “Cutting down the forest to plant coca and killing wildlife were against my faith, and now I feel that growing coffee lets me be a good guard of the land,” he said.

Amnobis Romero is a former coca grower and miner. “Many families depended on illegal activities to support their children years ago. Now, we feel it a duty to look after this biodiversity and leave it for future generations,” he said. Activists want San Lucas to be protected as a national park, but the process has been slow. Carlos Valderrama, director of Webconserva, hopes the project can build production system that will last far into the future. “It protects forests, biodiversity and ecosystems at the same time as improving coffee growers’ quality of life,” he said.

4 . For years scientists have been worried about the effects of air pollution on the earth’s natural conditions. Some believe the air inside many houses may be more dangerous than the air outside.

Most scientists agree that every modern house has some kind of indoor pollution. People began to notice the problem in the early 1970s. When builders began making houses and offices, they did not want to waste energy. To do this they built buildings that limited the flow of air between inside and outside. They also used man — made building materials which are now known to let out harmful gases.

As the problem became more serious, scientists began searching for a way to deal with it. They discovered a natural pollution control system for building green plants.

Scientists believe that a plant’s leaves absorb the pollutants (污染物). In exchange the plant lets out oxygen through its leaves. Studies of different plants show that each absorbs different chemicals. So the most effective way to clean the air is to use different kinds of plants.

5 . It’s no secret that inhaling (吸入) smoke is bad for your lungs. But now, scientists are suggesting smoke may also carry and spread infectious diseases. The theory, published in Science Magazine, is based on research that found wildfire smoke is crowded with thousands of species of microorganisms. Some of these microorganisms, including bacteria and fungal spores, are known to cause disease.

The new research suggests that when a wildfire burns plant or animal matter and disturbs soils, it exposes thousands of species of bacteria and fungi that otherwise might not easily become airborne (空气传播的). You might think the high heat from fire would kill these organisms, but one study mentioned in the article found that some bacteria even multiply post-fire. Scientists say the organisms attach to smoke particles, allowing them to travel thousands of miles across continents.

Dr. Peter Chen, director of the Division of Pulmonary and Critical Care Medicine at Cedars-Sinai Medical Center in Los Angeles, is interested in the theory but somewhat skeptical that the microorganisms in smoke would actually cause infections. Many bacteria and fungi don’t cause lung infections, says Chen, but it’s certainly possible that a significant amount could worsen symptoms in someone with a preexisting lung condition. “I always thought it was the particles in smoke that were causing these issues,” says Chen. “But when I read this, I started thinking: Could it be the microorganisms that are also worsening existing illnesses?”

Whether the microorganisms in smoke actually cause infection or simply worsen potential respiratory (呼吸的) issues, the article raises a new health threat that is “certainly alarming”, says Kelsey Jack, an associate professor of environmental and development economics. This is especially true for lower-income populations, Jack says, because people with fewer means are often more exposed to the environment. If smoke is affecting the air quality in a certain area, the people who work outside, or who have to go to the office on foot or by bike will inhale more smoke than those who drive.

But until more research is done, Chen says the best thing people can do is just follow existing recommendations when air quality is poor—including staying indoors, keeping windows and doors closed, using HEPA filters and running air conditioning.

6 . Soot (煤) pollution is speeding up climate-driven melting in Antarctica, a new study suggests, raising questions about how to protect the delicate continent from the increasing number of humans who want to visit.

“It really makes us question, is our presence really needed?” says Alia Khan, one of the authors of the new study. “We have quite a large black carbon footprint in Antarctica, which is enhancing snow and ice melt.”

Black carbon is the leftover thing from burning plants or fossil fuels. Soot in Antarctica comes primarily from waste gases of cruise ships (游轮), vehicles and airplanes, although some pollution travels on the wind from other parts of the globe. The dark particles (微粒) coat white snow and absorb heat from the sun the way a black T-shirt does on a warm day. The blanket of dark bits speeds up melting that was already happening more quickly because of global warming.

When snow and ice are uncovered, they reflect an enormous amount of sunlight before it can turn into heat. “These are the mirrors on our planet,” says Sonia Nagorski, a scientist at the University of Alaska Southeast. “When those mirrors are covered in a film of dark bits, they don’t send back that much light and heat. That means more heat is trapped on Earth, speeding up melting and contributing to global warming.”

As a scientist who personally visits Antarctica every year, Khan says she is troubled by her own research results. On the one hand, she goes to Antarctica to collect crucial data about how quickly the snow and ice there are disappearing. “But then when we come to conclusions like this it really does make us think twice about how frequently we need to visit the continent,” she says, “and what kind of regulations should be placed on tourism as well.” That could mean requiring that cruise ships and vehicles be electric, for example, or limiting the number of visitors each year.

8 . A team led by researchers from the UK examined waterbird data from 1506 protected areas and analyzed more than 27, 000 bird populations across the world. They compared waterbird populations before and after the establishment of protected areas and also compared trends of similar populations within and outside of protected areas.

“Our study shows that, while many protected areas are working well, many others are failing to have a positive effect, ” lead author Hannah Wauchope says in a statement. “In the majority of places we looked, bird populations were stable or were increasing, but some of them weren’t doing any better than in unprotected areas, “ she adds. “That’s disappointing, but not surprising. There seems to be the disconnection between people talking about how much land is protected and whether those areas are actually doing anything positive. ”

This study comes ahead of a United Nations meeting in China to discuss biodiversity goals for the next decade. Several countries have already committed to protecting 30 percent of the planet by 2030, yet the researchers say this alone does not necessarily guarantee positive out- comes for species.

“An obsession(迷恋)with reaching a certain area-based target-such as 30 percent by 2030-without focus on managing existing protected areas appropriately will achieve little, ” co-author Julia Jones says. “When world leaders gather in China later this year to set targets for the next decade, I really hope to see a change of their focus, rather than simply saying how much surface area they are going to protect. ”

According to Thomas Brooks, chief scientist at the International Union for Conservation of Nature, who was not involved in the study, waterbirds are a good example of a group facing the consequences of human behaviors that cause biodiversity loss. These animals respond quickly to changes in site quality and are broadly distributed, clearly reflecting the impact of protected areas.