1 . Cows produce much methane (甲烷) the world’s second worst greenhouse gas, as they break down the grass. They are a large source of the greenhouse gases that are driving climate change. Now scientists have shown the pollution from cows can be reduced by adding a little seaweed (海藻) to their food.

Recently, the researchers from the University of California studied 21 cows on a farm for about five months. They taught the cows to get their food from inside a special hood, which allowed the scientists to know the amount of the methane the cows were giving off. They added a small amount of seaweed to the cows’ food.

The consequences were surprisingly good. In some cases, the cows produced 82% less methane. The improvement depended on the kind of food the cows were given. Even the worst-polluting cows produced 33% less methane. Over the five months, the scientists didn’t see any signs that the cows’ stomachs were getting used to the seaweed and starting to produce more methane again. What’s more, the cows that were fed seaweed gained just as much weight as the other cows.

But there are still some big problems with the idea of feeding cows seaweed. For one thing, there’s not enough seaweed to feed all of the cows in the world. So farmers would have to figure out a way to grow lots of seaweed. A bigger problem is that for most of their lives, cows live in the fields, where they eat grass. That means there’s no chance to feed them seaweed every day.

Still, as the study shows, something as simple as feeding cows seaweed can help reduce some of the pollution causing the climate crisis.

4 . Where there are people, there are chickens. One result of a huge chicken population is a huge amount of chicken feather, which are normally burned or treated as rubbish, polluting the environment.

Ryan Robinson, a biology graduate from Imperial College London, believed there would be a different solution for this feathery waste. Therefore, along with designer Elena Dieckman, he has discovered a way to turn feathers into an insulating (绝缘的) material for buildings or a packing material for food or medicine. The pair has formed a start-up, called Aeropowder, to try and turn their invention into a commercial product. They believe the new material could have a range of uses.

“Currently feathers are mainly transformed in this country to a low-grade animal food called feather meal. Feathers can also be burned or thrown away. And these methods do not make use of their amazing natural properties (特性).” says Robinson.

It turns out that feathers are quite a wonder material. “Feathers are insulating due to their structure, which are hollow fibers,” says Robinson. Extra air in the fibers means less heat transfer. “What has been surprising is how well the material has performed, and we hope to continue to make it better and better. “The current form of Aeropowder’s material looks much more like a fattened brick of feathers. It’s flexible and light.

Aeropowder isn’t the first to try to find a further use for this very common waste product. In 2011, researchers from the University of Nebraska-Lincoln in the US suggested that chicken feathers should be used to help produce a kind of environmental plastic. The next challenge will be to find a way for this material to be made close to where the chickens are, rather than sending it far away to a processing plant.

“There is still work to be done to get our material tested with early adopters,” Robinson says. “But in the long term, we wish to become the world experts in feather-based materials.”