Sometimes called Amazonia, the rainforest of the Amazon River basin is the largest in the world. It stretches (延伸) across more than half of Brazil and parts of seven other South American countries (and French Guiana). With a land area of 2.7 million square miles, the Amazon rainforest is almost two thirds the size of the US.

Rainforests are important to the health of the entire planet. Often called "the lungs of the planet", the Amazon rainforest, with its rich plant life, stores carbon dioxide while giving out the oxygen we need to survive.

Fortunately, over the years, Brazil has also become a world leader in rainforest preservation. A law called the Forest Code, originally passed in 1965, requires the Amazon’s farmers to protect 80 percent of their land from farming. And democratic governments beginning in the early 1990s began to enforce it seriously.

Efforts to save the Amazon increased under President Luiz Inacio Lula da Silva (2002—2011). Brazil set aside about 150 million acres of the rainforest, an area about the size of France, for protection. Deforestation fell by 74 percent between 2004 and 2009.

Other countries of the Amazon have also done their parts. This year, Peru created a forest reserve about the size of California’s Yosemite National Park.

Blue Planet II's latest episode (情节) focuses on how plastic is having a destructive effect on the ocean and slowly poisoning our sea creatures. Researchers recently also found that sea creatures living in the deepest place on Earth, the Mariana Trench, have plastic in their stomachs. Indeed, oceans are drowning in plastic.

Though it seems that the world couldn't possibly function without plastics, plastics are a remarkably recent invention. The first plastic bags were introduced in the 1950s, the same decade that plastic packaging began gaining popularity in the United States. This growth has happened so fast that science is still catching up with the change. Plastics pollution research, for instance, is still a very early science.

We put all these plastics into the environment, but we still don't really know what the outcomes are going to be. What we do know, though, is disturbing. Ocean plastic is estimated to kill millions of marine animals every year. Nearly 700 species, including endangered ones, are known to have been affected by it. One in three leatherback turtles, which often mistake plastic bags for jellyfish, have been found with plastic in their bellies. Ninety percent of seabirds are now eating plastics on a regular basis. By 2050, that figure is expected to rise to 100 percent.

And it's not just wildlife that is threatened by the plastics in our seas. Humans are consuming plastics through the seafood we eat. I could understand why some people see ocean plastic as a disaster, worth mentioning in the same breath as climate change. But ocean plastic is not as complicated as climate change. There are no ocean trash deniers (否认者), at least so far. To do something about it, we don't have to remake our planet energy system.

This is not a problem where we don' t know what the solution is. We know how to pick up garbage. Anyone can do it. We know how to deal with it. We know how to recycle. We can all start by thinking twice before we use single-use plastic products. Things that may seem ordinary, like using a reusable bottle or a reusable bag-when taken collectively, these choices really do make a difference.

A Day in the Clouds

The air is thin and we have to rest several times on the short hike from camp. To our left, snow-covered mountains disappear into clouds that seem almost close enough to touch. On the plain in front of us, we can just make out a herd of graceful animals. This is why we’re here—to observe Tibetan antelopes.

Tibetan antelopes live on the plains of Tibet, Xinjiang, and Qinghai. Watching them move slowly across the green grass, I’m struck by their beauty. I’m also reminded of the danger they are in. They are being hunted, illegally, for their valuable fur.

My guide is Zhaxi, a villager from Changtang. He works at the Changtang National Nature Reserve. The reserve is a shelter for the animals and plants of northwestern Tibet. To Zhaxi, the land is sacred and protecting the wildlife is a way of life. “We’ re not trying to save the animals,” he says. “Actually, we’ re trying to save ourselves.”

The 1980s and 1990s were bad times for the Tibetan antelope. The population dropped by more than 50 percent. Hunters were shooting antelopes to make profits. Their habitats were becoming smaller as new roads and railways were built.

In order to save this species from extinction, the Chinese government placed it under national protection. Zhaxi and other volunteers watched over the antelopes day and night to keep them safe from attacks. Bridges and gates were added to let the antelopes move easily and keep them safe from cars and trains.

The measures were effective. The antelope population has recovered and in June 2015, the Tibetan antelope was removed from the endangered species list. The government, however, does not intend to stop the protection programmes, since the threats to the Tibetan antelope have not yet disappeared.

In the evening, I drink a cup of tea and watch the stars. I think about the antelopes and what Zhaxi told me. Much is being done to protect wildlife, but if we really want to save the planet, we must change our way of life. Only when we learn to exist in harmony with nature can we stop being a threat to wildlife and to our planet.