Now, Earth Day is celebrated every year on April 22. A man, called Senator Gaylord Nelson Take, was determined to change the way we treated our planet. He didn’t stop his work until he had made a difference.

In 1963, Senator Gaylord Nelson wasn’t happy with the earth’s condition. He wanted to clean up the planet and solve pollution and environmental problems. As a senator, Gaylord Nelson was someone chosen by US citizens to help make laws, so he had a lot of power. He went to John F. Kennedy, the President at the time, with his concerns. The President agreed that the planet’s environment was a serious issue, so President Kennedy went around the country on a five­day tour to promote (宣传) the idea of cleaning up the planet. People began making small changes, but it wasn’t enough.

A few years later, Senator Nelson decided to put one day aside every year for the cause of saving the planet. On April 22,1970, the first Earth Day was celebrated; 20 million American demonstrators (示威者) took part in Earth Day activities. Since then, Earth Day has become an international holiday. People all over the world are doing something to make the earth a cleaner, better place. Today more than 500 million people in 164 countries participate (参与) in Earth Day festivities!

Then, what can you do to make a difference?

*Encourage your family to recycle on a regular basis. It is a good way to help the earth!

*Switch to energy­efficient light bulbs in your house to reduce the effects of global warming.

*Every glass bottle you recycle saves enough energy to run a TV for an hour and a half, while recycling an aluminum (铝) bottle can save enough energy to run your TV for three hours!

*Turn out the lights when you leave a room — unless someone’s still there!

*Use re­useable containers for your school lunches and snacks.

They give us paper and fuel, as well as vital ecological services-like cleaning the air, storing carbon and providing habitat. We’re talking about trees, of course. But human changes to the environment largely appear to be causing profound transformations in trees around the world.

In a new study, scientists reviewed global research on trends in tree seedlings (籽苗), growth and death. They combined those data with an analysis of deforestation. And they found that worldwide, older trees are dying at a higher rate than in the past due to factors like rising air temperature, wildfires, drought and pathogens (病原菌).

“And most of the drivers of that decrease in large, old trees are increasing themselves, such as temperature is going up, droughts are more severe, wildfires, windstorms and deforestation are all on the increase—although variable across the globe — they’re generally increasing. And so for both the loss has already occurred, but we expect more continued loss of big, old trees,” said Nate McDowell, an earth scientist at Pacific Northwest National Lab, who was one of the study’s authors.

“So if we have an increasing rate of death, particularly of the larger, older trees, what’s left are the younger trees. So that’s why, on average, through the loss of bigger, older trees, our forests are becoming naturally younger and shorter.”

This is a problem, because old trees are vitally (至关重要) important.

“For sure, the increase in death does limit the carbon storage (储存) of an ecosystem and can force the system to become a carbon source to the atmosphere. The second reason we care is from a biodiversity (生物多样性) perspective (角度): Old trees tend to house a higher biodiversity than young forests do. And another reason is beauty: As a society, we care about these trees. We have national parks named after these big trees. So there’s a personal reason for people to care about this as well.”

Imagine an area 34 times the size of Manhattan. Now imagine it covered ankle-deep in plastic waste—a total of about 19 billion pounds of garbage. 【小题1】.

“We’re being overwhelmed(淹没) by our waste,”said Jenna Jambeck, an environmental engineer who led the 2015 study that determined this astonishing number. 【小题2】, unless something is done to stop the tide of garbage.

Plastic—a widely-used material—has in many ways been a benefit to humans but it has also caused a growing problem. Today, plastics are the No.1 type of garbage found in the sea. Ocean Conservancy, a nonprofit that organizes an annual coastal cleanup event worldwide, said plastic waste makes up around 85 percent of the garbage collected from beaches and oceans.

Ocean Conservancy says plastics are believed to threaten(威胁)at least 600 different wildlife species(物种). 【小题3】; a growing body of evidence suggests humans are consuming plastics through the seafood we eat. A research suggests some plastics could be poisonous to humans, and could potentially increase the risk of health problems.

【小题4】. At the Economist World Ocean Summit this week, ten nations announced to reduce plastic sea liter as part of UN Environment's CleanSeas campaign. 【小题5】Corporations also have a role, as do individuals. We can start by thinking twice before using single-use plastic products—and when we do use them, we should take care to properly throw them off or recycle.