2 . Nobody wants to snack on plastic bags or soda rings, but according to a recent study from the University of Neweastle, we could be consuming roughly a credit card's worth of plastic every week.

Microplastic, which are less than a quarter-inch size and come in various shapes, have polluted the natural world and infiltrated(渗入)our bodies. The first clue to microplastic exposure in humans came around 2013, when scientists discovered plastic particles in seafood prepared for consumption. But in 2019, when the University of Newcastle study was published, the scientific community understood that the problem was considerably broader. Microplastics shed off clothes and tires and have been found in beer, honey, table salt and other food items. We breathe in plastic staying in the air and drink plastic floating in our drinks. It's no stretch to conclude that our exposure is significant. What we don't know is what this means for us.

The amount of evidence collected on this subject is growing rapidly, according to Scott Coffin, a toxicologist(毒理学家). Studies done on mice and rats have found that plastic in their bodies can severely damage cells and cause stress.

Because microplastics are too small to clean up, the only solution is to stop plastic waste at the source. And doing so would take a thorough adjustment, given that plastics are deeply embedded in our economy and lifestyle. Stopping using them would fundamentally affect countless industries, including textiles(纺织业), transportation and manufacturing.

"I think we need to have more studies coming out that are directly related to human health before we see a lot more concern from the general public," Scott said. "It takes a lot to convince people that something that is really convenient for them to use is something they should sacrifice."

The question of microplastics and human health needs more attention—from the scientific community ,the general public, the government and funding groups. The issue isn't being ignored, but it's not being prioritized either.

3 . Ladies and gentlemen，I returned to this year in a time machine.In the year 2500，we are able to travel through time to any year in the history of the earth.This year is your last chance to change your lifestyle to save the earth.

Beginning in the middle of the 20th century，a few people were worried about polluting the earth’s water and air，but most people did not change their way of life.Instead，they continued to pour dangerous chemicals and other waste into lakes and seas，to drive more and more cars and trucks，and to cut down trees.

By the year 2200，the earth’s water was completely polluted.People could no longer drink water，and they had to use other types of liquids.

So，by the year 2300，there were so many people that food became scarce.There was no water to grow food and all of the fish in the lakes and seas died because of pollution.Terrible wars broke out between the rich and the poor.Scientists were working very hard to find another planet in space where humans could live.

By the year 2400，the air was too polluted for humans to breathe.So we had to leave the earth.But only the rich were able to leave.Where did we go？Nowhere.The scientists did not find another safe planet，so now we must travel around the universe in our spaceships.We are still looking for a place to call our home.

So，it is up to you to change the history.There is still hope.You must change your lifestyle now，before it is too late.

4 . The World Health Organization says that 92 percent of the world’s population lives in areas of high air pollution. Experts say much of that pollution comes from vehicles fueled by diesel. Many cities in Europe have called for ending the production of diesel cars. They hope to replace them with electric vehicles as battery life for those vehicles improves.

London is one of the most heavily polluted cities in Europe. Levels of harmful gases in the city are regularly higher than limits set by the European Union.

Martin Williams, with King’s College London, says pedestrians often do not realize how close they are to air pollution sources because they cannot see them. “One of the difficulties of getting the message across to the public at large these days is that air pollution, although it’s a major public health problem, is actually invisible. Not like the smogs of the 1950s and 60s when not only could you see it, you could barely see anything else.”

Williams adds that toxic gases from diesel cars have led to public health concerns. He says people across Great Britain have died too early because of the pollution. “The main problem that you are breathing in are the particulates, the soot largely from diesel exhausts, which is the primary problem as far as public health is concerned. The other pollutant that’s more recently become an issue is nitrogen dioxide, again largely from diesel.”

Areeba Hamid is with the environmental group Greenpeace. She says, “It’s quite clear that the car industry is feeling the pressure of a public health crisis owing to air pollution in big cities in particular and the aftermath of the diesel-gate’ scandal, which is the reason why it’s looking to produce new electric models.”

Experts say electric cars could offer the answer to air pollution in major cities. They add, however, that the electricity should be created using renewable energy.

6 . The amount of plastic pollution in the oceans is rapidly increasing. This is problematic, as at least 700 species of sea animals may mistake it for a tasty snack. While we know that some species seem to eat plastic because it looks like jellyfish or some other food source, less research has been carried out into what plastic smells like to marine animals.

But now, a study from the University of North Carolina has found that the coating of algae that naturally builds up on ocean plastics causes the rubbish to give off the scent of food.

The researchers took 15 loggerhead turtles, each around five months old, and placed them in a laboratory tank. They then piped in clean water, clean plastic, turtle food, and plastic that had been immersed in the marine environment for five weeks.

The turtles showed no reaction to the smell of clean water or clean plastic. But when they were exposed to the smell of ocean-soaked plastic 'or turtle food, they exhibited food-seeking behaviors like reaching their noses out of the water or showing increasing activities.

“This finding is the first demonstration that the smell of ocean plastics causes animals to eat them,” said Dr. Kenneth J Lohmann, who took part in the study. "It's common to find loggerhead turtles with their digestive systems fully or partially blocked because they've eaten plastic materials. There are also increasing reports of sea turtles that have become ill and stranded on the beach due to their ingestion of plastic."

According to the researchers, areas of the ocean with dense concentrations of plastic may trick turtles and other animals into thinking that there is an abundant food source. "Once these plastics are in the ocean, we don't have a good way to remove them or prevent them from smelling like food," said Lohmann.

7 . Carbon dioxide makes up less than one percent of the Earth’s atmosphere. But the gas is very important to life on Earth. Scientists are finding that processes involving carbon dioxide affect our climate in ways that are difficult to understand. Last month, a committee of the National Academy of Sciences in Washington released a report. It confirmed that increased about six-tenths of a degree Celsius in the last one hundred years. The report also confirmed evidence that the level of carbon dioxide is increasing.

The best information about climate in the past comes from tests of ice many kilometers deep in Antarctica and Greenland. The tests show changes in temperature during the past four-hundred-thousand years. These tests show that levels of carbon dioxide today are the highest ever measured. These findings have led scientists to believe that carbon dioxide is a major cause of climate warming.

Carbon dioxide is released into the atmosphere when fuel is burned. Oil, coal and wood are all fuels that release the gas. When biological waste breaks down, it also releases carbon dioxide.

However, plants use carbon dioxide in the process called photosynthesis. This process provides food for almost all life on Earth. Some groups that support burning oil and coal want to increase the amount of carbon dioxide in the atmosphere. They oppose international efforts to control carbon dioxide.

Some scientists believe that forests and trees are able to capture large amounts of carbon dioxide from the air. Some groups even suggest carbon dioxide could cause plants to grow faster.

A recent study in North Carolina found that more carbon dioxide in the air could cause trees to grow faster. But the researchers found the effect appears to last for only three years. Another study showed that much of the carbon dioxide that is taken in by trees is released within three years. The study noted that leaves release carbon dioxide when they fall from trees and break down in the soil. Plants also naturally release carbon dioxide through the process of respiration.

The natural balance of gases in the atmosphere is a complex scientific issue. The debate over carbon dioxide is only one part of efforts to understand world climate change.

9 . Rain is vital to life on Earth. However, rain isn’t just made of water anymore—it’s partly made of plastic.

Millions of tiny pieces of plastic, called microplastics, are wandering around Earth’s atmosphere and traveling across entire continents, according to a study published in the journal Proceedings of the National Academy of Sciences on April 12. Another study, published in the journal Science in June 2020, has revealed that every year more than 1,000 tons of the particles (颗粒)—equivalent to over 120 million plastic bottles—fall in rain.

Microplastics are plastic particles less than 5 millimeters in diameter (直径) and come from a number of sources. Plastic bags and bottles released into the environment break down into smaller and smaller bits. Some microplastics are manufactured deliberately to provide abrasion (研磨) in a host of products, such as toothpaste and cleansers, according to the Daily Mail. Another major source is your washing machine. When you wash synthetic (合成的) clothing, tiny microfibers get flushed (冲掉) away with the wastewater. Even though the water is treated by a wastewater plant, the microplastics remain, and they are released into the sea, according to American magazine Wired.

Plastic rain may remind people of acid rain, but the former is far more widespread and harder to deal with. The tiny particles, too small to be seen with the naked eye, are collected by the wind from the ground. They are so light that they stay in the air to be blown around the globe. As they climb into the atmosphere, they are thought to act as nuclei (核心) around which water vapor (水蒸气) condenses (凝结) to form clouds. Some of the dust falls back to land in dry conditions, while the rest comes down as rain, according to the Daily Mail.

Microplastics have been found everywhere you can imagine. From fish and frogs to mice and mosquitoes, their bodies have been found, on average, to contain 40 pieces of microplastic, reported Daily Mail. As the top of the food chain, humans are exposed to microplastics, too. “We live on a ball inside a bubble,” microplastic researcher Steve Allen at University of Strathclyde, Scotland, told Wired. “There are no borders, there are no edges. It (plastic rain) raining on the land and then getting blown back up into the air again, to move somewhere else. There’s no stopping it once it’s out.”