Water pollution

There are various causes of water pollution.

2 . Yellowstone National Park withdrew more than 10,000 visitors after a flash flood hit the park. Houses, roads and bridges were washed away, and the park’s gateway communities were cut off from roads. Even though scientists and land managers are caught off guard by the flood, unseen in 100 years of recorded history, they recognize the similarities between the situation their data predicted and the flood. They just didn’t expect the flood would occur this year.

While it will take more research to confirm if climate change made this flood event more extreme, the 2021 Greater Yellowstone Climate Assessment predicts significant changes in precipitation (降水), including when it will arrive and what forms it will take. Scientists expect more spring rain and less winter snow. The assessment also predicts increasing annual precipitation in Yellowstone National Park.

Changes have been already documented in the assessment. Since 1950, spring precipitation in the region has increased by 17-23 percent in April and May. Snowfall has dwindled even as overall annual precipitation has increased. That means rather than slowly increasing meltwater flowing to valleys during the summer months, rain tends to combine with melting snow, causing riskier events like the recent flood.

June precipitation this year is now at more than 400 percent above average in the parts of Montana and Wyoming that include Yellowstone National Park. And as temperatures rise, these rain-on-snow events are projected to become more frequent at higher elevations (海拔) in western North America, while lower snowpack will make them less frequent at low elevations.

Bruce Stein, chief scientist of the National Wildlife Federation, said several years ago, when he trained Yellowstone employees for climate planning, they focused on the features that drew visitors to the park — like bison and wolves. Roads, bridges, and houses being washed away was out of their consideration. “I think it’s urgent and necessary for the park to look ahead to plan for different situations that could possibly happen as the climate changes,” said Stein.

3 . Do you know that the oldest tree is a 5, 000-year old bristlecone pine (狐尾松) located in the forests of Nevada? Unfortunately, many of these precious old-growth trees are starting to disappear from our planet. The term old-growth refers to trees that are 150 years or older. This means that many of the trees on the Earth today are younger, smaller, and have shorter lifespans.

As the Earth’s temperature warms up due to climate change, it is having unintended effects on the world’s forests. When temperatures rise, trees close their pores (气孔) to prevent the loss of moisture, and this, in turn, slows down the process of photosynthesis (光合作用). As a result, these trees are shorter and grow slowly, as well as have a high deathrate. Climate change also increases the possibility of droughts and wildfires. After wildfires, it takes a while for the forest ecosystems to recover, and in some cases, the forests are lost permanently. Trees that are stressed are also susceptible (易受影响的) to attacks by bacteria (细菌). Finally, humans have changed the forest landscape through logging (伐木).

There are some who claim that increased greenhouse gas emission is helping trees grow faster because CO₂, is needed for photosynthesis. While some younger trees may benefit from this, we are seeing significantly more loss of forests than gain.

Old-growth forests are a storehouse of carbon, and when they die, the stored CO₂, is released into the air worsening the greenhouse effect. Older forests have higher biodiversity, which is beneficial as each organism has a role to play and there is a wide variety of species. As these forests disappear, species that once called them “home” are forced to relocate, affecting the biodiversity of those ecosystems. Unfortunately, some endangered species are unable to adapt and go extinct.

With trees dying continuously, will future generations miss out on the wonders of forests?

4 . Sam, the four-legged superhero, works to keep a park in Santiago clean. The dog’s superpower? Collecting garbage as a________for visitors.

Sam, who takes regular________in Santiago’s park with his owner, has become________, wearing a green cape (披风) in a comic (连环画) to work as an educational guide.

It________when Sam and Gonzalo Chiang had to stop again and again in the city’s largest green area to________plastic bottles, cans and food packages. “On Sam’s walks, we began to find a lot of________,” Chiang said. “From there, the________to take away the garbage that we found on each visit became apparent. The walk is a good opportunity to________, rather than litter,” Chiang said.

Park officials were impressed and decided to use Sam’s________in its park care campaign. They turned Sam into a cartoon in Sam: The Parquemet Superhero,________visitors to take their waste with them or use________ points found along the path. “This became much more________than expected,” Aravena said. “It reached different schools and has spread very well on social media.”

The________launched anti-litter campaigns last year urging drink vendors (摊主) to switch from plastic cups to glass ones and started________garbage into separate bins.

“Sam and Gonzalo have________us to accelerate (加快) this education process and structure this garbage classification,” said Eduardo Villalobos, the park’s acting director.

6 . A new study says the Amazon rainforest is nearing a tipping point(临界点) in its decline that could see the biologically rich and diverse ecosystem turned into a savannah(热带草原).

“The Amazon is losing its ability to recover from disturbances like drought and extreme weather. Deforestation and climate change are likely the main drivers of this decline,” study co-author Niklas Boers said in a statement. The researchers say they’ve found evidence of this decline across 75 percent of the Amazon.

“It’s worth reminding ourselves that if it gets to that tipping point and we commit to losing the Amazon rainforest, we will get significant feedback on global climate change,” said Timothy Lenton, a scientist and co-author of the study.

The research team looked at three decades’ worth of satellite data, paying close attention to trees and other plants after extreme events. The researchers concluded that the forest, which is essential for oxygen production and carbon sequestration(碳封存), has been losing its resilience for the last two decades.

The researchers say the forest is nearing a tipping point, but the arrival date is unclear as a number of factors can push it closer to or farther from that edge. It’s just too challenging to estimate when the change may occur. But the scientists warn that once the tipping point has been crossed, the change could happen quickly.

The news comes after the Amazon recorded record levels of deforestation in Brazil in January. Animal agriculture is causing deforestation in the Amazon, as Brazil is now the world’s top beef exporter. Last November, the EU took steps to ban beef linked to deforestation. “What we propose is a pioneering initiative,” Virginijus Sinkevicius, the EU environment commissioner, said. “The EU action alone will not solve the problem. We also need major markets like the US to clean up their supply chain.”

8 . Scot Case, Vice President of the environmental marketing firm Terra Choice, was not happy. Case last year sent his researchers into a big-box retail store to evaluate the green advertising claims of some of the products on its shelves. The results were shocking, of the 1,018 products Terra Choice surveyed, all but one failed to live up fully to their green boasts.

He couldn’t believe the result, and had his team redo the survey, but the results came back the same. “It just shows we’re awash in greenwash.” He said.

Many consumers may not have heard the term green washing, but they’ve surely experienced it — misleading marketing about the environmental benefits of a product. Greenwashing isn’t new — ever since the environment was an issue in the early 1970s. As going green has become big business, environmental advocates worry that truly green companies could get lost in the situation.

“We have such a challenge ahead of us on climate change, says Kevin Tuerff, a co-founder of the marketing consultancy EnviroMedia. “Greenwashing harms the effort we need to be making.”

The first step to cleaning up greenwashing is to identify it, and Tuerff and his partners have hit on an innovative way to spotlight particularly abnormal examples. They’ve launched the Greenwashing Index a website that allows consumers to post ads that might be examples of greenwashing and rate them on a scale of 1 to 5 — 1 is a little green lie; S is a big green lie.

It’s a simple device, but it shows the power of the Interne to uncover misleading ads with a simple Web search, any consumer can find out the index they want to know. Googling isn’t the only way to take out the greenwashing, however. The Terra Choice website offers a list of what it calls the “six sins of greenwashing” — six simple signs that should remind consumers of a company that is more interested in selling the earth than saving it.

“We have better green products but a lot of exaggerated (夸张的) claims,” says Case. “That could be enough to destroy the whole green movement” — and that’s not a little green lie.

9 . Bioluminescence (生物发光) is a natural phenomenon wherein a chemical reaction within an organism’s body produces light. It can be found in many places in nature — fireflies, some mushrooms — but mostly in the deep sea.

Recently, Rambouillet, a small historic French town, has teamed up with a company called Glowee to turn the city into a full-scale bioluminescence laboratory. The goal is to change the way in which cities use light. The company uses marine (海的) bacteria harvested from the coast of France. It makes some of the town’s public light up in the cool blue of bioluminescence.

These bioluminescent bacteria are stored in a seawater filled tube, giving the bacteria room to float around and light up. The light provided by the bacteria is part of their natural metabolism, so producing the light requires no energy other than that which is needed to feed the organisms. This makes it much more environmentally friendly and sustainable than electric light, which consumes a huge amount of non-renewable energy.

“On the way to lighting up the world with bioluminescence, you have to feed the bacteria and add water as they grow. That’s not so easy. The phenomenon will be very temperature-dependent and I doubt that it will work in the winter. Also, bioluminescence is not very bright compared to electrical lighting, though they have improved the light intensity,” Carl Johnson, a professor from Vanderbilt University said.

One potential solution to these issues — and one that Glowee is looking into — is to remove the biological aspect of the whole process. Theoretically, luciferase (荧光素酶) can be removed from the bacteria and used to create light instead of the bacteria itself. Because luciferase is non-living, it doesn’t need to be fed. Creating new means of sustainable lighting is a way of being environmentally friendly without plunging the earth back into darkness.