Even minor changes in behavior can have a positive environmental impact. Therefore, it is suggested to remove or reduce single-use plastic bags from your shopping trips, because the bags break down slowly, causing them to linger in landfills. But how long does a plastic bag really stick around?

The Center for Biological Diversity estimates that it takes a bag roughly 1000 years to break down. The term “break down” is a little misleading, though. Plastic ends up photodegrading (光降解) from ultraviolet (紫外线) radiation because the majority of microorganisms cannot eat it. And even after the bags degrade, the micro-plastics they leave behind may still harm the environment.

While 1000 years seems long, it is only an estimate. Since the invention of plastic bags in the 1950s or so, humankind has never actually seen the substance break down in real time. Instead, scientists have adopted respirometry tests (呼吸运动测量法), which helps estimate the breakdown rate of an organic substance by measuring the CO₂ that the microorganisms produce when breaking down the material. When an organic substance, such as food waste, is present, CO₂ levels rise, which allows scientists to estimate the rate of breakdown. However, because plastic bags don’t produce any CO₂,—microorganisms aren’t eating them, the bags are just sitting there. If buried in a landfill and sheltered from ultraviolet light, plastic bags will last a very long time.

Bags have an impact on the environment beyond just their removal. It takes fossil fuels to make bags; one estimate puts this amount at 12 million barrels (桶) of oil annually. And after a bag has served its purpose in a consumer’s hands, it may then enter the food chain for wildlife. Plastic that builds up along the food chain is consumed by creatures like birds and fish.

While reducing the use of plastic bags is a good idea, choosing a cloth bag might not be the habit that will help the environment the most. The carbon footprint left by the cloth bags must be countered by thousands of uses.

Conversation around sustainability (可持续发展) has been growing in recent years, with a whole wave of new words entering the dictionary to describe its influence across many topics. To honour Earth Day, we’re exploring the developing language of sustainability in our day-to-day lives.

The climate emergency took on new meanings in 2018 thanks to climate activist Greta Thunberg. Her speeches and strikes lighted a global conversation and since then, we’ve seen many climate-related words entering the Collins Word of the Year shortlists including “rewilding” and “climate anxiety”. We also saw two climate words win CollinsWOTY: single use (2018) and climate strike (2019).

This increased everyday conversation around our planet also means we’re seeing new words enter the dictionary on an ongoing basis. Recent entries include climate justice (正义), the formulation of policies (政策的制定) to fight climate change that do not place an unfair pressure on poorer and local communities, and zero waste, a situation in which people’s activities produce nothing that cannot be reused, re-purposed, or recycled.

The more we talk about the climate crisis, the more forced we are to find solutions. This means we’re seeing new language around energy production. One example is solar park, which is an area of land that has been set aside for the generation of solar energy. Solar parks are a renewable energy source that can reduce carbon emissions (碳排放). Other energy-related words include blue hydrogen (氢) and green hydrogen, new entries to the Collins Dictionary, both described as a commercially produced hydrogen that creates little to no emissions of CO_2.

Fighting the climate crisis depends on big businesses and governments using greener practices. But there are lots of ways we can protect our planet as individuals and these little changes have led to developing words around nature, diet, and lifestyle.

A robot the size of a large bulldozer (推土机) moves along the bottom of the deep sea. It eats metallic (含金属的) rock and soft mud. The stuff travels up a long pipe to a ship, where workers and machinery separate out the rock and throw the mud back into the ocean. This is a mining operation. The rock contains a mixture of metals, including ones called rare earth metals. People use these materials to make batteries and electronics like computers and phones.

Deep-sea mining hasn’t happened yet. But it probably will occur within the next decade. No country owns any part of the deep sea. So an organization called the International Seabed Authority (ISA) decides who is allowed to mine there. The ISA has allowed 29 organizations to explore the deep sea and make plans for mining. One company plans to begin mining in the year 2027.

Scientists and environmentalists, though, warn that mining could destroy deep-sea ecosystem. In 1989, ecologist Hjalmar Thiel carried out a test. His team searched the seafloor of the Pacific Ocean, in a spot with lots of the metallic rocks that miners want. They didn’t actually collect any of the rocks. But they disturbed the mud, just as a mining operation would. The plume (飘升之物) of mud fell back down over the ocean floor burying creatures living there. As of 2015, the area they disturbed had not recovered. Signs of the search are still there. Sponges (海绵动物), corals, and other animals have not moved back in. That means mining could have harmful, long-lasting consequences for deep ocean life. Scientists want to understand the deep sea better before disturbing it.

Leaving the deep sea alone sounds great, but people need those metals. “Mines on land are soon going to run out,” geologist Steven Scott of the University of Toronto told Smithsonian Magazine, “Every electronic device in the world has rare earth metals in it…we need raw resources.” New energy technologies including solar and wind power and electric cars, rely on these metals as well. We may need to mine them from the sea in order to switch to greener energy sources.