VOA慢速英语--科学家列出四种捕获碳的方法 限制气温上升（在线收听）

Scientists List Four Ways to Capture Carbon, Limit Rising Temperatures

A new report suggests four simple ways to remove carbon dioxide from the atmosphere.

Carbon dioxide is among the gases linked to the increase in the Earth’s temperature.

The National Academies of Sciences, Engineering and Medicine published the report.

All four methods to take carbon from the air and store it use natural processes.

However, all of them still would not be enough to prevent possible catastrophic levels of climate change, the report said.

Climate scientists say carbon emissions from burning fossil fuels have warmed the Earth’s atmosphere by about 1 degree. At the current rate, temperatures will likely increase by 1.5 degrees by 2050. That warning is from a new report by the United Nations Intergovernmental Panel on Climate Change.

Technologies that create no emissions, like wind or solar power, will not be enough to stop climate change, the U.N. report said. It called for technologies that take carbon dioxide out of the air.

The group of experts with the National Academies of Sciences considered existing methods for removing carbon dioxide from the atmosphere.

The first of the four is one that almost everyone knows already: planting trees.

It’s not really a technology, admitted Princeton University biologist Stephen Pacala. He headed the group of scientists.

The second method is also simple: take better care of existing forests. These are the two least costly ways to get large amounts of carbon out of the air, the report said.

Farms offer the next biggest and least costly carbon dioxide removal method.

Soil that is used to grow crops too much loses carbon and nutrients. Rebuilding the soil increases its ability to hold water and makes it more fertile.

The carbon comes from the atmosphere," Pacala said, and he added, "We know how to do quite a bit of this."

The fourth method, the report said, is known as biomass energy with carbon capture and storage, or BECCS. BECCS involves burning some kind of plant matter to produce electricity, fuel or heat, then capturing and storing the carbon gasses in underground containers.

The report said BECCS could remove the largest amount of carbon dioxide from the air, but is also the most costly.

If used worldwide, these four techniques could remove up to 10 gigatons of carbon dioxide from the atmosphere each year.

It is estimated that 50 gigatons of carbon are produced each year around the world.

The scientists said that using more land for carbon dioxide removal would mean taking land needed to produce crops.

The scientists also considered new technologies that capture carbon dioxide from the air.

For example, one method would use the ability of some naturally existing minerals that react with carbon dioxide to store it. But the scientists said this method is not well understood.

I’m Susan Shand.

Words in This Story

atmosphere – n. the whole mass of air that surrounds the Eart

catastrophic – adj. a terrible disaster

emission – n producing or sending out something (such as energy or gas) from a source

fossil fuels – n. a fuel such as coal, oil, or natural gas that is formed in the earth from dead plants or animals

biomass – n. organic matter used as a fuel, especially in a power station for the generation of electricity.

gigaton – n. a unit of explosive force equal to one billion tons of TNT