VOA慢速英语--Study: Warmer Soil Releasing More Carbon

 

Even the dirt on the ground is likely making climate change worse, a new study finds. Researchers have shown that warmer temperatures are heating the soil, which is causing microbes to become more active and release more of the soil’s carbon into the atmosphere.

Ben Bond-Lamberty of the Joint¹ Global Change Research Institute is the lead author of the study. He says, “These soil changes can potentially contribute to even higher temperatures.”

The findings were published on August 2 in the journal Nature.

What the study showed

Scientists studied device readings, soil measurements, plant growth details and satellite observations from around the world. Their work is the most complete study yet on the subject.

They found a sharp increase in carbon released into the atmosphere by bacteria and fungi² in soil from 1990 through 2014. Researchers explain that the carbon comes from the dead plants and leaves the microbes eat. As temperatures rise, the microbes eat more. And the more they eat, the more carbon they make into carbon dioxide and release into the atmosphere.

This uncontrolled cycle speeds up and intensifies³ climate change, says Jerry Melillo of Marine⁴ Biological Laboratory in Massachusetts. Melilo was not part of the study.

How do fossil fuels fit in?

Overall, soil releases about nine times more carbon than human-caused activities. But that is part of a natural cycle: The amount of carbon released into the air is about equal to the carbon oceans and plants take in.

However, carbon released from fossil fuel causes an imbalance. Burning coal, oil and natural gas puts more carbon into the atmosphere than nature can take out. The additional carbon heats the air and soil. And as the air and soil get hotter, the earth will release yet more carbon that it has been holding.

If something isn't done, "we are really in trouble," said Rattan⁵ Lal of Ohio State University, who wasn't part of the study.

He added that proper soil conservation can help keep more carbon in soil. Conservation methods include avoiding turning the soil, covering off-season crops and leaving crop deposits on the ground.

I’m Alice Bryant.

Words in This Story

climate change – n. a change in the world’s climate patterns attributed largely to the increased levels of atmospheric⁶ carbon dioxide produced by the use of fossil fuels

microbe – n. an extremely small living thing that can only be seen with a microscope

author – n. a person who has written something

fungus⁷ – n. any one of a group of living things that often look like plants but live on dead or decaying things (plural: fungi)

carbon dioxide – n. a gas that is produced when people and animals breathe out or when fossil fuels are burned and that is used by plants for energy

cycle – n. a set of events or actions that happen again and again in the same order?

fingerprint⁸ – n. a distinctive or identifying mark or characteristic

1 joint   

adj.联合的，共同的；n.关节，接合处；v.连接，贴合

参考例句：

• I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤，肩膀脫臼了。
• We wrote a letter in joint names.我们联名写了封信。

2 fungi   

n.真菌，霉菌

参考例句：

• Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
• The lawn was covered with fungi.草地上到处都是蘑菇。

3 intensifies   

n.（使）增强， （使）加剧( intensify的名词复数 )v.（使）增强， （使）加剧( intensify的第三人称单数 )

参考例句：

• A clear atmosphere intensifies the blue of the sky. 纯净的空气使天空变得更蓝。 来自《简明英汉词典》
• Blowing on fire intensifies the heat. 吹火使热度加强。 来自《简明英汉词典》

4 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

5 rattan   

n.藤条，藤杖

参考例句：

• When they reached a long bridge fastened with rattan strips,everyone got out and walked.走到那顶藤条扎的长桥，大家都下车步行。
• Rattan furniture,include rattan chair,rattan table,and so on.藤器家具包括藤椅藤桌等等。

6 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

7 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

8 fingerprint   

n.指纹；vt.取...的指纹

参考例句：

• The fingerprint expert was asked to testify at the trial.指纹专家应邀出庭作证。
• The court heard evidence from a fingerprint expert.法院听取了指纹专家的证词。