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

（单词翻译）

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