Study Suggests Melting in Arctic Could Release Heat-trapping Gases

A new study suggests that increased warming in Arctic areas could release huge amounts of carbon into the atmosphere.

The study centered on the permafrost layer beneath Arctic soil. The researchers said melting of this layer could release billions of tons of carbon into the atmosphere, with big effects on worldwide temperatures.

Permafrost is a layer of soil in the world's Arctic and Antarctic areas. It has, in some cases, remained frozen for many years. Permafrost is important to the world's climate because it is believed to store two times the amount of carbon as there is in the atmosphere.

The study was published this month in the science journal Nature Geoscience. Researchers examined how the top layer of this frozen soil warms during the summer. That is when plants and microorganisms come to life. The microorganisms eat plant roots and "breathe" like all living organisms, releasing carbon dioxide which is considered a heat-trapping, greenhouse gas. Scientists call this process rhizosphere priming.

The researchers say as more frozen soil warms up, more plant roots are becoming exposed to microorganisms. As a result more carbon dioxide is being released. The researchers estimated the process could add as much as 40 billion tons of carbon to the atmosphere by the year 2100.

Until now, the United Nations Environment Programme had estimated that global emissions² of carbon gases must fall by 7.6 percent every year for the next 10 years. That is what scientists say would be needed to prevent world temperatures from rising more than 1.5 degrees Celsius³ –the main temperature goal of the Paris Agreement.

But the writers of the new study note that their estimates are currently "unaccounted for" in global emission¹ predictions. "To keep warming below 1.5 or 2 °C," the authors wrote, emissions "may need to be even more constrained⁵."

Researchers suggest that warming in the Arctic is worse than in other places. Studies by the United States space agency and the U.S. National Oceanic and Atmospheric⁶ Administration suggest that the past 10 years have been the hottest on record. In the Arctic, air temperatures are rising two times as fast as the global average.

I'm John Russell.

Words in This Story

permafrost – n. technical : a layer of soil that is always frozen in very cold regions of the world

emission -- n. something sent out or given off

unaccounted – adj. unexplained, not included in; the act of producing or sending out something (such as energy or gas) from a source

prediction – n. the action of saying something will happen; a forecast

constrain⁴ – v. to limit or restrict the scope or activity of something

1 emission   

n.发出物，散发物；发出，散发

参考例句：

• Rigorous measures will be taken to reduce the total pollutant emission.采取严格有力措施，降低污染物排放总量。
• Finally,the way to effectively control particulate emission is pointed out.最后，指出有效降低颗粒排放的方向。

2 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

3 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

4 constrain   

vt.限制，约束；克制，抑制

参考例句：

• She tried to constrain herself from a cough in class.上课时她竭力忍住不咳嗽。
• The study will examine the factors which constrain local economic growth.这项研究将考查抑制当地经济发展的因素。

5 constrained   

adj.束缚的,节制的

参考例句：

• The evidence was so compelling that he felt constrained to accept it. 证据是那样的令人折服，他觉得不得不接受。
• I feel constrained to write and ask for your forgiveness. 我不得不写信请你原谅。

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。