Aging forests emit carbon老龄化森林成为“碳源”

李召新

美国农业部的一份新报告称，美国森林碳储量持续增长，森林在未来可能会加剧全球变暖，而非缓解全球变暖，到2070年，美国的森林大部分可能转化为“主要碳源”。

主题语境：环境 篇幅：342词 建议用时：6分钟

1 According to a new USDA （the US Department ofAgriculture） report， US forests could worsen globalwarming because they are being destroyed by naturaldisasters and are losing their ability to absorbplanet?warming gases as they get older. The reportpredicts that the ability of forests to absorb carbonwill start declining after 2025 and that forests couldrelease up to 100 million metric tons of carbon a yearas their emissions from decaying （腐烂） trees go above their carbon absorption. Forestscould become a“ substantial carbon source” by 2070， the USDA report says.

2 The loss of carbon absorption is driven in part by natural disasters such as wildfire，tornadoes and hurricanes， which are increasing in frequency and strength as globaltemperatures rise. The disasters destroy forestland， destroying its ecosystem anddecreasing its ability to absorb carbon， according to Lynn Riley， a senior manager ofclimate science at the American Forest Foundation. Aging forests also contribute. Thereport finds that older mature trees absorb less carbon than younger trees of the samespecies， and US forests are rapidly aging.

3 This trend is likely to continue， as forests come under increasing threat from climatechange and exploitation （开采）. The typical tropical forest may become a carbon sourceby the 2060s， according to Simon Lewis， a professor in the school of geography atUniversity of Leeds“. Humans have been lucky so far， as tropical forests are cleaning uplots of our pollution， but they can＇t keep doing that indefinitely，” he said“. We need to cutdown fossil fuel emissions before the global carbon cycle starts working against us.”

4 US forests currently absorb 11 percent of US carbon emissions， or 150 million metrictons of carbon a year， equal to the combined emissions from 40 coal power plants， accordingto the report. The loss of forests as natural carbon absorbers will require the USto cut emissions more rapidly to reach net zero.“ As we work to decarbonize （脫碳）， forestsare one of the greatest tools. If we were to lose that tool， it means we will contributethat much more in emissions，” Riley said.

Reading Check

Detail

1. What is the main finding of the report？

A. Forests are suffering from decaying trees.

B. Forests could contribute to global warming.

C. Forests are being destroyed by natural disasters.

D. Forests have become substantial carbon absorbers.

Gist

2. What is paragraph 2 mainly about？

A. The key role of forests in the ecosystem.

B. The consequences of frequent natural disasters.

C. The impact of rising global temperatures on forests.

D. The reasons for forests declining ability to absorb carbon.

Detail

3. What is Simon Lewis suggestion on addressing the problem？

A. Reducing fossil fuel emissions.

B. Cleaning up decaying trees in time.

C. Planting trees on a large scale.

D. Limiting the exploitation of forests.

Inference

4. What does the author intend to do in the last paragraph？

A. Offer suggestions on forest management.

B. Stress the significance of forest protection.

C. Present the efforts made to reach net zero.

D. Show the carbon emissions from coal power plants.

Language Study

Ⅰ. Difficult sentence in the text

The loss of carbon absorption is driven in part by natural disasters such as wildfire，tornadoes and hurricanes， which are increasing in frequency and strength as global temperaturesrise. 碳吸收的損失部分是由野火、龙卷风和飓风等自然灾害造成的，随着全球气温的上升，这些灾害的频率和强度都在增加。

【点石成金】本句是一个复合句。which引导的是一个非限制性定语从句，as引导的是一个时间状语从句。

Ⅱ. Text?centered chunks

up to 多达

increase in 在……方面增加

in part 部分地；在某种程度上

be likely to 有可能……

so far 到目前为止

clean up 清理

cut down 减少；削减

be equal to 等于