Aging forests emit carbon老齡化森林成為“碳源”

李召新

美國農業部的一份新報告稱，美國森林碳儲量持續增長，森林在未來可能會加劇全球變暖，而非緩解全球變暖，到2070年，美國的森林大部分可能轉化為“主要碳源”。

主題語境：環境 篇幅：342詞 建議用時：6分鐘

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 （腐爛） 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 （開采）. 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、龍卷風和颶風等自然災害造成的，隨著全球氣溫的上升，這些災害的頻率和強度都在增加。

【點石成金】本句是一個復合句。which引導的是一個非限制性定語從句，as引導的是一個時間狀語從句。

Ⅱ. Text?centered chunks

up to 多達

increase in 在……方面增加

in part 部分地；在某種程度上

be likely to 有可能……

so far 到目前為止

clean up 清理

cut down 減少；削減

be equal to 等于