Carbon dioxide is the chief greenhouse gas produced by human activity. It is produced when we burn fossil fuels: oil, gas and coal.
二氧化碳是人类活动产生的主要温室气体,在我们燃烧石油,天然气,煤这些矿物燃料时产生。
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The gas, which is not covered by existing regulations to protect ozone, is now the largest ozone-depleting substance produced by human activity, the research shows.