Volcanic carbon dioxide in Earth's early atmosphere kept Earth warm enough for life to begin during the time when the Sun was too dim to provide much warmth.
地球早期大气中的火山二氧化碳使地球足够温暖，保证生命在太阳过于昏暗而无法提供足够热量的时候能够得以孕育。
At the same time, nearly half of U.S. carbon emissions come from heating, cooling and powering our homes, offices and other buildings.
与此同时，美国人近一半的碳排放来自供暖、制冷以及为家庭、办公室和其他建筑供电。
But at the same time, nearly half of U.S. carbon emissions come from heating, cooling and powering our homes, offices and other buildings.
但与此同时，美国人近一半的碳排放来自供暖、制冷以及为家庭、办公室和其他建筑供电。
The unprecedented land clearance released vast quantities of carbon dioxide into the atmosphere, triggering for the first time humanly caused global warming.
空地的规模史无前例，它们将大量的二氧化碳气体释放到了大气中，因而引发了第一次人为导致的全球变暖。
Last time we talked about photosynthesis, the process by which plants use light to convert carbon dioxide and water into food.
上次我们讨论了光合作用，即植物利用光将二氧化碳和水转化为食物的过程。
When Stevenson followed the carbon-14 trail back in time, he found carbon-14 levels change with the intensity of solar burning.
当史蒂文森依据碳-14的痕迹追溯过去时，他发现碳-14的含量随着太阳燃烧的强度而变化。
Simulations of the collision suggest that Earth really did melt for a brief time, meaning that all lightweight materials like carbon and water would have been utterly vaporized.
对这次撞击的模拟显示地球确实在短暂的时间内融化了，这意味着像碳和水这样的轻质物质都会完全蒸发掉。
But it will take time to learn how to capture carbon.
但我们需要时间来学习如何进行碳捕获。
While black carbon particles tend to settle over time and do not have the global reach of greenhouse gases, they do travel, scientists now realize.
当黑炭颗粒随着时间漫延，它们不象温室气体那样有着全球性的分步，科学家们发现它们会漂移。
Our goal is to help prevent traffic accidents, free up people's time and reduce carbon emissions by fundamentally changing car use.
我们的目标是要从根本上改变汽车的使用方式，减少交通事故，为人们腾出时间，减少碳排放。
And that extra carbon takes a long time to drain out of the tub.
而剩下的碳要从“浴缸”里排出去需要较长的时间。
The method is more efficient than others because it adds two carbon atoms at a time, rather than one, to the hydrocarbon molecules being formed.
这种方法比其他的更有效，因为它向构造中的碳氢化合物一次引入两个碳原子而不是一个。
Certainly we are having a difficult time reducing our levels of carbon emissions, meeting previous goals on biodiversity, and eliminating Marine, atmospheric, and terrestrial pollution.
当然，我们还有不同的时间去提高减少碳的排放量的水平，以前的会议的目标是要保持生物的多样化，消除海洋大气陆地上的污染物。
This time, it is carbon isotopes that give the game away.
这一次是碳同位素泄露了秘密。
Plus, eating fresh food means it probably spent less time travelling, which saves enormous amounts of oil and carbon dioxide emissions.
此外，吃新鲜食品意味着可能减少运输的时间，那是对石油和二氧化碳排放的减少的贡献。
But with the new nanotube devices, the Chambers would have to be replenished with carbon dioxide and water from time to time to keep the reaction going.
但是对于这个新的纳米管装置，需要不断向仪器内通入二氧化碳和水来维持反应的继续。
And, this is all that was known at that time, seven metals, carbon, and sulfur.
这是当时所知道的了，7种金属，碳，和硫磺。
"You go along a core and everything's the same, the same, the same, and then suddenly you pass this time line and the carbon chemistry is completely different," Dickens said.
“你偏离了核心，所有的东西都是一样的，突然间你过了时间轴，碳化学已经是完全不同了，”Dickens说。
Because the tax started low and its rises were set out in advance, businesses had plenty of time to make plans to cut their carbon use.
正因为该税的税额开始较低且提前公布了增幅，使得企业有足够的时间来制定计划以减少其碳用量。
So far, the rise in carbon dioxide seems to be fairly smooth over time, but the change in vegetation is jerkier.
到目前为止，似乎二氧化碳随着时间变化而增加的幅度相当平稳，但植被的变化却有更大的波动。
Instead, they know how to use sunlight to convert atmospheric carbon into oil in real time.
代之的是，他们可以利用阳光将大气中的碳实时转换成燃油。
Lake sediment nevertheless constitutes an important "carbon sink," serving to store - sometimes for a very long time - a significant portion of the carbon-containing material that does not decompose.
然而湖泊沉积物又是一个重要的“碳汇”，用来存储-有时存储很长的时间-相当大部分不能分解的含碳物质。
The tiny, multitalented carbon tubes can carry single molecules, one at a time.
这种微小的，多才多艺的碳纳米管可以一次运输一个单分子
There's even senses of time, itching, hunger, and blood carbon dioxide levels, just to name a few — and there are up to 20.
甚至还有时间感，痒感，饥饿感和血液二氧化碳含量，这里只列出了一小部分，有多达20种感觉。
Large populations of this organism, sustained over long periods of time, could significantly lower atmospheric carbon dioxide levels and, in turn, lower average temperatures.
大规模的浮游植物种群，如果持续时间较长，就能够明显降低大气二氧化碳的水平，从而相应降低平均气温。
With the right incentives, they can pursue economic growth and at the same time, move to a lower carbon economy.
如果能采取正确的激励措施，它们就可以在实现增长的同时向低碳经济转变。
With the right incentives, they can pursue economic growth and at the same time, move to a lower carbon economy.
如果能采取正确的激励措施，它们就可以在实现增长的同时向低碳经济转变。
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