Research press release


Nature Geoscience

Runaway greenhouse revised


Colin Goldblattら等は数値モデルを用いて、太陽放射の吸収量と地球表面と大気により放射される熱輻射との釣り合いを計算した。彼らは、今日の地球が受けている太陽放射と同様の量を受けている惑星でも温室効果の暴走が起こりうることを見つけた。より複雑な大気モデルが必要ではあるが、彼らは(高レベルの温室効果ガスと少ない雲などの)特定の大気条件下では安定して温暖な地球は暴走した温室効果の状態に変化しうると示唆している。しかしながら、著者等は、近い将来に予測されている人工的な温室効果ガスの放出は、地球でそのような温室効果の暴走の引き金となるには不十分であると述べている。

A runaway greenhouse effect, in which a planet heats up uncontrollably and the oceans evaporate, may be easier to initiate than previously thought, reports a study published online this week in Nature Geoscience. A stable temperate climate (such as that enjoyed by Earth) and a runaway greenhouse effect are both possible outcomes for a planet that receives the same level of solar radiation as the Earth today. It was previously thought that the amount of solar radiation required for a runaway greenhouse effect was higher.

Colin Goldblatt and colleagues used numerical models to calculate the balance between solar radiation absorbed and thermal radiation emitted by the Earth’s surface and atmosphere. They find that a runaway greenhouse effect is possible for a planet receiving a similar amount of solar radiation as the Earth does today. Although more complex atmospheric models are still needed, they suggest that under certain atmospheric conditions - such as high levels of greenhouse gases and few clouds - a stable temperate Earth could transition to a runaway greenhouse state. However, the authors note that projected anthropogenic greenhouse gas emissions in the near future are insufficient to trigger such a runaway greenhouse effect on Earth.

doi: 10.1038/ngeo1892


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