坎布里奇—大气层上一次含二氧化碳量与今天一样多大约出现在三百万年前 — — 当时的海平面比今天高10—30米。
CAMBRIDGE – The last time the atmosphere held as much carbon dioxide as it does today was about three million years ago – a time when sea levels were 10-30 meters higher than they are now.