WASHINGTON, U.S.A. - Worldwide levels of the chief greenhouse gas that causes
global warming have hit a milestone, reaching an amount never before
encountered by humans, federal scientists said.
Carbon dioxide was measured at 400 parts per million at the oldest
monitoring station which is in Hawaii sets the global benchmark. The
last time the worldwide carbon level was probably that high was about 2
million years ago, Pieter Tans of the National Oceanic and Atmospheric
Administration said on Friday.
That was during the Pleistocene Era. “It was much warmer than it is
today,” Tans said. “There were forests in Greenland. Sea level was
higher, between 10 and 20 metres.”
Other scientists say it may have been 10 million years ago that Earth
last encountered this much carbon dioxide in the atmosphere. The first
modern humans only appeared in Africa about 200,000 years ago.
The measurement was recorded Thursday and it is only a daily figure, the
monthly and yearly average will be smaller. The number 400 has been
anticipated by climate scientists and environmental activists for years
as a notable indicator, in part because it’s a round number — not
because any changes in man-made global warming happen by reaching it.
Source: Yahoo News...More
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