Ice cores unlock climate secrets
BBC 9 June, 2004
Global climate patterns stretching back 740,000 years have been confirmed by a three-kilometre-long ice core drilled from the Antarctic, Nature reports.
Analysis of the ice proves our planet has had eight ice ages during that period, punctuated by rather brief warm spells - one of which we enjoy today.
If past patterns are followed in the future, we can expect our "mild snap" to last another 15,000 years.
The data may also help predict how greenhouse gases will affect climate.
Initial tests on gas trapped in the ice core show that current carbon dioxide (CO2) levels are higher than they have been in 440,000 years.
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"There is great controversy as to whether human beings have changed the climate," said Professor McManus. "But there is no doubt about the fact that human beings have changed the Earth's atmosphere. The increased levels of greenhouse gases are geologically incredible."
He added: "It is something of grave concern to someone like me, who sees the strong connection between greenhouse gases and climate in the past."
http://news.bbc.co.uk/2/hi/science/nature/3792209.stm