Arctic hottest for 2,000 years
A team of scientists has spent five years studying sediment drawn from
the bottom of Arctic lakes and reconstructed Arctic summer temperatures
using tree rings, glacier ice and lake sediment.
‘Our reconstruction shows that the past half-century was the warmest of the past 2,000 years,’ said Darrell Kaufman, a professor of geology and environmental science at Northern Arizona University. ‘Not only was it the warmest, but it reversed the long-term, millennial-scale trend toward cooler temperatures. The cooling coincided with the slow and well-known cycle in Earth’s orbit around the sun, and it should have continued through the 20th century.’
The Arctic was previously cooling because of the orbital ‘wobble’ that varies the month when the Earth is closest to the sun over thousands of years.
‘The 20th century is the first century for which how much energy we’re getting from the Sun is no longer the most important thing governing the temperature of the Arctic,’ Nicholas McKay, a researcher from the University of Arizona, told BBC News.
November 2009
‘Our reconstruction shows that the past half-century was the warmest of the past 2,000 years,’ said Darrell Kaufman, a professor of geology and environmental science at Northern Arizona University. ‘Not only was it the warmest, but it reversed the long-term, millennial-scale trend toward cooler temperatures. The cooling coincided with the slow and well-known cycle in Earth’s orbit around the sun, and it should have continued through the 20th century.’
The Arctic was previously cooling because of the orbital ‘wobble’ that varies the month when the Earth is closest to the sun over thousands of years.
‘The 20th century is the first century for which how much energy we’re getting from the Sun is no longer the most important thing governing the temperature of the Arctic,’ Nicholas McKay, a researcher from the University of Arizona, told BBC News.
November 2009
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