Regular wobbles in the Earth's tilt were responsible for the global warming episodes that interspersed prehistoric ice ages, according to new evidence. The finding is the result of research led by Russell Drysdale of the University of Newcastle that has been able to accurately date the end of the penultimate ice age for the first time.
Regular wobbles in the Earth's tilt were responsible for the global warming episodes that interspersed prehistoric ice ages, according to new evidence.
The finding is the result of research led by Russell Drysdale of the University of Newcastle that has been able to accurately date the end of the penultimate ice age for the first time.
!ADVERTISEMENT!
The new dates, which appear in the today's edition of Science, show the end of the second last ice age occurring 141,000 years ago, thousands of years earlier than previously thought.
Using information gathered from a trio of Italian stalagmites, the research has punched a hole in the prevailing theory that interglacial periods are related to changes in the intensity of the northern hemisphere summer.
Drysdale and colleagues suggest that the Earth emerges from ice ages due in large part to changes in the tilt of the planet in relation to the sun, otherwise known as its obliquity. This affects the total amount of sunlight each hemisphere receives in its respective summer, rather than the peak intensity of the solar radiation during the northern summer.
Sediment on the sea floor contains accurate a record of what happened to the Earth's climate prior to the last ice age. But up until now dating the sediment and the evident climatic changes has not been possible.
Article continues: http://dsc.discovery.com/news/2009/08/14/earth-wobble-climate.html
