John on March 21, 2007 at 12:01 am
Man, did I pick the right moment to become a global warming skeptic. There’s a bumper crop of bad news for GW promoters these days. And the beat goes on, this time courtesy of NASA:
Scientists have traditionally relied upon indirect data gathering methods to study climate in the Earth’s past, such as drilling ice cores in Greenland and Antarctica. Such samples of accumulated snow and ice drilled from deep within ice sheets or glaciers contain trapped air bubbles whose composition can provide a picture of past climate conditions. Now, however, a group of NASA and university scientists has found a convincing link between long-term solar and climate variability in a unique and unexpected source: directly measured ancient water level records of the Nile, Earth’s longest river.
“Since the time of the pharaohs, the water levels of the Nile were accurately measured, since they were critically important for agriculture and the preservation of temples in Egypt,” she said. “These records are highly accurate and were obtained directly, making them a rare and unique resource for climatologists to peer back in time.”
A similarly accurate record exists for auroral activity during the same time period in northern Europe and the Far East. People there routinely and carefully observed and recorded auroral activity, because auroras were believed to portend future disasters, such as droughts and the deaths of kings.
The researchers found some clear links between the sun’s activity and climate variations. The Nile water levels and aurora records had two somewhat regularly occurring variations in common – one with a period of about 88 years and the second with a period of about 200 years.
This is not the same argument being made by the author of The Chilling Stars, but it is similar in that both posit changes in the sun’s output as fundamental to global climate change.
[HT: Bryan at HotAir]
Category: Science & Tech |