By Dennis T. Avery, Hudson Institute
Saturday, July 7, 2007
Another scientist has added his voice to the Global Warming debate. Canadian climatologist Tim Patterson says the sun drives the earth's climate changes--and Earth's current global warming is a direct result of a long, moderate 1,500-year cycle in the sun's irradiance.
Patterson says he learned of the 1,500-year climate cycle while studying cycles in fish numbers on Canada's West Coast. Since the Canadian West had no long-term written fishery records, Patterson's research team drilled sediment cores in the deep local fjords to get 5,000-year climate profiles from the mud. The mud showed the past climate conditions: Warm summers left layers thick with one-celled fossils and fish scales. Cold, wet periods showed dark sediments, mostly dirt washed from the surrounding land.
Patterson's fishing profiles clearly revealed the sun's 87 and 210-year solar cycles--and the longer, 1500-year Dansgaard-Oeschger cycles found since the 1980s in ice cores, tree rings, and fossil pollen.
"Our finding of a direct correlation between variations in the brightness of the sun and earthly climate indicators is not unique," says the climatologist from Carleton University. "Hundreds of other studies, using proxies from tree rings in Russia's Kola Peninsula to water levels of the Nile, show exactly the same thing: The sun appears to drive climate change."
But there was a problem. By themselves, the variations in solar irradiation were too small to account for the big variations his research team found in the Canadian fish catches.
"Even though the sun is brighter now than at any time in the past 8,000 years, the increase in direct solar input is not calculated to be sufficient to cause the past century's modest warming on its own. There had to be an amplifier of some sort for the sun to be a primary driver of climate changes. Indeed, that is precisely what has been discovered," says Patterson.
"In a series of groundbreaking scientific papers starting in 2000, Vizer, Shaviv, Carslaw and most recently Svensmark et al., have collectively demonstrated that as the output of the sun varies . . . varying amounts of galactic cosmic rays from deep space are able to enter our solar system. . . . These cosmic rays enhance cloud formation, which, overall, has a cooling effect on the planet."
"When the sun is less bright, more cosmic rays are able to get through to Earth's atmosphere, more clouds form and the planet cools. . . . This is precisely what happened from the middle of the 17th century into the early 18th century, when the solar energy input to our atmosphere . . . was at a minimum and the planet was stuck in the Little Ice Age."
The Canadian expert concludes, "CO2 variations show little correlation with our planet's climate on long, medium and even short time scales." Instead, Earth's sea surface temperatures show a massive 95 percent lagged correlation with the sunspot index.
Patterson says climate change is the most complex field we've ever studied. He notes that a 2003 German poll of 530 scientists from 27 countries found two-thirds of the respondents doubted that "the current state of scientific knowledge is developed well enough to allow for a reasonable assessment of the effects of greenhouse gases."
Attempting to stop global warming with the Kyoto Protocol, he warns, could be as useless as King Canute commanding the tides to cease..