Blogger Al Fin (Hat tip: Andrew Stuttaford) recently identified reports concerning the opinions of Professor Nigel Weiss (Cambridge University) and Habibulo Adusamatov (St. Petersburg) on just this subject.
Dr. Weiss believes that man-made greenhouse gases have recently had a role in warming the earth, although the extent of that role, he says, cannot yet be known. What is known, however, is that throughout earth's history climate change has been driven by factors other than man: "Variable behaviour of the sun is an obvious explanation," says Dr. Weiss, "and there is increasing evidence that Earth's climate responds to changing patterns of solar magnetic activity."
The sun's most obvious magnetic features are sunspots, formed as magnetic fields rip through the sun's surface. A magnetically active sun boosts the number of sunspots, indicating that vast amounts of energy are being released from deep within.
Typically, sunspots flare up and settle down in cycles of about 11 years. In the last 50 years, we haven't been living in typical times: "If you look back into the sun's past, you find that we live in a period of abnormally high solar activity," Dr. Weiss states.
These hyperactive periods do not last long, "perhaps 50 to 100 years, then you get a crash," says Dr. Weiss. 'It's a boom-bust system, and I would expect a crash soon."
In addition to the 11-year cycle, sunspots almost entirely "crash," or die out, every 200 years or so as solar activity diminishes. When the crash occurs, the Earth can cool dramatically. Dr. Weiss knows because these phenomenon, known as "Grand minima," have recurred over the past 10,000 years, if not longer.
"The deeper the crash, the longer it will last," Dr. Weiss explains. In the 17th century, sunspots almost completely disappeared for 70 years. That was the coldest interval of the Little Ice Age, when New York Harbour froze, allowing walkers to journey from Manhattan to Staten Island, and when Viking colonies abandoned Greenland, a once verdant land that became tundra. Also in the Little Ice Age, Finland lost one-third of its population, Iceland half.
Professor Adusamatov ("head of the space research laboratory at the St. Petersburg-based Pulkovo Observatory") suggests that increasing levels of carbon dioxide in the atmosphere are not the cause, but rather an effect produced by global warming.
He notes that the world's oceans are not actually warming:
"Global warming results not from the emission of greenhouse gases into the atmosphere, but from an unusually high level of solar radiation and a lengthy - almost throughout the last century - growth in its intensity," Abdusamatov told RIA Novosti in an interview.
"It is no secret that when they go up, temperatures in the world's oceans trigger the emission of large amounts of carbon dioxide into the atmosphere. So the common view that man's industrial activity is a deciding factor in global warming has emerged from a misinterpretation of cause and effect relations."
Abdusamatov claimed that the upper layers of the world's oceans are - much to climatologists' surprise - becoming cooler, which is a clear indication that the Earth has hit its temperature ceiling already, and that solar radiation levels are falling and will eventually lead to a worldwide cold spell.
"Instead of professed global warming, the Earth will be facing a slow decrease in temperatures in 2012-2015. The gradually falling amounts of solar energy, expected to reach their bottom level by 2040, will inevitably lead to a deep freeze around 2055-2060," he said, adding that this period of global freeze will last some 50 years, after which the temperatures will go up again.
"There is no need for the Kyoto Protocol now, and it does not have to come into force until at least a hundred years from now - a global freeze will come about regardless of whether or not industrialized countries put a cap on their greenhouse gas emissions," Abdusamatov said.
The cynical use Vladmir Putin's corrupt and anti-democratic regime is making of the Kyoto Protocols deserves its own post.