The nice thing about the term "Climate Change" is that it covers all possibilities. The Daily Mail reports:
Based on readings from more than 30,000 measuring stations, the data was issued last week without fanfare by the Met Office and the University of East Anglia Climatic Research Unit. It confirms that the rising trend in world temperatures ended in 1997. ...
Meanwhile, leading climate scientists yesterday told The Mail on Sunday that, after emitting unusually high levels of energy throughout the 20th Century, the sun is now heading towards a ‘grand minimum’ in its output, threatening cold summers, bitter winters and a shortening of the season available for growing food. ...
Analysis by experts at NASA and the University of Arizona – derived from magnetic-field measurements 120,000 miles beneath the sun’s surface – suggest that Cycle 25, whose peak is due in 2022, will be a great deal weaker still.
What this represents is an empirical test of the hypothesis that solar activity affect the earth's climate more than Greenhouse Gases. Watts Up With That describes how the estimates of the sun's activity are predicted.
What drives Sol, in turn, is the subject of a theory called the Great Conveyor Belt, "a massive circulating current of fire (hot plasma) within the Sun. It has two branches, north and south, each taking about 40 years to perform one complete circuit. Researchers believe the turning of the belt controls the sunspot cycle."
According to NASA scientist John Casey, the drop in the solar activity will lead in turn to cold weather. Five years ago, Casey predicted there would be rising temperatures because models at the time predicted a heightened solar activity. But now that new data suggests a decline, his theory compels a prediction of global cooling.
So what's the truth? The answer is that we shall see. The coming years will provide a data point on whether or not there is a likelihood that terrestrial climate is related to what goes on in the sun. But it is just a data point. Casey argues that the pattern has a 90% fit with past data. So the question is whether the correlation will be borne out in the future.
"We today confirm the recent announcement by NASA that there are historic and important changes taking place on the sun's surface. This will have only one outcome - a new climate change is coming that will bring an extended period of deep cold to the planet. This is not however a unique event for the planet although it is critically important news to this and the next generations. It is but the normal sequence of alternating climate changes that has been going on for thousands of years. Further according to our research, this series of solar cycles are so predictable that they can be used to roughly forecast the next series of climate changes many decades in advance. I have verified the accuracy of these cycles' behavior over the last 1,100 years relative to temperatures on Earth, to well over 90%."
But science ought not to consist of a rush to judgment from one theory to the other. The great danger of presenting something like AGW as "settled science" is that it opens the whole position to being undermined by new empirical evidence. If there turns out to be no correlation between the solar cycles and climate, the AGW crowd will be trumpeting the fact from every media hilltop. But if -- as seems not unlikely -- the sun's activity does drive terrestrial climate to a large extent, what then?
What of those billions of dollars invested in carbon trading? In zero-carbon houses and building codes? In the excoriation of climate criminals? Can people sue to get their money and reputations back? Probably not. After all, the Climate Change advocates meant well.