This article was an interesting read.

Climate stability has never been a feature of planet Earth. The only constant about climate is change; it changes continually and, at times, quite rapidly.

My interest in the current climate-change debate was triggered in 1998, when I was funded by a Natural Sciences and Engineering Research Council strategic project grant to determine if there were regular cycles in West Coast fish productivity.

My research team began to collect and analyze core samples from the bottom of deep Western Canadian fjords... ...As a consequence, the floors of these basins are mostly lifeless and sediment layers build up year after year, undisturbed over millennia.

Using various coring technologies, we have been able to collect more than 5,000 years' worth of mud in these basins

Using computers to conduct what is referred to as a "time series analysis" on the colouration and thickness of the annual layers, we have discovered repeated cycles in marine productivity in this, a region larger than Europe. Specifically, we find a very strong and consistent 11-year cycle throughout the whole record in the sediments and diatom remains. This correlates closely to the well-known 11-year "Schwabe" sunspot cycle, during which the output of the sun varies by about 0.1%. Sunspots, violent storms on the surface of the sun, have the effect of increasing solar output, so, by counting the spots visible on the surface of our star, we have an indirect measure of its varying brightness. Such records have been kept for many centuries and match very well with the changes in marine productivity we are observing.

In the sediment, diatom and fish-scale records, we also see longer period cycles, all correlating closely with other well-known regular solar variations. In particular, we see marine productivity cycles that match well with the sun's 75-90-year "Gleissberg Cycle," the 200-500-year "Suess Cycle" and the 1,100-1,500-year "Bond Cycle."

Posted by Michael at June 20, 2007 08:38 PM