Making the job harder still, baffling anomalies turned up.The carbon-14 dates published by different researchers could not be reconciled, leading to confusion and prolonged controversy.One application was a timetable of climate changes for tens of thousands of years back.Many of the traditional chronologies turned out to be far less accurate than scientists had believed a bitter blow for some who had devoted decades of their lives to the work.For example, Hans Suess relied on a variety of helpers to collect fragments of century-old trees from various corners of North America.He was looking for the carbon that human industry had been emitting by burning fossil fuels, in which all the carbon-14 had long since decayed away.The best way to transfer the exacting techniques was in the heads of the scientists themselves, as they moved to a new job.Tricks also spread through visits between laboratories and at meetings, and sometimes even through publications.
The results were then compared with traditional time sequences derived from glacial deposits, cores of clay from the seabed, and so forth.
De Vries thought the variation might be explained by something connected with climate, such as episodes of turnover of ocean waters.(7) Another possible explanation was that, contrary to what everyone assumed, carbon-14 was not created in the atmosphere at a uniform rate.
Some speculated that such irregularities might be caused by variations in the Earth's magnetic field.
A stronger field would tend to shield the planet from particles from the Sun, diverting them before they could reach the atmosphere to create carbon-14.
and "not very attractive."(8) However, solar specialists knew that the number of particles shot out by the Sun varies with the eleven-year cycle of sunspots.