Climateâ€™s always been changing and itâ€™s been changing rapidly at various times, and so something was making it change in the past,â€ he told us in an interview this past winter. â€œBefore there were enough people to make any difference at all, two million years ago, nobody was changing the climate, yet the climate was changing, okay?â€
â€œAll this argument is the temperature going up or not, itâ€™s absurd,â€ Bryson continues. â€œOf course itâ€™s going up. It has gone up since the early 1800s, before the Industrial Revolution, because weâ€™re coming out of the Little Ice Age, not because weâ€™re putting more carbon dioxide into the air.â€
Little Ice Age? Thatâ€™s what chased the Vikings out of Greenland after theyâ€™d farmed there for a few hundred years during the Mediaeval Warm Period, an earlier run of a few centuries when the planet was very likely warmer than it is now, without any help from industrial activity in making it that way. Whatâ€™s called â€œproxy evidenceâ€â€”assorted clues extrapolated from marine sediment cores, pollen specimens, and tree-ring dataâ€”helps reconstruct the climate in those times before instrumental temperature records existed.
We ask about that evidence, but Bryson says itâ€™s second-tier stuff. â€œDonâ€™t talk about proxies,â€ he says. â€œWe have written evidence, eyeball evidence. When Eric the Red went to Greenland, how did he get there? Itâ€™s all written down.â€
Bryson describes the navigational instructions provided for Norse mariners making their way from Europe to their settlements in Greenland. The place was named for a reason: The Norse farmed there from the 10th century to the 13th, a somewhat longer period than the United States has existed. But around 1200 the marinersâ€™ instructions changed in a big way. Ice became a major navigational reference. Today, old Viking farmsteads are covered by glaciers.
Bryson mentions the retreat of Alpine glaciers, common grist for current headlines. â€œWhat do they find when the ice sheets retreat, in the Alps?â€
We recall the two-year-old report saying a mature forest and agricultural water-management structures had been discovered emerging from the ice, seeing sunlight for the first time in thousands of years. Bryson interrupts excitedly.
â€œA silver mine! The guys had stacked up their tools because they were going to be back the next spring to mine more silver, only the snow never went,â€ he says. â€œThere used to be less ice than now. Itâ€™s just getting back to normal.â€
07 May 2007