Sunday, June 22, 2008

Historical climate change

An upcoming publication documents climate change in Finland over the past 7500 years on the basis of a continuous tree-ring chronology. What it shows is that past climates were indeed warmer than today's and that climate is constantly changing:
  • Timonen et al. write "The warmest and coldest reconstructed 250-year periods occurred AD 931-1180 and AD 1601-1850. These periods overlap with the Medieval Warm Period (MWP) and the Little Ice Age (LIA). The coldest and warmest of all reconstructed 100-year periods occurred AD 1587-1686 and AD 1895-1994, respectively".
  • ...the warmest period of the past 1,300 years occurred during AD 931-1180.
  • ...summer temperatures in Finland peaked in 1950 and have been cooling ever since.
Some see this persistent presentation of contrary data as dissent. Some call it denial. To me, it represents proper scientific method: go with what data you have, until it can be replaced by better information that you collect and assess because you acknowledge the limitations of the data you have in hand. But then, of course, good science to me does not involve actively promoting hysteria that fits your ideology but not the facts: that's politics, bad politics, but still politics and not science.