Millennial-Scale Rhythms in Peatlands in the Western Interior of Canada and in the Global Carbon Cycle

Abstract

A natural ∼1450-yr global Holocene climate periodicity underlies a portion of the present global warming trend. Calibrated basal radiocarbon dates from 71 paludified peatlands across the western interior of Canada demonstrate that this periodicity regulated western Canadian peatland initiation. Peatlands, the largest terrestrial carbon pool, and their carbon-budgets are sensitive to hydrological fluctuations. The global atmospheric carbon-budget experienced corresponding fluctuations, as recorded in the Holocene atmospheric CO2 record from Taylor Dome, Antarctica. While the climate changes following this ∼1450-yr periodicity were sufficient to affect the global carbon-budget, the resultant atmospheric CO2 fluctuations did not cause a runaway climate–CO2 feedback loop. This demonstrates that global carbon-budgets are sensitive to small climatic fluctuations; thus international agreements on greenhouse gasses need to take into account the natural carbon-budget imbalance of regions with large climatically sensitive carbon pools.