Anomalous 11-Year Delta-14C Cycle at High Latitudes?

Abstract

We find no evidence for an anomalously intense 11-yr cycle in Delta-14C at high latitudes during the period, AD 1870–1885, as reported by Fan et al. (1983, 1986). However, there does appear to be a regional effect within the MacKenzie River region (67 degrees N, 130 degrees W), with atmospheric 14C depressed by 2.6 +/0.9 (mean of sigma) % relative to the Olympic Peninsula. Such an effect would require only 5% of CO2 in the air mass to have been derived from 5% 14C-depleted soil gas CO2. This small but apparently significant regional effect could be caused by accumulation of CO2 within the frozen earth followed by outgassing during the spring thaw. The short growing season would enhance the effect by allowing insufficient time for global atmospheric equilibration.