Carbon dioxide precedes temperature change during short-term pauses in multi-millennial palaeoclimate records

Abstract

In Antarctica, ice-core temperature has traditionally been regarded as a leading variable to carbon dioxide, CO⁠2 during the last 400,000years before present (B.P.). This finding is in contrast to most reports on global mean surface temperature and atmospheric CO⁠2 for the last 150years. However, previous techniques for establishing leading or lagging (LL) relations between paired global warming variables have required that the time series show constant frequency (stationarity). Herein, we show that on orbital and multi-millennial time scales, the Vostok Antarctic ice core displays 9 periods of 8.7kyr±5kyr during which CO⁠2 becomes a leading variable to temperature. Six of the 9 periods were associated with short-term pauses occurring during 4 major glaciation-deglaciation periods. We find that CO⁠2 also leads temperature during short pauses in the major cyclic pattern of the Greenland time series. In the latter series, there are also two contrasting cycle developments. In the first contrasting cycle developments, lasting from 103.5 to 79ka, there is an in-phase relation between CO⁠2 and temperature, with a slope of 0.75. In the second contrasting cycle developments, lasting from 61.5 to 43.5ka, there is an out-of-phase relation with a slope of −0.67. In addition, the latter shows a see-saw pattern between Arctic and Antarctic temperatures.