Fig. 4 | Nature Communications

Fig. 4

From: Deep-water circulation changes lead North Atlantic climate during deglaciation

Fig. 4

Detailed view of synchronized CO2, climate and ocean circulation records during the Younger Dryas stadial. a CO2 concentration from WDC ice cores. b Greenland temperature reconstruction109 (average of NEEM, GISP2 and NGRIP ice cores). c Nordic Sea deep water formation rate based on B-P ages from core MD99-2284 (this study). Triangles indicate the location of individual planktic (blue) and (benthic) 14C measurements. d Atmospheric radiocarbon content (Δ14C) corrected for changes in natural 14C production27. The record was high-pass filtered (cut-off frequency 1/200 years) to facilitate comparison with long-term overturning strength variations (c). All the records were generated by MCMC using the same random walk model approach used to estimate 14C ventilation, but the model was fitted directly to the observations. Grey envelopes reflect the 68% credible intervals (1σ) associated with both analytical and chronological uncertainty in the raw data. Coloured segments represent the 68% confidence intervals of the fitted piecewise linear regression functions accounting for both analytical and chronological uncertainties. The regression models were estimated using a modified version of an algorithm for breakpoint analysis100. Note that only the sharp decline in Δ14C during the second half of GS-1 (YD) can be attributed to a resumption of NADW formation27, whereas the preceding minor decline is likely a dynamical response in the Southern Ocean associated with venting of 14C-depleted carbon110. e 95% confidence intervals of the timing and duration of the transitions (Supplementary Table 1). Inset black lines show the 2σ uncertainty of the estimated start and end of each transition. Greenland stratigraphic events relative to the IntCal13 timescale are displayed at the top (GS: Greenland Stadial; GI: Greenland Interstadial; YD: Younger Dryas Stadial; BA: Bølling-Allerød Interstadial)