Fig. 4
From: Recent summer warming in northwestern Canada exceeds the Holocene thermal maximum
Precipitation and pore ice isotope climatology. a Monthly δDprecip (see Supplementary Fig. 4 for δ18O) and b monthly dexcess calculated from Mayo GNIP (Global Network of Isotopes in Precipitation) data (grey circles and 1σ error bars; excludes suspected evaporation-enriched data points shown in Fig. 3a); Mayo mean annual δDprecip and dexcess (dashed black lines), mean DHP174-13 (Dempster Highway Peatland, near 174 km marker) top-of-permafrost (58–60 cm) pore ice δD and dexcess (solid red lines) and estimated initial pore water δD and dexcess (dashed red lines) are indicated; c comparison of δDpore ice (top-of-permafrost)-based temperature estimate (red line; red band = ± 1σ uncertainty; Methods) and mean monthly (black circles) and mean annual (black dashed line) temperatures at the Ogilvie River Environment Canada station (1971–2007 period of record; Supplementary Note 3); d mean total monthly snowfall (white bars; in snow-water equivalent) and rain (black bars) at Ogilvie River. The shaded area represents the average thaw season (i.e. period when mean daily air temperatures are above freezing)
