Den stora tråden om global uppvärmning/växthuseffekten

Figure 6a shows the computed and calibrated Jeffreys' priors for S for each main line of evidence, with Paleoclimate represented by LGM evidence combined with either mPWP or PETM evidence, and for all main lines of evidence combined, from S = 1 K upwards. Below that level, they start to become artefacted—as they do below ~ 1.5 K when using S20's data-variable assumptions—due to the paucity of samples for Process and Historical evidence. The likelihood and the probability are both almost zero below those levels, so the effect on inference for S is negligible.

The resulting estimates of long-term climate sensitivity are much lower and better constrained (median 2.16 °C, 17–83% range 1.75–2.7 °C, 5–95% range 1.55–3.2 °C) than in Sherwood et al. and in AR6 (central value 3 °C, very likely range 2.0–5.0 °C). This sensitivity to the assumptions employed implies that climate sensitivity remains difficult to ascertain, and that values between 1.5 °C and 2 °C are quite plausible.