Appendix 2—table 1. Summary of simulated vs. climate envelope-based treeline advance.
Climate envelope solely based on July temperatures (following MacDonald et al., 2007). Values in bold reach the shoreline, but note that because of technical reasons the step sizes of the climate are in 10-km steps. Values are the result of three simulation repeats, and the standard deviation is stated next to the mean value.
| Transect | Scenario | Maximum potential expansion based on climate and year | Simulated maximum expansion and year | Treeline migration rate 2000– | Treeline migration rate 2000– |
|---|---|---|---|---|---|
| Taimyr | RCP 2.6* | 210 km 2090 | 192.2 ± 18.5 km 2733 ± 162 | 0.8 ± 0.7 | 1.5 ± 0.1 |
| RCP 2.6*c | 210 km 2090 | 135.3 ± 1.4 km 2357 ± 58 | 3.4 ± 2.9 | 1.9 ± 0 | |
| RCP 2.6 | 320 km 2090 | 344.8 ± 2.9 km 2730 ± 87 | 11.5 ± 2.3 | 9 ± 0 | |
| RCP 2.6c | 320 km 2090 | 331.3 ± 1.4 km 2283 ± 29 | 8.6 ± 1.2 | 8.6 ± 0.1 | |
| RCP 4.5 | 410 km 2297 | 544.5 ± 0 km 2383 ± 6 | 23.4 ± 0.2 | 10.6 ± 0.1 | |
| RCP 4.5c | 400 km 2221 | 405.3 ± 3.8 km 2567 ± 231 | 24.7 ± 0.2 | 11.2 ± 0.1 | |
| RCP 8.5 | 560 km 2082 | 544.5 ± 0 km 2160 ± 0 | 29.1 ± 0.5 | 16.1 ± 0 | |
| RCP 8.5c | 560 km 2082 | 544.5 ± 0 km 2140 ± 0 | 28.4 ± 0.4 | 16.2 ± 0 | |
| Buor Khaya | RCP 2.6* | 130 km 2040 | 94.5 ± 0.9 km 2307 ± 75 | 0.1 ± 0.2 | 0.2 ± 0 |
| RCP 2.6*c | 130 km 2040 | 91 ± 0.9 km 2497 ± 318 | 0 ± 0 | 0 ± 0 | |
| RCP 2.6 | 130 km 2020 | 120.2 ± 1.4 km 2247 ± 12 | 1 ± 0.3 | 1.1 ± 0 | |
| RCP 2.6c | 130 km 2020 | 122.3 ± 0.3 km 2633 ± 92 | 0.9 ± 0.6 | 1.2 ± 0.2 | |
| RCP 4.5 | 140 km 2133 | 124.5 ± 0 km 2303±6 | 0.6 ± 0.5 | 1.3 ± 0.1 | |
| RCP 4.5c | 140 km 2133 | 124.5 ± 0 km 2287 ± 12 | 0.2 ± 0.1 | 1.2 ± 0.1 | |
| RCP 8.5 | 140 km 2038 | 124.5 ± 0 km 2120 ± 0 | 3.2 ± 0 | 1.2 ± 0 | |
| RCP 8.5c | 140 km 2038 | 124.5 ± 0 km 2123 ± 12 | 3 ± 0.3 | 1.1 ± 0 | |
| Kolyma | RCP 2.6* | 130 km 2012 | 120.8 ± 0.3 km 2330 ± 0 | 1.2 ± 0.1 | 0.7 ± 0 |
| RCP 2.6*c | 130 km 2012 | 119 ± 0.9 km 2217 ± 12 | 1.1 ± 0.2 | 0.7 ± 0 | |
| RCP 2.6 | 150 km 2094 | 134.3 ± 0.3 km 2230 ± 0 | 2.1 ± 0.1 | 1.2 ± 0 | |
| RCP 2.6c | 150 km 2094 | 113.5 ± 17.3 km 2103 ± 92 | 1.3 ± 0.6 | 1 ± 0.1 | |
| RCP 4.5 | 150 km 2284 | 134.5 ± 0 km 2257 ± 12 | 2 ± 0.1 | 1.2 ± 0 | |
| RCP 4.5c | 140 km 2121 | 134.5 ± 0 km 2307 ± 6 | 1.6 ± 0.5 | 1.2 ± 0 | |
| RCP 8.5 | 150 km 2072 | 134.5 ± 0 km 2143 ± 6 | 2.2 ± 0.2 | 1.2 ± 0 | |
| RCP 8.5c | 150 km 2072 | 134.5 ± 0 km 2140 ± 0 | 2.2 ± 0.1 | 1.2 ± 0 | |
| Chukotka | RCP 2.6* | 300 km 2047 | 285.2 ± 8.4 km 2173 ± 29 | 25.1 ± 0.1 | 8.8 ± 0.1 |
| RCP 2.6*c | 300 km 2047 | 285.7 ± 3.2 km 2203 ± 29 | 25.3 ± 0.2 | 9.2 ± 0.1 | |
| RCP 2.6 | 350 km 2047 | 363.5 ± 0 km 2423 ± 6 | 30.8 ± 1 | 11.3 ± 0.2 | |
| RCP 2.6c | 350 km 2047 | 358.8 ± 6.4 km 2290 ± 87 | 30.9 ± 0.2 | 11.3 ± 0.2 | |
| RCP 4.5 | 380 km 2144 | 604.5 ± 0 km 2747 ± 29 | 27.2 ± 1.2 | 12 ± 0 | |
| RCP 4.5c | 380 km 2144 | 377 ± 0 km 2297 ± 6 | 28 ± 0.2 | 11.9 ± 0.1 | |
| RCP 8.5 | 610 km 2107 | 604.5 ± 0 km 2160 ± 0 | 29.1 ± 0.3 | 19.6 ± 0 | |
| RCP 8.5c | 610 km 2107 | 604.5 ± 0 km 2150 ± 0 | 29.2 ± 0.1 | 19.7 ± 0 |