|
Climate change
|
Atmospheric CO2 concentration (ppm CO2) |
350 ppm CO2
|
280 ppm CO2
|
450 ppm CO2
|
417 ppm CO2 (41) |
| Total anthropogenic radiative forcing at top-of-atmosphere (W m−2) |
+1.0 W m−2
|
0 W m−2
|
+1.5 W m−2
|
+2.91 W m−2 (41) |
|
Change in biosphere integrity
|
Genetic diversity: E/MSY |
<10 E/MSY but with an aspirational goal of ca. 1 E/MSY (assumed background rate of extinction loss) |
1 E/MSY |
100 E/MSY |
>100 E/MSY (24–26) |
| Functional integrity: measured as energy available to ecosystems (NPP) (% HANPP) |
HANPP (in billion tonnes of C year−1) <10% of preindustrial Holocene NPP, i.e., >90% remaining for supporting biosphere function |
1.9% (2σ variability of preindustrial Holocene century-mean NPP) |
20% HANPP |
30% HANPP (see the Supplementary Materials) |
|
Stratospheric ozone depletion
|
Stratospheric O3 concentration, (global average) (DU) |
<5% reduction from preindustrial level assessed by latitude (~276 DU) |
290 DU |
261 DU |
284.6 DU (96) |
|
Ocean acidification
|
Carbonate ion concentration, average global surface ocean saturation state with respect to aragonite (Ωarag) |
≥80% Ωarag of mean preindustrial aragonite saturation state of surface ocean, including natural diel and seasonal variability |
3.44 Ωarag
|
2.75 Ωarag
|
2.8 Ωarag (71) |
|
Biogeochemical flows: P and N cycles
|
Phosphate global: P flow from freshwater systems into the ocean; regional: P flow from fertilizers to erodible soils (Tg of P year−1) |
Phosphate global: 11 Tg of P year−1; regional: 6.2 Tg of P year−1 mined and applied to erodible (agricultural) soils. Boundary is a global average, but regional distribution is critical for impacts. |
0 Tg of P year−1
|
Global: 100 Tg of P year−1; regional: 11.2 Tg of P year−1
|
Global: 22.6 Tg of P year−1 (75); regional: 17.5 Tg of P year−1 (76) |
| Nitrogen global: industrial and intentional fixation of N (Tg of N year−1) |
Nitrogen global: 62 Tg of N year−1. Boundary is a global average. Anthropogenic biological N fixation on agriculture areas highly uncertain but estimates in range of ~30 to 70 Tg of N year−1. Boundary acts as a global “valve” limiting introduction of new reactive N to Earth system, but regional distribution of fertilizer N is critical for impacts. |
0 Tg of N year−1
|
82 Tg of N year−1
|
190 Tg of N year−1 (84) |
|
Land system change
|
Global: area of forested land as the percentage of original forest cover; biome: area of forested land as the percentage of potential forest (% area remaining) |
Global: 75% values are a weighted average of the three individual biome boundaries; biomes: tropical, 85%; temperate, 50%; boreal: 85% |
100% |
Global: 54%; biomes: tropical, 60%; temperate, 30%; boreal: 60% |
Global: 60% [(72, 97) and see the Supplementary Materials]; tropical: Americas, 83.9%; Africa, 54.3%; Asia, 37.5%; temperate: Americas, 51.2%; Europe, 34.2%; Asia, 37.9%; boreal: Americas, 56.6%; Eurasia: 70.3% |
|
Freshwater change
|
Blue water: human induced disturbance of blue water flow |
Upper limit (95th percentile) of global land area with deviations greater than during preindustrial, Blue water: 10.2% |
9.4% (median of preindustrial conditions) |
50% (provisional) |
18.2% (46) |
| Green water: human induced disturbance of water available to plants (% land area with deviations from preindustrial variability) |
Green water: 11.1% |
9.8% (median of preindustrial conditions) |
50% (provisional) |
15.8% (46) |
|
Atmospheric aerosol loading
|
Interhemispheric difference in AOD |
0.1 (mean annual interhemispheric difference) |
0.03 |
0.25 |
0.076 (55, 57, 68) |
|
Novel entities
|
Percentage of synthetic chemicals released to the environment without adequate safety testing |
0 |
0 |
NA |
Transgressed |
