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France and the nine planetary boundaries
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2023 Revision of the nine planetary boundaries framework

In September 2023, the Stockholm Resilience Centre published an update of the conceptual framework of the nine planetary boundaries proposed in 2009 (Rockström et al.) and revised in 2015 (Steffen et al.). For the first time, the nine planetary boundaries are quantified (Richardson et al.38, 2023). New control variables are assigned to four boundaries (biosphere integrity/functional diversity, freshwater/blue water cycle, aerosols in the atmosphere, new entities), revealing or confirming that they have been exceeded (Diagram 2). The level of exceedance increases for all boundaries previously considered exceeded (Diagram 1).

Scientists have established that six of the nine planetary boundaries have now been exceeded: climate change, biosphere integrity, disruption of the biogeochemical cycles of nitrogen and phosphorus, land use change, freshwater use, and the introduction of new entities. This means that the planet is now well beyond safe operating space for humanity.

Diagram 1: Planetary boundaries of the 2015 framework updated to 2022 (left)
Diagram 2: Planetary boundaries of the 2023 framework (right)

Sources Diagram 1: Steffen et al., 2015; Personn et al., 2021 ; Wang-Erlandsson etal., 2022
Source Diagram 2: Richardson et al., 2023

The following table presents the nine planetary boundaries, with their assigned control variables, pre-industrial reference values, thresholds not to be exceeded and current values from the latest Stockholm Resilience Centre publication of September 2023. These are juxtaposed with the previously known variables and values used in the present publication (early 2023 version).

38 Richardson K. et al., 2023. Earth beyond six of nine planetary boundaries. Sciences Advances. Vol. 9, Issue 37.

Earth system
processes

Control variable

Reference value, pre-industrial era (Holocene)

Zone of increasing risk -
Planetary boundary

low threshold - high threshold

Current value
of the control variable

Version
early 2023,
used for
this publication

Version
of September 13, 2023

Known at the beginning of 2023 and used for this publication

Published
on September 13, 2023

Climate change

Atmospheric CO2 concentration in parts per million (ppm)

280 ppmCO₂

350 to 450 ppmCO₂

idem

425 ppmCO₂

417 ppmCO₂

Increase in radiative forcing in watts per square metre (W/m²) compared with the pre-industrial era

0W/m² for

+ 1.0 to + 1.5W/m²(in W/m²)

idem

2.72W/m²+ 2.72 W/m

2.91W/m²+ 2.91 W/m

Biosphere integrity

Genetic diversity: extinction rate of 1million species per year (E/MEA)

1 E/MEA

10 to 100 E/MEA

idem

> 100 E/MEA

idem

Functional diversity: Biodiversity intactness index (BII) compared to pre-industrial times, in%.

100 %

90 to 30% for biomes, large regional areas, major marine ecosystems or large functional groups

Discontinued variable

77 %

Discontinued variable

Functional diversity: energy available to ecosystems through the share of the biosphere's annual net primary production (NPP expressed in giga tonnes of carbon per year - Gtde C/yr) taken up by man (HANPP expressed as a% of pre-industrial NPP).

1.9% of the biosphere's net primary production (estimated at 55.9Gtof C/year) is extracted by humans

Not specified as new variable proposed with framework revision in September 2023

10 to 20% HANPP (10% to 20% of the biosphere's net primary production is taken by man)

30% HANPP (16.8Gtde C/year withdrawn in 2020 / 55.9Gtde C/year produced on average before the pre-industrial era)

Stratospheric ozone

Atmospheric ozone concentration measured in Dobson units (DU)

290 DU

275 DU (276 DU corresponds to a 5% reduction in the pre-industrial value assessed by latitude)

276 to 261 DU

285 DU

284.6 DU

Ocean acidification

Aragonite saturation state of global surface ocean (% of pre-industrial value) - (Ωarag)

3.44Ωarag

80% to 70% of the aragonite saturation state of global surface ocean in the pre-industrial era (i.e. 2.75 to 2.4Ωarag)

2.75Ωarag

2.9Ωarag (84%)

2.8Ωarag

Nitrogen and phosphorus cycles

Global scale: phosphate emissions from freshwater systems to the oceans, in millions of tonnes (Mt) per year

0 Mt/year

11 to 100Mt/year

idem

22Mt/year

22.6Mt/year

Regional scale: quantity of phosphate in fertilizers applied to agricultural soils, in Mt per year

6.2 to 11.2Mt/year

idem

14.2Mt/year

17.5Mt/year

Quantity of reactive nitrogen released by human activities in Mt per year, worldwide

0 Mt/year

62 to 82Mt/year

idem

150Mt/year

190Mt/year

Land-system change

Global scale: ratio of current forest area to "original" forest area(before 1700) Biome: ratio of current biome forest area to "original" biome forest area(before1700)

100 %

Global: 75 to 54% (weighted average of the three individual biome boundaries) Biomes:
Tropical 85 to 60%; Temperate 50 to 30%; Boreal 85 to 60%.

idem

Global: 62% Temperate: 50% Tropical and boreal: 68

Global: 60%
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%).

Use of freshwater

Blue Water - Global: total volume of freshwater consumed, withdrawn from renewable surface and groundwater resources. Blue Water - Local: a maximum freshwater abstraction threshold is proposed on a watershed scale and according to the seasonal hydrological regime.

Global: 4,000 to 6,000 km3 /year
Local: 25% in low-water period (25-55%)
40% in intermediate period (40-70%)
55% in high-water period (55-85%)

Variable
discontinued

2,600 km3 of fresh water consumed per year

Discontinued variable

The latest estimate of global freshwater consumption is 1,700 km3 .

Blue water: human-induced flow disturbances
Upper limit ( 95th percentile) of the world's land surface, with deviations greater than in the pre-industrial period.

9.4% (pre-industrial average)

Not specified as new variable proposed with framework revision in September 2023

10.2% to 50% (provisional upper threshold value)

18,2%

Green water: % of ice-free land area in which soil moisture in the root zone deviates from the natural variability observed over thelast11,000years.

9.8% (pre-industrial average)

10% (no high threshold specified)

11.1% to 50% (provisional upper threshold value)

18% (provisional value)

15,8%

Aerosol

Aerosol optical depth (AOD)

No global threshold defined, in the absence of sufficient knowledgePilotcase: Southeast Asia zone: 0.25 to 0.5 AOD

Variable
discontinued

Pilot case: Southeast Asia
 0.3 AOD

Variable
discontinued

Interhemispheric difference in aerosol optical thickness (AOD)

0,03

Not specified as new variable proposed withframework revision in September 2023

0,1 à 0,25

0,076

Novel entities

Percentage of synthetic chemicals released into the environment without adequate safety testing

0

Not specified

0 to ?
(high threshold not defined)

Exceeded