Climate is only 1 of 9 planetary boundaries for the path to our rare opportunity.

Synopsis: First population, then nature, provide huge challenges to sustainability.

Most of us are not even aware that even without the impact of humans in this Anthropocene era, or that the planet is already dying.

While humans may be ultimately be provide the cure for the long-term environmental problems, without action, our technology and the population explosion could result in the premature death of the patient.

A population explosion creating a sustainability problem is not unique to humans, but with humans the overall picture is more complex.

The pattern often repeated in nature, where a species experiences a population explosion resulting in an unsustainable numbers and environmental damage, normally soon sees numbers return to normal and the environment recover. While some elements of this apply to our current situation, it is more complex, as evidenced by our population seeing long term modest growth even before the population explosion.

The technologies that enabled the population explosion coming ahead of the technologies to sustain that population have created some problems.

The environment faces both immediate, and longer-term problems:

• Immediate:
  1. CO₂ emissions and resultant climate change/extreme weather from the burning of fossil fuels.
  2. Other pollution.
  3. Many other species critical for the suffering environment loss, stresses and even potential extinction.
• Future:
  1. The progressive reduction in biomass from the reduction of CO2 levels required to avoid thermal runaway as solar radiation increases.
  2. Potential partial of full extinction threats from asteroids and meteors, volcanos and gamma-ray bursts.
  3. Inevitable natural total environmental collapse on this planet within as little as around 25 million years.

While, as explained by David Attenborough, all those immediate threats are due to us humans and are so pressing now due to our unprecedented population level, nature itself poses even greater threats in the longer term.

Emissions driving climate change may seem unrelated to population size but imagine the world with 1/4 of the current population. Assuming the same population mix, we would have 1/4 the emissions, providing for a far simpler transition away from fossil fuels.

Every immediate challenge can hopefully be solved even while at our current level of population, there are signs of overpopulation. Solving our environmental problems would be far simpler with a smaller population and would become far more difficult if population increases continue.

Many of our current challenges reflect that while we are currently managing to support numbers following the population explosion, we are currently doing so whilst effectively borrowing from future generations by doing so unsustainably. At some point, the damaged bill will need to be repaid.

Returning to sustainability is not our only problem, as the total biosphere size supported by the planet is in decline, and it could be said that the planet is dying. Time for life on Earth is also finite, and there is far less available than most people imagine, with less than 2% of time remaining for complex life on Earth.

Did we really think the Sun remains exactly as it is now for 5 million more years and then just suddenly explodes? Or that if the Sun is definitely going to explode, it must already be progressing towards that eventual explosion. It tuns out it could be as little as 25 million years along that marks and end for complex life like humans on Earth. Plus, it is not that 25 million years is perfection that comes to an overnight end either.

While even 1 million years is a long time for humanity, it is also almost certainly long enough to solve the problem of why cells age, triggering a second population crisis. Near elimination of childhood mortality requires a reduction in birthrate to around 2 children per couple, near elimination of old age mortality would require a much more drastic solution.

Unlike the current environmental challenges, the longer terms ones are not simply solved by humans stopping interfering with nature. In the long term, the only solution is to interfere with nature, and it is going to require far more developed technology than we possess today. Eventually, humanity will need to master the environment.

Sustainability in the traditional sense is not enough.

How long is needed to qualify as ‘sustainable’?

Most definitions of sustainable are vague.

Since nothing lasts forever, we cannot even properly define sustainability without deciding on a time frame.

This core problem with ‘sustainability’ is clear from the Wikipedia page:

Sustainability is a societal goal that broadly aims for humans to safely co-exist on planet Earth over a long time.

Sustainability: Wikipedia

Many people initially assume sustainability should mean indefinitely, but as we also understand that even the Sun would last forever, then there are some limitations. But what limitations define “a long time”?

Just what constitutes ‘a long time’?

To a five-year-old, an hour is a long time. As we get older, the perception of what is ‘a long time’ stretches with our time horizons.

A ‘long time’ is relative. Dinosaurs ‘co-existed’ on planet Earth for a ‘long time’. So long that there was almost 130 million years between the time of earlier dinosaurs such as Dilophosaurus that lived 190 million years ago, and the time when Tyrannosaurus Rex roamed the planet 66 million years ago. This makes T-Rex almost twice as close to our time, as T-Rex was to the time of earlier dinosaurs.

On that basis, a ‘long time’ could be as long as over 100 million years.

However, the reality is, life on Earth is on the decline even without humans damaging the environment, and while there may be some life left 100 million years even nature will not sustain complex for 100 million years,

All thing considered, a ‘long time’ could be for ‘as long as Earth will naturally support human life’.

Does sustainability stretch to humans preserving life beyond its natural end?

Considering that nature will only support the existence of humans for as little as 25 million years, and for that entire time support for complex life would be decreasing, if humans have not prematurely orchestrated their own demise and continue to advance technology, self-preservation alone would require interfering with nature and finding a way to extend support for complex life on Earth.

Perhaps ‘sustainability’ should be extended to ensuring the life of Earth is sustained for as long as possible?

The 9 Planetary boundaries.

6 of 9 boundaries crossed as of 2023.

As of 2023, 6 of the 9 “planetary boundaries” have been crossed, with the implications that “Conditions on Earth may be moving outside the ‘safe operating space’ for humanity, according to dozens of scientists“.

What are the planetary boundaries?

The nine “planetary boundaries” represent components of the global environment that regulate that stability and livability of the planet for people. The degree of breaching of the safe boundary levels is caused by human-driven activities impacting the components.

Phys.org, Sept 13 2023: Six of nine planetary boundaries now exceeded

Or, from Wikipedia:

The 2009 study identified nine planetary boundaries and, drawing on current scientific understanding, the researchers proposed quantifications for seven of them. These are:

1. climate change (CO₂ concentration in the atmosphere < 350 ppm and/or a maximum change of +1 W/m² in radiative forcing);
2. ocean acidification (mean surface seawater saturation state with respect to aragonite ≥ 80% of pre-industrial levels);
3. stratospheric ozone depletion (less than 5% reduction in total atmospheric O₃ from a pre-industrial level of 290 Dobson Units);
4. biogeochemical flows in the nitrogen (N) cycle (limit industrial and agricultural fixation of N₂ to 35 Tg N/yr) and phosphorus (P) cycle (annual P inflow to oceans not to exceed 10 times the natural background weathering of P);
5. global freshwater use (< 4000 km³/yr of consumptive use of runoff resources);
6. land system change (< 15% of the ice-free land surface under cropland);
7. the erosion of biosphere integrity (an annual rate of loss of biological diversity of < 10 extinctions per million species).
8. chemical pollution (introduction of novel entities in the environment).

For one process in the planetary boundaries framework, the scientists have not specified a global boundary quantification:

9. atmospheric aerosol loading;

The quantification of individual planetary boundaries is based on the observed dynamics of the interacting Earth system processes included in the framework. The control variables were chosen because together they provide an effective way to track the human-caused shift away from Holocene conditions.

Planetary boundaries

Conclusion.

We can’t really even properly define ‘sustainable‘ without a framework that provides a bigger picture.

Consider the mission:

One Finite Planet is a societal goal that broadly aims for humans to safely co-exist on planet Earth whilst all working towards overcoming the limits of existing on only one finite planet.

Humanity needs goals and this is more a mission statement than tangible goals to pursue, but if the mission could be adopted by enough people, then there can be collaborative work on the goals.

Updates.

• *2023 April 7 th: Synopsis.
• *2022 October 2: Added mission.
• 2021 December 12: First version.

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