We are all aware of climate change and the devastating impacts we are now seeing due to global warming. However, for most of us, this is all theorectical and we have no idea of where we are in relation to when climate change will be irreversible.

About a decade ago at team of international ,interdisciplinary scientists headed by Johan Rockström – founding director of Sweden’s Stockholm Resilience Centre, – identified areas where human activities will have major climate impacts. They identified these areas as Planetary Boundaries. We can then identify the boundaries for a “safe operating space for humanity” on earth. This also informs us about what changes we can force on these boundaries before we trigger rapid, catastrophic environmental harm. It also informs us of when we need to stop and make changes in how we interact with the planet.

How are we going in our efforts to deal with climate change?

Unfortunately, as of 2015 we had already passed 4 of the 9 boundaries which puts us on a very precarious footing as we head into an uncertain future. The Paris Agreement was set up in 2015 and 175 countries agreed to participate and to work towards lowering greenhouse gas emissions. The ultimate goal was to reach zero emissions by 2050.

Sadly, many countries, and Australia is one of these, are failing to take strong actions and not meeting the agreed limits. Australia’s government is continuing to rely on fossil fuels and uses the fact that other countries are higher emitters to justify their lack of appropriate action. The fact that the Paris Agreement set the net zero target to 2050, may have reduced the sense of urgency and given countries a false sense of security. There certainly seems to be a “burn now and pay later” mentality.

The earth is heating up faster than expected and we have to act now to enable us to have a sustainable future.

At this point, the need is urgent to dramatically reduce carbon emissions, but we also have to find ways to draw down the carbon that is already in the atmosphere. While we are all pondering this, carbon emissions are continuing to be pumped into the atmosphere.

What are the Planetary Boundaries?

1. Atmospheric Aerosol Loading – Particle Pollution

This is not yet quantified, though aerosol particles that enter our atmosphere can be very damaging to human health.  The boundary was proposed primarily because of the influence of aerosols on Earth’s climate system. Through their interaction with water vapour, aerosols play a critically important role in our water cycles, affecting cloud formation and global / regional patterns of atmospheric circulation, such as the monsoon systems in tropical regions. They also have a direct effect on climate, by changing how much solar radiation is reflected or absorbed in the atmosphere.

2. Biochemical Flows – Nitrogen and Phosphorus

Nitrogen and phosphorus are both essential elements for plant growth, so fertilizer production and application is the main concern.  Human activities now convert more atmospheric nitrogen into reactive forms than all of the Earth’s terrestrial processes combined. Much of this new reactive nitrogen is emitted to the atmosphere in various forms rather than taken up by crops. When it is rained out, it pollutes waterways and coastal zones, a threshold we are already crossing.

3. Land System Change

Forests, grasslands, wetlands and other vegetation types are primarily being converted to agricultural land by humans. This activity is undoubtedly behind the serious reductions in biodiversity, and it impacts on water flows and on the biogeochemical cycling of carbon, nitrogen and phosphorus and other important elements. Scientists say that a boundary for human changes to land systems needs to reflect not just the absolute quantity of land, but also its function, quality and spatial distribution.

4. Freshwater Use

The consequences of human modification of water bodies include both global-scale river flow changes and shifts in vapour flows arising from land use change. These shifts in the hydrological system can be abrupt and irreversible. Water is becoming increasingly scarce – by 2050 about half a billion people are likely to be subject to water-stress.

5. Ocean  Acidification

25% of the CO2 that humans emit into the atmosphere is ultimately dissolved in the oceans. Here it forms carbonic acid, altering ocean chemistry and decreasing the pH of the surface water.  Beyond a threshold concentration, this rising acidity makes it hard for organisms such as corals and some shellfish and plankton species to grow and survive, and losing various species would greatly impact on marine ecosystems.  CO2 concentration is the underlying controlling variable for both the climate and the ocean acidification boundaries.

6. Climate Change

We have sadly already passed this planetary boundary due to the levels of CO2 in the atmosphere. We are already losing summer polar sea-ice, and weakening carbon sinks, so really the question now is: how long we can remain over this boundary before large, irreversible changes become unavoidable?

7. Novel Entities – Chemical Pollution

Emissions of toxic and long-lived substances such as synthetic organic pollutants, heavy metal compounds and radioactive materials represent some of the key human-driven changes to the planetary environment. These compounds can have potentially irreversible effects on living organisms and on the physical environment.  At present, we are unable to quantify a single chemical pollution boundary, although the risk of crossing Earth system thresholds is considered sufficiently well-defined for it to be included in the list.

8. Biosphere Integrity – Biodiversity Loss

The demand for food, water and resources are the main drivers for change. The current high rates of ecosystem damage and extinction can be slowed by efforts to protect the integrity of living systems (the biosphere), enhancing habitat, and improving connectivity between ecosystems while maintaining the high agricultural productivity that humanity needs.

9. Ozone Depletion

The stratospheric ozone layer in the atmosphere filters out ultraviolet (UV) radiation from the sun. If this layer decreases, increasing amounts of UV radiation will reach ground level. This can cause a higher incidence of skin cancer in humans as well as damage to terrestrial and marine biological systems. Fortunately, because of the actions taken as a result of the Montreal Protocol, we appear to be on the path that will allow us to stay within this boundary.

The Montreal Protocol on Substances that Deplete the Ozone Layer is an international agreement made in 1987. It was designed to stop the production and import of ozone depleting substances and reduce their concentration in the atmosphere to help protect the earth’s ozone layer.

This information sourced from the Stockholm Resilience Centre Posted by Claire Edwards 29 July 2021 from the website Planetary.

Where we are currently

What will the future hold?

What now?

“The time has come to voice our fears and be honest with wider society. Current net zero policies will not keep warming to within 1.5°C because they were never intended to. They were and still are driven by a need to protect business as usual, not the climate. If we want to keep people safe then large and sustained cuts to carbon emissions need to happen now. That is the very simple acid test that must be applied to all climate policies. The time for wishful thinking is over.”

Excerpt from the article – Climate scientists: concept of net zero is a dangerous trap

Published April 22, 2021 2.25pm AEST  The Conversation

Individuals can take action!

It’s all too easy to lose hope in the face of all the bad news about climate change and the destruction of the environment these days. Getting involved and taking action even on a small scale in your local community can help you feel more positive.

Check out some environmental groups you may want to become involved with.

We can also all continue to lobby the government and demand strong environmental policies and actions. We should accept nothing less and make sure we hold politicians accountable.