Every professional with even a passing familiarity with sustainability is aware of the Paris Agreement's goal to hold global warming to 2.0 degrees Celsius below pre-industrial levels and aim for 1.5 degrees Celsius.
These goals are laudable, but it is only part of the story. Focusing all our attention on net-zero emissions risks climate change tunnel vision.
We have already pushed past the danger zone on several planetary boundaries that are flashing red. Climate change is just one of these boundaries.
Planetary boundaries are a framework to describe limits to the impacts of human activities on Earth’s systems. Beyond these limits, these systems may not be able to self-regulate. In addition to climate change, these boundaries include ocean acidification, biosphere integrity, land-system change, and freshwater change. You can see from the graphic from the Stockholm Resilience Center that we are already on the bad side of 6 of 9 planetary boundaries.
The longer we stay outside of these planetary boundaries, the more we will experience famine, drought, extreme heat, extreme weather, and the loss of ecosystems and biodiversity.
The planetary boundaries are:
Climate change – Greenhouse gases in the atmosphere trap heat, which will lead to increased heat, more extreme weather events, sea level rise, more flooding, more drought, water scarcity, and increased population displacement.
Novel entities – Things introduced into the environment by human beings that are disruptive to Earth’s systems. Think plastics, which have a damaging impact on ecosystems.
Biochemical flows – This mainly involves the nitrogen and phosphorus cycles, which have been used on an industrial scale in things like fertilizers and pesticides. When these chemicals are too highly concentrated in ecosystems they can destroy those ecosystems.
Freshwater use – We have crossed this planetary boundary because the human use of water has disrupted the flow of the hydrological cycle that refreshes the water resources of the world.
Land system change – This refers to the changes in the landscape that humans have made on earth. The most prominent land use problem is deforestation, as forests support many natural systems on which we depend.
Biosphere integrity – This refers to the diversity and health of life on Earth. We are operating outside the safe zone here as we are in the sixth great extinction on Earth.
Stratospheric Ozone Depletion – The ozone layer in the stratosphere absorbs dangerous ultraviolet radiation from the sun. This planetary boundary is in the safe zone after governments came together in the 1980s to ban ozone-depleting substances.
Atmospheric Aerosol Loading – Atmospheric aerosols are particulate matter or pollution in the atmosphere. They can come from natural sources such as volcanoes, but also from human activity. Aerosols impact cloud formation and atmospheric circulation.
Ocean acidification – Increased CO2 emissions are making the ocean acidic because the oceans absorb that CO2, making the pH of the oceans more acidic. In time this will make it impossible for marine life with shells to survive. This will cause a collapse of the food chain in the oceans, with devastating consequences for marine life as well as humans.
What we can do.
Climate change – Stop producing greenhouse gas emissions and remove them from the atmosphere.
Novel entities – Stop producing novel entities like plastics and move to substitutes.
Ozone – Currently in the safe zone.
Aerosol loading – Currently in the safe zone.
Ocean acidification – We are near the danger zone. This is highly tied to climate change.
Biochemical flows – Greatly reduce the use of fertilizers and pesticides. If they are used, contain them.
Freshwater use – Water conservation should be part of every water use process.
Land uses – More protection of our land to ensure it is being used in ways to help, not harm.
Biodiversity loss – Protections for our biodiversity.
The good news is that many of these planetary boundaries are huge systems that interact with each other. For example, mitigating climate change slows ocean acidification. Lowering beef production, which is the main reason for deforestation (land use) helps tackle climate change, freshwater use, and biochemical flows.
We need to move beyond just climate change to properly address the environmental problems we face, but once we address one problem, it becomes easier to address the others.
To whom is this relevant?
Companies attempting to understand the broader landscape of environmental risks.
Investors who are looking to better understand how natural systems interact.
Policymakers with the responsibility of protecting our natural resources.
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