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Carbon Neutrality (1/2): A global objective

Charles Dubouix

Carbon Neutrality (1/2): A global objective Carbon Neutrality is a scientific concept

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KEY TAKEAWAYS

Carbon neutrality is only scientifically defined at a global scale, as the balance between human emissions and the capture of CO2.

What is carbon neutrality?

Scientific definition

Carbon neutrality, also known as net zero, involves balancing anthropogenic (human-caused) CO2 emissions and anthropogenic CO2 removals (sequestration, sinks) on a global scale.

Achieving carbon neutrality is an absolute prerequisite for stabilizing global carbon concentrations and mitigating the greenhouse effect and climate change. To meet the Paris Agreement, this global objective must be reached before 2050.

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The Bathtub analogy The atmosphere can be compared to a giant bathtub whose water level represents the amount of carbon found there. As the atmosphere has a finite and invariant volume (like our bathtub), the concentration of CO2 is the result of emissions and removals. 📅 Prior to 1850, and the industrial revolution, the level was stable, maintained around 2240 gtCO2, corresponding to a CO2 concentration in the atmosphere of 277 ppm (parts per million). ⌛ In a century and a half, human activities have added about 917 gtCO2 to the atmosphere through fossil fuel combustion, industrial processes and deforestation. The concentration of CO2 in the atmosphere reached 414 ppm, a 40% increase! This surplus of carbon induces an increase in the average temperature on the Earth’s surface. To meet the 1.5°C or 2°C targets, we need to ensure that the tub does not “overflow”.

In a nutshell:

🛁 The atmosphere can be considered as a bathtub that contains CO2.

🌊 ☝️ The flow filling the bathtub is anthropogenic (=human) emissions of CO2. 🌊 👇 The flow draining the bathtub is anthropogenic (=human) sinks of CO2. ⚖️ Carbon neutrality refers to the time when the volume of water leaving the bath through the sink match the volume added by the pipe.

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Do you think that we are heading toward carbon neutrality?

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Surprise…

By definition there are only two paths to achieve Carbon Neutrality

📉 Reducing CO2 emissions

⛽ Burning less fossil fuels

🔥 Less deforestation (93% of the wood from deforestation is burnt)

📈 Increasing carbon sinks

Nature based capture

🌳 Forest: growing forests capture CO2. Yet, deforestation mostly because of agricultural expansion keeps reducing the global surface of forests.

🌊 Ocean: mostly due to CO2 solubility (C02 disolves in water, causing ocean acidification), but also phytoplancton photosynthesis.

🌱 Soils: depending on farming practices, soils can either absorb or emit CO2.

Technological capture

🤷‍♂️ Many technological paths : Carbon Capture and Storage (CCS), Direct Air Capture…

⚠️ Bottom line: not mature enough and energy intensive. But, imperative on the long run.

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Go to the second article on Carbon Neutrality to discover how a company can become carbone neutral