Greenhouse gases (GHGs) present in the atmosphere play a crucial role in regulating the climate. They trap a significant portion of solar energy (infrared radiation) that would otherwise be reflected from the Earth back into space. This phenomenon is called the greenhouse effect. It is thanks to this effect that the average temperature on Earth is around 15°C. Without this greenhouse effect, it would be around -18°C.
However, since the industrial era, this greenhouse effect has been significantly disrupted by human activities, particularly due to the use of fossil fuels. While this may seem evident to all of us, it is important to concretely illustrate what the natural carbon cycle is and the impact of human activities on the climate. This is what we will endeavor to explore in this article.
THE NATURAL CARBON CYCLE
The carbon cycle encompasses the transfer of carbon atoms among the Earth's various carbon sink: the atmosphere, lithosphere, hydrosphere, and biosphere. This movement occurs through a combination of geological and biochemical/chemical processes. These natural processes govern the flow of carbon in its gaseous (carbon dioxide), solid (organic matter and carbonate rocks), and liquid (dissolved carbon dioxide in water) forms, thereby maintaining equilibrium within the Earth's carbon system.
The natural carbon cycle involves several key processes:
Photosynthesis: plants, algae, and some bacteria absorb carbon dioxide (CO2) from the atmosphere and, using sunlight, convert it into organic matter (glucose), releasing oxygen as a byproduct.
Respiration: animals and plants consume this organic matter for energy, releasing CO2 back into the atmosphere.
Decomposition: when organisms die, decomposers like bacteria and fungi break down their bodies, returning carbon to the soil and atmosphere.
Ocean uptake: oceans absorb CO2 from the atmosphere. Some of this carbon is used by marine organisms for photosynthesis, while the rest can form sediments or be released back into the atmosphere.
Volcanic activity: volcanic eruptions release stored carbon from the Earth’s mantle into the atmosphere.
Naturally, the Earth warms up through the greenhouse effect combined with a natural imbalance in carbon exchanges of approximately 0.5 gigatons per year. But this natural imbalance is nothing compared to the imbalance caused by human activities.
DISRUPTION BY ANTHOPOGENIC ACTIVITIES
Human activities, particularly since the industrial revolution, have significantly disrupted the natural carbon cycle. According to the Intergovernmental Panel on Climate Change (IPCC), since 1900, global surface temperatures have risen by 1.1°C, a phenomenon unequivocally caused by human activities and mainly by GHG emissions. With no immediate and drastic measures to reduce GHG emissions within this decade, global warming could reach more than 3.2°C by the end of the century, in comparison to the pre-industrial era.
The Paris Agreement, adopted by 195 countries and the EU in 2015, during the COP21, represents a landmark in the global effort to address climate change, providing a universal framework for all countries to take ambitious climate actions and limit global warming to 1.5°C above pre-industrial levels.
According to the report by the European Union's Emissions Database for Global Atmospheric Research (EDGAR) published in 2023, global GHG emissions caused by human activities reached a total of 53.8 gigatonnes in 2022. This includes emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases used in various industrial applications, such as refrigerators, which are potent greenhouse gases even more powerful than CO2.
However, carbon dioxide remains the main gas responsible for climate disruption. Indeed, from 2013 to 2022, CO2 emissions caused by human activities averaged 40 gigatonnes. While the Earth is resilient and capable of absorbing a portion of these emissions, the below schematic clearly shows an imbalance between emissions and carbon sinks, creating an excess of more than 18 Gt of CO2 per year in the atmosphere, which cannot be naturally absorbed.
To get an idea, this corresponds roughly to the average annual emissions of China (15.7 Gt in 2022) and the EU (3.6 Gt in 2022) combined! To achieve carbon neutrality, approximately 18 Gt CO2 would need to be reduced or absorbed each year. This highlights the immense challenge posed by climate change and the necessity for states, businesses, and individuals to take immediate and ambitious actions to restore the natural balance of the carbon cycle.
The main disrupting human activities relate to:
Burning fossil fuels: the combustion of coal, oil, and natural gas for energy releases large amounts of CO2 into the atmosphere. Fossil fuels take millions of years to form, and their rapid consumption by humans far exceeds the Earth's ability to replenish them, leading to a significant imbalance. This has increased atmospheric CO2 levels dramatically from pre-industrial levels of approximately 280 parts per million (ppm) to over 410 ppm today, as per the NOAA's Earth System Research Laboratory (National Oceanic and Atmospheric Administration).
Deforestation: forests acting as carbon sinks have suffered massive deforestation, reducing their ability to absorb CO2, thus increasing the concentration of CO2 in the atmosphere. Although the rate of deforestation has slowed down in recent years, the world has lost about 420 million hectares of forests since 1990 according to the Food and Agriculture Organisation (FAO) and 17% of the Amazon rainforest has been lost in the last 50 years, according to the Rainforest Alliance.
Industrial processes: cement production, steelmaking, and other industrial processes emit significant amounts of CO2 and other greenhouse gases.
Agriculture: agricultural practices release methane (CH4) and nitrous oxide (N2O), both potent greenhouse gases. Livestock digestion (enteric fermentation) and manure management are major sources of methane, while synthetic fertilizers contribute to nitrous oxide emissions.
WHAT ARE THE SOLUTIONS TO RESTORE THE NATURAL CARBON CYCLE?
We are all aware of the immense challenge that climate change poses to humanity, to all living beings in general, but also to the global economy. Restoring the natural carbon cycle is the greatest challenge in human history. To achieve this, two concrete objectives must be set:
Reducing anthropogenic carbon flows: involves significantly cutting down emissions of carbon dioxide and other greenhouse gases resulting from human activities as detailed above. This concretely means taking individual and collective actions, both locally and globally, to reduce consumption and rethink production. While initial actions can be undertaken at the level of states and companies, it is up to everyone to contribute to this reduction. The global emissions decrease in 2020 due to the COVID-19 pandemic (-3.7% compared to 2019), shows a trend that should be considered the norm each year to reach the objectives set by the IPCC and keep the global temperature increase within the 1.5°C limit. At COP28 in December 2023, the parties agreed to transition away from fossil fuels. Beyond pledges, governments and businesses need to turn this into real-economy outcomes.
Restore the natural carbon sinks: reducing emissions is the first part of the equation, but natural carbon sinks that take thousands or millions of years to constitute, have been disrupted by human activities in a couple of decades only. As we have seen, this disruption has accelerated natural global warming by increasing the concentration of greenhouse gases into the atmosphere. In addition to reducing the inflow of carbon into the atmosphere, it is necessary to restore and increase the outflow of carbon from the atmosphere to the biosphere, hydrosphere, and especially the lithosphere. At Apolownia, we firmly believe that this must be achieved through the implementation of ambitious decarbonization projects aimed at restoring and conserving natural ecosystems and reestablishing their role as natural carbon sinks.
ABOUT APOLOWNIA
Apolownia is a mission-driven company committed to making a significant impact in the climate sector.
We support businesses and funds willing to engage in long-term and impactful decarbonization strategies - within and beyond their own value chain - by designing, implementing and monitoring science-based carbon reduction projects that restore natural ecosystems.
Through technology and innovative solutions, we aim at shaping a resilient and environmentally friendly world, by encouraging the decarbonization of the economy and supporting social and environmental initiatives.
You can drive positive change for the climate, biodiversity and local communities.
Contact us to engage or for more information. Find us on www.apolownia.com.
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