THE GREENHOUSE EFFECT
Through the Paris Agreement, countries around the world have agreed to limit global warming to well below 2 °C and aim to restrict it to a maximum of 1.5 °C compared to pre-industrial levels. Global average temperatures have already risen by 1.2 °C. The primary reason for this temperature increase is the rising levels of various greenhouse gases in the atmosphere, driven by various human-induced processes. These gases temporarily trap some of the sun’s heat, which would otherwise radiate directly into space. This phenomenon is known as the greenhouse effect, a natural process that creates the conditions for life on Earth. The problem is that emissions have now reached such high levels that they lead to an intensified greenhouse effect, resulting in climate change.
There are several greenhouse gases contributing to global warming. In Climate Call, we focus on the most important ones: carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
CARBON DIOXIDE primarily stems from the combustion of fossil fuels (coal, oil, and natural gas, also known as fossil gas) and emissions from peatlands used as agricultural land. Peatland is a type of soil with a high organic content containing carbon. When the soil is disturbed (for example, during plowing and use for agriculture), the organic material breaks down, releasing carbon dioxide into the atmosphere.
METHANE mainly originates from the digestive systems of ruminant animals (such as cows and sheep) and from manure in livestock stables and storage areas (such as slurry pits). Methane-producing microorganisms thrive in the oxygen-free environments of ruminant stomachs and manure storage facilities.
NITROUS OXIDE primarily comes from synthetic fertilizer production, peatlands used as agricultural land, and the application of synthetic and animal manure on fields and pastures. Microorganisms in the soil play a crucial role in this process. In the soil, there are microorganisms that feed on breaking down nutrient-rich nitrogen compounds in manure, producing nitrous oxide in the process.
Different greenhouse gases contribute to global warming to varying degrees due to their differing abilities to absorb incoming solar radiation and their varying lifespans in the atmosphere. To compare and aggregate different greenhouse gases, they are often converted into what are known as carbon dioxide equivalents (CO2e) by multiplying them by a Global Warming Potential (GWP).
Various methods exist to calculate the cumulative climate impact of emissions from different greenhouse gases. In Climate Call, we use the GWP 100 method, which calculates climate impact over a 100-year period. All emissions are expressed in kg CO2e (even when only carbon dioxide is emitted). When we refer to “climate impact”, we mean the total emissions in kg CO2e.
According to GWP 100, 1 kg of methane has 27 times the climate impact of 1 kg of carbon dioxide, and 1 kg of nitrous oxide has 273 times the climate impact of 1 kg of carbon dioxide, over the course of 100 years. That means that 1 kg of methane is equivalent to 27 kg CO2e, and 1 kg of nitrous oxide is equivalent to 273 kg CO2e.