Leaving a mark on the world of the future is a desire shared by virtually every human being. But there is at least one case in which the best thing we can do for the next generation is to make sure that our impact as is as imperceivable as possible, to the point of disappearing. This is certainly the case with our carbon footprint. What is meant by the term carbon footprint? The carbon footprint is a measure of the amount of greenhouse gas emissions released into the atmosphere by the activities of a person, company, city or state. In essence, it is a measure of how much we contribute to anthropogenic global warming. Or, to turn it into a positive, how much we contribute to slowing it down, if our carbon footprint is small. The footprint includes direct emissions caused by burning fossil fuels (in driving a car engine or heating a building, for example) and indirect emissions, such as those related to electricity consumed, if it comes from fossil fuels. And although by convention it is measured in tons of carbon dioxide (CO2) per year, it actually includes emissions of all gases that contribute to global warming. They include methane (which, in addition to being extracted from the ground, is also produced in considerable quantities by animals on intensive livestock farms, and is part of the global emissions total), nitrogen oxide, and chlorofluorocarbons (CFCs). The carbon and ecological footprints In the scientific literature on sustainability, the concept of carbon footprint was preceded by that of the ecological footprint, which was introduced in the early 1990s by the ecologists William Rees and Mathis Wackernagel. A "footprint" is, of course, a small portion of land where a visible mark is left. The ecological footprint is in fact the total area of land (or sea) required to sustain a population, and so its calculation also takes into consideration the water consumed and the land used for crops and livestock. When global warming and CO2 emissions became the focus of environmental sustainability studies, the ecological footprint measure fell into disuse, while the carbon footprint became a key tool for monitoring compliance with international agreements on emission reduction. Calculation methods There is no single method for calculating carbon footprint. It is a complex measurement that takes into account many factors, and it can be done at different scales. In general, rather than measured directly, the carbon footprint is estimated: whether it is of a state, a company or an individual, the carbon footprint is approximated based on criteria defined by the scientific community and international standards. The key reference is the guidelines and tools for national greenhouse gas inventories from the IPCC, the United Nations' International Panel on Climate Change. These guidelines provide average criteria for calculating greenhouse gas emissions and thus a nation's carbon footprint from its key statistical and economic indicators, and are used to define and monitor international climate agreements. Typical source data are the amount of fossil fuels consumed throughout the country during the course of a year, total electricity production, the value of industrial production, the division of land area between urban, forest and agricultural areas, the number of livestock raised, and so on. Once the total amount of emissions has been calculated, the so-called carbon sinks are subtracted from this figure. They refer to everything that was done during the same period to absorb carbon. If, for example, a country, an organization or individual has planted a certain number of trees during the year, their CO2 absorption power should be subtracted from the total. For each of these parameters, the IPCC provides conversion tables that make it possible to translate liters of diesel fuel, cubic meters of methane, hectares of cropland, numbers of livestock, square kilometers of new forests, into a single unit of measurement: grams of CO2 emitted (or absorbed). The notation CO2 e (Carbon dioxide equivalent) is often used, because emissions of different types are also "converted" into their CO2 equivalent. Carbon footprint measurement can be tailored to different needs and levels of detail and must consider the difference between the emissions of a certain project and its alternatives. For example, the construction of a bridge might have a significant carbon footprint in itself: but if its effect is to shorten the distance between two cities and reduce the number of kilometers traveled by cars passing between them, in the long run it may result in a reduction in emissions, and thus a negative footprint. The carbon footprint generated by a company Calculating their carbon footprint is now an essential step for medium-sized and large companies in many industries, and particularly for large listed companies that need to show their shareholders, through their Sustainability Report, their commitment to combating climate warming. The starting point is to identify and catalog all possible sources of emissions – from production facilities to offices, from data center servers to the car fleet, and so on – and collect as accurate data as possible on each of them. The company will then have to extract data from its electricity and water consumption bills, record fuel purchases and miles driven by its cars, record the tons of different types of waste disposed of, and so on. In the case of a farm, it will have to count its livestock (which produce methane, as previously stated), and the amounts of fertilizer or pesticides used (chemicals with a significant carbon footprint). In the case of a hi-tech company that uses large amounts of data, it will need to calculate the cloud storage space used. After that, for each of these parameters the company must use emission factors such as those provided by the International Energy Agency or the Environmental Protection Agency in the US. The calculation of a product's carbon footprint You may have come across an indication of a purchased product’s carbon footprint on its label. The calculation of this parameter at the individual product level is an important tool that enables individual consumers to guide sustainability policies with their own choices. They can choose – even in the case of consumer products such as food or clothing – brands that pay more attention to reducing emissions. The carbon footprint of an individual product is calculated using a methodology called Life Cycle Assessment (LCA). It measures all emissions caused by the generation or extraction of the raw materials needed for a product, be they, metals, precursor chemicals for a plastic product, grain or other crops for food products, and for all intermediate processing. Some examples? A cotton T-shirt has a footprint of 4 kg of CO2. A pair of shoes ranges from 10 to 15 kg and a pair of jeans reaches 20 kg. A tablet leaves a 50 kg footprint, a microwave oven 80 kg, and a conventional oven is almost 200 kg. A laptop can reach 350 kg. Motor vehicles are on another scale altogether: a luxury SUV goes over 26 tons of CO2. When it comes to food, apples and bananas have a footprint of less than 1 kg of CO2 per kg of product, palm oil comes in at 8 kg of CO2, meat ranges from 20 to 60 kg depending on how the animal in question is raised. How to calculate your carbon footprint All right, but how can I know my carbon footprint or that of my family? As with so many things in the world, there are online resources and apps (popular ones include MyEarth, CO2 tracker, Adva, Klima, Earth Hero) that enable you to do so, albeit in a way that is inevitably approximate. A good example in understanding how this happens is the online calculator developed by The Nature Conservancy. The first thing to do is to carefully monitor your consumption and activities. You need to have data to hand on the size of your home, its level of energy efficiency, how it is heated and lit. The gas bill tells us how many cubic meters we have consumed in a year, and a simple formula can translate that into the number of grams of CO2 emitted. Electricity bills are more complicated: in order to translate kW/h consumed into emissions, we would need to know precisely how much of the electricity we were supplied with came from fossil sources and how much from renewables. Unless the electricity in question is self-generated with solar panels, you can use an average based on the energy mix of the country you are in, and that is what apps and online calculators do. Other important data include how much we travel and how-how many trips by train, how many by plane, how many miles per year by car, how often we take buses or subways. What kind of food we buy: consuming a lot of meat, or large quantities of exotic fruits that arrive in our country after long journeys, increases our carbon footprint. Buying single-serving packages with lots of plastic has a larger footprint than buying large packages with biodegradable packaging. How we dispose of our waste also makes a big difference: sorting is a great way to reduce our footprint compared to people who throw everything in the same trash can. Finally, apps and online calculators typically ask us to estimate how much we spend per month on purchases other than food: clothes, electronic equipment and services of all kinds. Because the price of goods and services is very much tied to the energy required to produce them, there are in fact average estimates of the energy consumed (and thus the CO2 produced) for every euro of products or services on the market. The final result will tell us whether we are more or less "virtuous" than the average of our fellow citizens. According to official data from the European Commission, the per capita carbon footprint of Italians is now 5.41 tons of CO2 per year. This is significantly lower than in the past (it peaked at 8.47 tons in 2005), slightly less than the European average of 6.25 tons, and far less than the United States where each citizen emits an average of 14.24 tons per year. The impact of carbon footprint on the environment The reason why there are so many efforts to calculate and, more importantly, to reduce the carbon footprint of organizations and individuals can be explained easily. Every additional kg of CO2 in the atmosphere contributes to the greenhouse effect, whereby solar heat that reaches Earth is trapped in the atmosphere, rather than being dispersed back into space. This causes the Earth's average surface and sea temperatures to rise. IPCC data tell us that because of this effect, the average temperature of the Planet in the decade 2011-2020 was 1.09 degrees Celsius higher than in the pre-industrial era, and that it continues to rise by 0.2 degrees per decade. These increases are already having visible effects, such as an increased frequency of extreme weather events (floods, heat waves, exceptional precipitation and long periods of drought). Current international commitments aim to contain global warming to between 1.5 and 2 degrees Celsius above pre-industrial levels. Beyond that threshold, scientists believe that the Planet would be affected by a range of irreversible effects such as melting of the polar ice caps, acidification of the seas and changes in ocean currents, irreversible damage to coral reefs and reduction in fish populations, reduction or disappearance of many glaciers, and expansion of desert areas. The impact on the living conditions of humans would be considerable. Examples include: food crises due to reduced wheat, rice and corn harvests and increased spread of infectious diseases, which are more easily transmitted in warm climates. The sectors with the largest carbon footprints Inevitably, in a world SCENARIO still heavily dependent on fossil fuels and where the energy transition is underway but still in its infancy, most of the world's emissions come from the energy sector. According to data from the International Energy Agency, power generation emitted just under 15 gigatonnes of CO2 in 2022, followed by the industrial sector as a whole (9 giga tons), transportation (8), and the construction sector (5). These aggregate figures mask large differences, however. In the energy sector, for example, the growth of renewables prevented nearly 600 mega tons of CO2 emissions in the 2021-2022 biennium, and future projections speak of a steadily decreasing carbon footprint. The same is true in transportation, thanks to the spread of electric vehicles and the increased efficiency of the same cars with internal combustion engines. In the industrial sector, the core of the carbon footprint is in the so-called "hard-to-abate" sectors, such as steel, petrochemicals, or cement production. They alone account for 30% of the world's emissions, and by their nature they require a great deal of energy intensity that is not easily achieved with renewable sources. For the steel industry, for example, the best option for reducing the carbon footprint could be so-called green hydrogen, which is produced by separating hydrogen and oxygen from water by harnessing electricity from renewable sources. This is a process that in industrial settings would offer an important advantage over fossil fuels. Global initiatives for reducing humanity's carbon footprint The Paris Agreement, which was signed by the United Nations on December 12, 2015, is the key reference for all global policies to reduce emissions. In particular, it proposes keeping the global average temperature increase below 2°C compared to pre-industrial levels, doing everything possible to limit it to 1.5°C; increasing adaptive capacity to the adverse effects of climate change and promoting climate resilience; and securing the necessary financing for low-emission, climate-friendly development. The Paris Agreement was the starting point for continental – or national – scale policies: such as the European Green Deal, which aims to achieve climate neutrality in Europe by 2050 (i.e., a zero balance between CO2 emitted and absorbed); or the recent Build Back Better plan in the United States, which sets ambitious targets for renewable energy production, energy efficiency in buildings, and the electrification of the car fleet. FAQ What is the purpose of calculating the carbon footprint? It is used in order tounderstand how much a state, company, product or person is contributing to global warming. This makes it possible to monitor compliance with international commitments to combat climate change, and make more accurate projections of future global warming trends. What are the consequences of a high carbon footprint? Greenhouse gases released into the atmosphere contribute to the greenhouse effect, which traps solar heat in the atmosphere causing average land surface and sea temperatures to rise. This in turn causes extreme weather events and endangers the health of ecosystems. What is the carbon footprint of digital? It is a measure of the amount of emissions caused by activities conducted on the internet, and more generally by digital applications. In particular, data centers used for delivering cloud services (from email to cloud computing to social networks) result in high electricity consumption and therefore a high carbon footprint, if the energy used to power them doesn’t come from renewable sources. What are the water and ecological footprints? The water footprint is a measure of the amount of freshwater consumed over the course of a year by a business, community or individual, or used during the production cycle of a good or service. The ecological footprint, on the other hand, is an indicator that measures the extent of human impact on the natural environment in terms of natural resources consumed and waste produced, comparing it with the Planet's capacity to regenerate those resources.
