Carbon footprint

). They may report them per year, per person, per kilogram of protein, per kilometer travelled, and so on. In the definition of carbon footprint, some scientists include only CO2. But more commonly they include several of the notable greenhouse gases. They can compare various greenhouse gases by using carbon dioxide equivalents over a relevant time scale, like 100 years. Some organizations use the term greenhouse gas footprint or climate footprint to emphasize that all greenhouse gases are included, not just carbon dioxide. The Greenhouse Gas Protocol includes all of the most important greenhouse gases. "The standard covers the accounting and reporting of seven greenhouse gases covered by the Kyoto Protocol – carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PCFs), sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3)." In comparison, the IPCC definition of carbon footprint in 2022 covers only carbon dioxide. It defines the carbon footprint as the "measure of the exclusive total amount of emissions of carbon dioxide (CO2) that is directly and indirectly caused by an activity or is accumulated over the lifecycle stages of a product." That publication included only carbon dioxide in the definition of carbon footprint. It justified this with the argument that other greenhouse gases were more difficult to quantify. This is because of their differing global warming potentials. They also stated that an inclusion of all greenhouse gases would make the carbon footprint indicator less practical. appear less harmful for the climate than they actually are. == Types of greenhouse gas emissions ==

scopes and emissions across the value chain, showing upstream activities, reporting company and downstream activities. The greenhouse gas protocol is a set of standards for tracking greenhouse gas emissions. The standards divide emissions into three scopes (Scope 1, 2 and 3) within the value chain. Greenhouse gas emissions caused directly by the organization such as by burning fossil fuels are referred to as Scope 1. Emissions caused indirectly by an organization, such as by purchasing secondary energy sources like electricity, heat, cooling or steam are called Scope 2. Lastly, indirect emissions associated with upstream or downstream processes are called Scope 3. Direct carbon emissions (Scope 1) Direct or Scope 1 carbon emissions come from sources on the site that is producing a product or delivering a service. An example for industry would be the emissions from burning a fuel on site. On the individual level, emissions from personal vehicles or gas-burning stoves are Scope 1. Indirect carbon emissions (Scope 2) Indirect carbon emissions are emissions from sources upstream or downstream from the process being studied. They are also known as Scope 2 or Scope 3 emissions. Examples of downstream carbon emissions include any end-of-life process or treatments, product and waste transportation, and emissions associated with selling the product. The GHG Protocol says it is important to calculate upstream and downstream emissions. There could be some double counting. This is because upstream emissions of one person's consumption patterns could be someone else's downstream emissions Other indirect carbon emissions (Scope 3) Scope 3 emissions are all other indirect emissions derived from the activities of an organization. But they are from sources they do not own or control. Scope 3 emission sources include emissions from suppliers and product users. These are also known as the value chain. Transportation of goods, and other indirect emissions are also part of this scope. The International Sustainability Standards Board is developing a recommendation to include Scope 3 emissions in all GHG reporting. == Purpose and strengths ==

The current rise in global average temperature is more rapid than previous changes. It is primarily caused by humans burning fossil fuels. The increase in greenhouse gases in the atmosphere is also due to deforestation and agricultural and industrial practices. These include cement production. The two most notable greenhouse gases are carbon dioxide and methane. Greenhouse gas emissions, and hence humanity's carbon footprint, have been increasing during the 21st century. The Paris Agreement aims to reduce greenhouse gas emissions enough to limit the rise in global temperature to no more than 1.5 °C above pre-industrial levels. The carbon footprint concept makes comparisons between the climate impacts of individuals, products, companies and countries. A carbon footprint label on products could enable consumers to choose products with a lower carbon footprint if they want to help limit climate change. For meat products, as an example, such a label could make it clear that beef has a higher carbon footprint than chicken. Therefore, ignoring Scope 3 emissions makes it impossible to detect all emissions of importance, which limits options for mitigation. Large companies in sectors such as clothing or automobiles would need to examine more than 100,000 supply chain pathways to fully report their carbon footprints. The importance of displacement of carbon emissions has been known for some years. Scientists also call this carbon leakage. The idea of a carbon footprint addresses concerns of carbon leakage which the Paris Agreement does not cover. Carbon leakage occurs when importing countries outsource production to exporting countries. The outsourcing countries are often rich countries while the exporters are often low-income countries. Carbon leakage and related international trade have a range of environmental impacts. These include increased air pollution, biodiversity loss, raw material usage, and energy depletion. Scholars have argued in favour of using both consumption-based and production-based accounting. This helps establish shared producer and consumer responsibility. Currently countries report on their annual GHG inventory to the UNFCCC based on their territorial emissions. This is known as the territorial-based or production-based approach. The Paris Agreement currently does not require countries to include in their national totals GHG emissions associated with international transport. These emissions are reported separately. They are not subject to the limitation and reduction commitments of Annex 1 Parties under the Climate Convention and Kyoto Protocol. The carbon footprint methodology includes GHG emissions associated with international transport, thereby assigning emissions caused by international trade to the importing country. == Underlying concepts for calculations ==

The calculation of the carbon footprint of a product, service or sector requires expert knowledge and careful examination of what is to be included. Carbon footprints can be calculated at different scales. They can apply to whole countries, cities, neighborhoods and also sectors, companies and products. Several free online carbon footprint calculators exist to calculate personal carbon footprints. Software such as the "Scope 3 Evaluator" can help companies report emissions throughout their value chain. The software tools can help consultants and researchers to model global sustainability footprints. In each situation there are a number of questions that need to be answered. These include which activities are linked to which emissions, and which proportion should be attributed to which company. Software is essential for company management. But there is a need for new ways of enterprise resource planning to improve corporate sustainability performance. To achieve 95% carbon footprint coverage, it would be necessary to assess 12 million individual supply-chain contributions. This is based on analyzing 12 sectoral case studies. The Scope 3 calculations can be made easier using input-output analysis. This is a technique originally developed by Nobel Prize-winning economist Wassily Leontief. Consumption-based emission accounting traces the impacts of demand for goods and services along the global supply chain to the end-consumer. It is also called consumption-based carbon accounting. Consumption-based accounting redistributes the emissions from production-based accounting. It considers that emissions in another country are necessary for the home country's consumption bundle. Analysis of global supply chains is possible using consumption-based accounting with input-output analysis assisted by super-computing capacity. Leontief created Input-output analysis (IO) to demonstrate the relationship between consumption and production in an economy. It incorporates the entire supply chain. It uses input-output tables from countries' national accounts. It also uses international data such as UN Comtrade and Eurostat. Input-output analysis has been extended globally to multi-regional input-output analysis (MRIO). Innovations and technology enabling the analysis of billions of supply chains made this possible. Standards set by the United Nations underpin this analysis. The analysis enables a Structural Path Analysis. This scans and ranks the top supply chain nodes and paths. It conveniently lists hotspots for urgent action. Input-output analysis has increased in popularity because of its ability to examine global value chains. Combination with life cycle analysis (LCA) Life cycle assessment (LCA) is a methodology for assessing all environmental impacts associated with the life cycle of a commercial product, process, or service. It is not limited to the greenhouse gas emissions. It is also called life cycle analysis. It includes water pollution, air pollution, ecotoxicity and similar types of pollution. Some widely recognized procedures for LCA are included in the ISO 14000 series of environmental management standards. A standard called ISO 14040:2006 provides the framework for conducting an LCA study. ISO 14060 family of standards provides further sophisticated tools. Also the latest standard, ISO 14064:2018 has the right set of tools that will help reduce Carbon Emissions in Corporations. These are used to quantify, monitor, report and validate or verify GHG emissions and removals. Greenhouse gas product life cycle assessments can also comply with specifications such as Publicly Available Specification (PAS) 2050 and the GHG Protocol Life Cycle Accounting and Reporting Standard. An advantage of LCA is the high level of detail that can be obtained on-site or by liaising with suppliers. However, LCA has been hampered by the artificial construction of a boundary after which no further impacts of upstream suppliers are considered. This can introduce significant truncation errors. LCA has been combined with input-output analysis. This enables on-site detailed knowledge to be incorporated. IO connects to global economic databases to incorporate the entire supply chain. == Problems ==

Shifting responsibility from corporations to individuals Critics argue that the original aim of promoting the personal carbon footprint concept was to shift responsibility away from corporations and institutions and on to personal lifestyle choices. The fossil fuel company BP ran a large advertising campaign for the personal carbon footprint in 2004 which helped popularize this concept. Geoffrey Supran and Naomi Oreskes of Harvard University argue that concepts such as carbon footprints "hamstring us, and they put blinders on us, to the systemic nature of the climate crisis and the importance of taking collective action to address the problem". While the focus on individual behaviour has shaped public discourse, scientific assessments emphasize that this approach alone is insufficient. The IPCC notes that individual behavioural changes alone are insufficient to achieve deep emission reductions. In its Sixth Assessment Report (2023), the IPCC stated that "Demand-side measures and new ways of end-use service provision can reduce global GHG emissions in end-use sectors by 40–70% by 2050 compared to baseline scenarios" This highlights the need to combine lifestyle changes with systemic transitions—such as clean energy systems, electrification of transport and heating, and collective infrastructure solutions—to effectively address climate change. Reducing emissions through behaviour is important, but eliminating combustion altogether through systemic change is critical to long-term climate goals. Relationship with other environmental impacts A focus on carbon footprints can lead people to ignore or even exacerbate other related environmental issues of concern. These include biodiversity loss, ecotoxicity, and habitat destruction. It may not be easy to measure these other human impacts on the environment with a single indicator like the carbon footprint. Consumers may think that the carbon footprint is a proxy for environmental impact. In many cases this is not correct. There can be trade-offs between reducing carbon footprint and environmental protection goals. One example is the use of biofuel, a renewable energy source that can reduce the carbon footprint of the energy supply but can also pose ecological challenges during its production. This is because it is often produced in monocultures with ample use of fertilizers and pesticides. In fact, carbon footprint can be treated as one component of ecological footprint. It offers calculations that are either consumption-based, following the carbon footprint approach, or production-based. The database of the SCP-HAT tool is underpinned by input–output analysis. This means it includes Scope 3 emissions. The IO methodology is also governed by UN standards. and therefore it is comparable worldwide. Differing boundaries for calculations The term carbon footprint has been applied to limited calculations that do not include Scope 3 emissions or the entire supply chain. This can lead to claims of misleading customers with regards to the real carbon footprints of companies or products. == Reported values ==

Greenhouse gas emissions overview By products The Carbon Trust has worked with UK manufacturers to produce "thousands of carbon footprint assessments". As of 2014 the Carbon Trust state they have measured 28,000 certifiable product carbon footprints. This NGO has also developed a labelling scheme which "supports informed consumer choices and business procurement decisions". Food Plant-based foods tend to have a lower carbon footprint than meat and dairy. In many cases a much smaller footprint. This holds true when comparing the footprint of foods in terms of their weight, protein content or calories. A key driver of global carbon emissions is affluence. The IPCC noted that the wealthiest 10% in the world contribute between about one third to one half (36%–45%) of global GHG emissions. Researchers have previously found that affluence is the key driver of carbon emissions. It has a bigger impact than population growth. And it counters the effects of technological developments. Continued economic growth mirrors the increasing trend in material extraction and GHG emissions. "Industrial emissions have been growing faster since 2000 than emissions in any other sector, driven by increased basic materials extraction and production," the IPCC said. Transport There can be wide variations in emissions for transport of people. This is due to various factors. They include the length of the trip, the source of electricity in the local grid and the occupancy of public transport. In the case of driving the type of vehicle and number of passengers are factors. The EU average for 2007 was about 13.8 tonnes CO2e per person. For the USA, Luxembourg and Australia it was over 25 tonnes CO2e per person. In 2017, the average for the USA was about 20 metric tonnes CO2e per person. This is one of the highest per capita figures in the world. The footprints per capita of countries in Africa and India were well below average. Assuming a global population of around 9–10 billion by 2050, a carbon footprint of about 2–2.5 tonnes CO2e per capita is needed to stay within a 2 °C target. These carbon footprint calculations are based on a consumption-based approach using a Multi-Regional Input-Output (MRIO) database. This database accounts for all greenhouse gas (GHG) emissions in the global supply chain and allocates them to the final consumer of the purchased commodities. == Reducing the carbon footprint ==

Climate change mitigation Efforts to reduce the carbon footprint of products, services, and organizations help limit climate change. Such activities are called climate change mitigation. Reducing industry's carbon footprint s provide energy with a fairly low carbon footprint compared to fossil fuels. Carbon offsetting can reduce a company's overall carbon footprint by providing it with a carbon credit. This compensates the company for carbon dioxide emissions by recognizing an equivalent reduction of carbon dioxide in the atmosphere. Reforestation, or restocking existing forests that have previously been depleted, is an example of carbon offsetting. A carbon footprint study can identify specific and critical areas for improvement. It uses input-output analysis and scrutinizes the entire supply chain. Such an analysis could be used to eliminate the supply chains with the highest greenhouse gas emissions. == History ==

The term carbon footprint was first used in a BBC vegetarian food magazine in 1999, though the broader concept of ecological footprint, which encompasses the carbon footprint, had been used since at least 1992, as also chronicled by journalist William Safire in the New York Times. In 2005, fossil fuel company BP hired the large advertising campaign Ogilvy to popularize the idea of a carbon footprint for individuals. The campaign instructed people to calculate their personal footprints and provided ways for people to "go on a low-carbon diet". The carbon footprint is derived from the ecological footprint, which encompasses carbon emissions. the carbon footprint on its own is expressed in the weight of carbon emissions per time unit. William Rees wrote the first academic publication about ecological footprints in 1992. Other related concepts from the 1990s are the "ecological backpack" and material input per unit of service (MIPS). == Trends and similar concepts ==

The International Sustainability Standards Board (ISSB) aims to bring global, rigorous oversight to carbon footprint reporting. It was formed out of the International Financial Reporting Standards. It will require companies to report on their Scope 3 emissions. The ISSB has taken on board criticisms of other initiatives in its aims for universality. It consolidates the Carbon Disclosure Standards Board, the Sustainability Accounting Standards Board and the Value Reporting Foundation. It complements the Global Reporting Initiative. It is influenced by the Task Force on Climate-Related Financial Disclosures. As of early 2023, Great Britain and Nigeria were preparing to adopt these standards. The concept of total equivalent warming impact (TEWI) is the most used index for carbon dioxide equivalent (CO2) emissions calculation in air conditioning and refrigeration sectors by including both the direct and indirect contributions since it evaluates the emissions caused by the operating lifetime of systems. The Expanded Total Equivalent Warming Impact method has been used for an accurate evaluation of refrigerators emissions. == See also ==