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Researchers have investigated the relevancy of the footprints concept and how it can be improved.
‘Carbon footprints’ are estimates of emissions of greenhouse gases in a specific setting, such as the activities of individuals, households, whole populations, governments, non-governmental organizations, companies, processes, and parts of industry sectors. The purpose of these footprints is to inform decision-makers — whether running a nation, a business or a household — and encourage them to reduce the size of their footprint, that is, the amount of greenhouse gases they contribute to the atmosphere via the decisions they make about how they live and work.
Over time, ‘carbon footprint’ has come to mean more than just carbon dioxide (CO2) but emissions of all greenhouse gases, including carbon dioxide methane (CH4), nitrous oxide (N2O) and chlorofluorocarbons expressed as the amount (tonnes) of CO2 produced during a given period.
‘The quantification of footprints can be derived from a common basis of accounting for land use,’ said Meine van Noordwijk, lead author of a study of footprints published in the journal, Carbon Footprints, and senior distinguished fellow with the Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF). ‘It all starts from a land-cover classification that allows all land units to be mapped without double-counting or gaps so that area fraction, time-averaged carbon stocks and emissions of N2O and CH4 can be measured. This is the basis of national systems of greenhouse-gas accounting for the land-use sector. Use of land provides marketable commodities and these can be the basis of product-based accounting when other parts of their life-cycle are included and summed for the full footprint of food production as part of the global food system. When consumption is differentiated by societal groups or individuals, further footprint calculations become possible.’
To learn more about whether carbon footprints were accurate, were doing their job and could be improved, van Noordwijk and a team of researchers from CIFOR-ICRAF, Plant Production Systems at Wageningen University and Research, Agroforestry Research Group of Brawijaya University, and the School of Ecosystem and Forest Sciences at the University of Melbourne set out to answer three questions: 1) How were the operational definitions of various types of carbon footprints related to consistent accounting for greenhouse-gas emissions? 2) How were footprint concepts used as boundary objects in public and private decision-making? 3) How might footprint concepts be improved?
How is the operational definition of carbon footprints related to consistent accounting of emissions?
The team noted that measuring changes in concentrations of greenhouse gases in the atmosphere remains the primary check of consistency. This is true not only for national systems of accounting but also for carbon footprints of individuals, sectors and businesses. For any new type of footprint, write the authors, the first question should be ‘does it add up?’.
The team also found that emissions embodied in trade remain a major challenge for national accounting systems to capture but, for individual carbon footprints, life-cycle analyses of the traded products can provide consistent data.
Two aspects influence the relationship between greenhouse gas emissions and climate change: the declining capacity of oceans and terrestrial sinks to absorb additional atmospheric carbon; and the effects of air pollution that acts as a cooling gas but is otherwise undesirable. These remain largely outside national accounting systems and the commonly used footprint-accounting methods yet these impacts are important.
Finally, in answer to their first question, the team questioned the inclusion in some footprint calculations of indirect land-use changes — such as when the cultivation of crops for bio-energy displaces production for food and feed — because these usually depend on inference and a categorization of products rather than on addressing the drivers of the changes to land use.
How were footprint concepts used as boundary objects in public and private decision-making?
‘Footprints can function as boundary objects because they are entities that enhance the capacity of an idea, theory or practice to translate across culturally defined boundaries,’ said van Noordwijk. ‘For example, between communities of knowledge or practice. The derivation and use of footprints is a form of boundary work and has to meet quality criteria of credibility, salience and legitimacy.’
The team found that the ‘public appeal and rhetorical value’ of carbon footprints ‘may well exceed transparency and reproducibility of current operational metrics’. In other words, the concept might be more attractive, and less accurate, than the reality.
And because carbon footprints isolate a chain or system of emissions, they should be ‘joined up’ with water footprints and impact on biological diversity so that consumers, and producers, can make better-informed choices.
How might footprint concepts be improved?
According to the researchers, ‘multifunctionality of land use’ — treating an entire landscape as a single entity to manage for low emissions in a balanced way — is an under-rated way of reconciling humanity’s ambitions and our planet’s capacity.
‘It’s still a challenge for commonly used carbon and footprint systems to account for the multiple uses of a given landscape,’ said Pham Thu Thuy, one of the co-authors and a senior scientist who leads the Climate Change, Energy and Low-Carbon Development team at CIFOR-ICRAF. ‘This is partly because there are functions in a landscape that, apart from emission of greenhouse gases, involve flows of goods and services throughout the landscape and beyond, which have their own rules of scale that link local to global and vice versa.’
To improve the concept of footprints, the team recommend testing and improving consistency among footprint estimates so that they add up to global net emissions. There should also be accompanying analysis of synergies, trade-offs and interactions among the various components of an overarching ecological footprint.
‘It would be useful to further explore boundary work and the way footprint data are used in societal change,’ said van Noordwijk. ‘And zooming in on the specific challenges of footprint accounting for multifunctionality of land use in relation to the United Nations’ Sustainable Development Goals.’
Read the journal article
Van Noordwijk M, Pham TT, Leimona B, Duguma LA, Baral H, Khasanah N, Dewi S, Minang PA. 2022. Carbon footprints, informed consumer decisions and shifts towards responsible agriculture, forestry and other land uses? Carbon Footprints 1:4.
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