Footprints

by

Alessandro Galli

• LAST REVIEWED: 30 November 2015
• LAST MODIFIED: 30 November 2015
• DOI: 10.1093/obo/9780199363445-0046

Introduction

Since the turn of the 21st century, the term “footprint” has become very popular and entered in our daily vocabulary as a metaphor for impact, usually referring to the impact of humans on the Earth ecosystem. Such metaphoric meaning of the term footprint dates back to the early 1990s and has its origins in the introduction, within the scientific arena, of a specific methodology called “Ecological Footprint.” Since then, the term has gained popularity arriving at the common meaning it has today. More recently, building on the appeal and immediateness of the term and the popularity gained by the Ecological Footprint methodology, a few other indicators have been proposed in the scientific arena, which have been named after the term “footprint.” I thus refer here to these indicators as “Footprint-type” indicators, or simply footprints. These indicators are all characterized by the adoption of a consumer-based approach, which intends to inform users about the pressure (or impact) human activities place on the Earth ecosystem or specific ecosystem’s compartments. Such consumer-based approach originates from the realization that, in the globalized world of today, the place of production/extraction of resources and that of their consumption substantially differ (primarily mediated through international trade) and thus environmental impacts are often manifesting far away from the places in which their root causes (i.e., their drivers) are taking place. In light of their consumer-based approach, Footprint-type indicators enable users to connect human consumption behaviors with the diverse impacts caused by the production activities behind them. They are useful in complementing territorial-based approaches by including all of the drivers of human impact on the Earth ecosystems associated with consumption activities and can thus provide complementary information for the formulation of international environmental policy frameworks.

General Overview

The works in this section provide overviews and introductions to each of the currently existing Footprint-type indicators. The first of these indicators to be introduced in the scientific literature was, in the 1990s, the Ecological Footprint (Wackernagel and Rees 1996), which builds on the seminal work Vitousek, et al. 1986 on human appropriation of the products of photosynthesis (see Ecological Footprint (EF)). In the early 2000s, growing global attention on the climate change issue led to an increased focus on carbon: multiple authors started speaking about Carbon Footprint (see Carbon Footprint (CF)), although this concept was formalized into a proper indicator only toward the end of the decade (Wiedmann and Minx 2008). Around the same period, the Water Footprint method (see Water Footprint (WF)) was developed in response to the need for a consumption-based indicator of freshwater use (Hoekstra 2003). While the Ecological Footprint looks at multiple human pressures concurrently, Carbon and Water Footprint have been conceived to have a restricted range of analysis and focus on specific issues/domains. All footprints have a consumer-based approach (Wiedmann 2009). Perhaps because of their domain-specific nature, Carbon and Water Footprints have gained popularity over the last few years, encouraging the proliferation of other domain-specific Footprint-type indicators, such as the Land, Nitrogen, Material, and Chemical Footprints (see Recently Emerging Footprints). Finally, in the 2010s, the possibility to combine Footprint-type indicators into a suite of indicators (namely, a Footprint Family) has been debated (Galli, et al. 2012) (see also Integrated Footprint Approaches). As Footprint-type indicators have been introduced at different point in times since the late 1990s, they are not homogeneously represented in the scientific literature. This is represented in the following sections of this bibliography, in which the various indicators have been reviewed in order of prominence in the academic literature. As you will read in the following sections, it emerges that three Footprint indicators have been primarily investigated, namely Ecological, Carbon, and Water Footprint; thus, a specific section is dedicated to each one of them. Conversely, the other footprints have been introduced only very recently and they are thus grouped under a single review section (see Recently Emerging Footprints).

• Galli, Alessandro, Thomas Wiedmann, Ertug Ercin, et al. 2012. Integrating Ecological, Carbon and Water Footprint into a “Footprint Family” of indicators: Definition and role in tracking human pressure on the planet. Ecological Indicators 16:100–112.

  DOI: 10.1016/j.ecolind.2011.06.017

  This academic paper presents a useful overview of the research questions and main characteristics of selected Footprint indicators. It also provides a review of their complementary and overlapping characteristics and the policy context within which they can be applied.

• Hoekstra, Arien Y., ed. 2003. Virtual water trade: Proceedings of the International Expert Meeting on Virtual Water Trade. Delft, The Netherlands, 12–13 December 2002. Value of Water Research Report Series 12. Delft, The Netherlands: UNESCOIHE.

  These proceedings constitute a detailed overview of the state of the art in the field of virtual water trade and introduce the Water Footprint concept as a tool to establish the link between water consumption patterns and the corresponding impacts on water systems.

• Vitousek, Peter M., Paul R. Ehrlich, Anne H. Ehrlich, et al. 1986. Human appropriation of the products of photosynthesis. BioScience 36:363–373.

  DOI: 10.2307/1310258

  This academic paper represents one of the most important contribution to the debate around human appropriation (and domination) of the biosphere’s resources. Its publication ignited the debate around this issue and opened up an entirely new field of scientific research.

• Wackernagel, Mathis, and William Rees. 1996. Our Ecological Footprint: Reducing human impact on the Earth. Gabriola Island, BC: New Society.

  This book introduces the Ecological Footprint concept and it is an ideal introduction for undergraduates and the wider public. Its publication has contributed to the public debate on the limits to the human use of natural capital and opened up the field of work on Ecological Footprint and Footprint-type indicators.

• Wiedmann, Thomas. 2009. A review of recent Multi-Region Input–Output models used for consumption-based emission and resource accounting. Ecological Economics 69:211–222.

  DOI: 10.1016/j.ecolecon.2009.08.026

  This academic paper provides a review of existing models for consumer-based accounting. It provides an interesting reading to get insight on the emerging importance of consumer-based accounting.

• Wiedmann, Thomas, and Jan Minx. 2008. A definition of “Carbon Footprint.” In Ecological economics research trends. Edited by Carolyn C. Pertsova, 1–11. Hauppauge, NY: Nova Science.

  This book chapter originates from the realization of the lack of clarity around the Carbon Footprint concept despite its widespread use across the media and in climate change debates. It thus attempts to provide a scientific definition for this concept, based on commonly accepted accounting principles and modeling approaches.