The Ecological Footprint’s emergence was inspired by a simple question: “how much do people take compared to what Earth can regenerate?” While the question has remained the same since the early 1990s, the methodology has evolved to improve the accuracy and precision of the answer.
Over the decades, Ecological Footprint results and its applications have become more popular. For instance, for the 2021 Earth Overshoot Day campaign, which is based on results from the National Footprint and Biocapacity Accounts, we could track over 5,700 media stories in more than 100 countries. Additionally, over 250 academic papers on the Footprint have been published every year for the last decade.
Wide exposure invariably generates criticism. Undoubtedly, there is room for improvement in the methodology, an aspect continuously monitored and discussed by the Science Advisory Committee to the National Footprint and Biocapacity Accounts. Relevant criticism is healthy and welcome. It drives the scientific progress.
Based on simple principles
Ecological Footprint and biocapacity accounting apply a basic scientific principle: add up all demands that compete for biologically productive space. The science is so basic that we call it “pedestrian.” But of course, the devil is in the details, particularly with respect to the most comprehensive application, the National Footprint and Biocapacity Accounts.
A framework for improvement
Nearly every human activity places some demand on biocapacity; therefore data is a critical need for robust accounts. The National Footprint and Biocapacity Accounts provide country level assessments. These accounts were deliberately built on standardized UN (or para-UN) data sets which themselves are based on reports from national statistics offices to the United Nations. Using only UN data sets is of course limiting, not least because they do not cover everything, but they are also more broadly accepted. Our particular accounting method and guidelines are published in open access publications, and key results are accessible, for instance, through a data platform. Results are accompanied by an indication of data quality.
However, data limitations still require the accounts to omit certain elements or make assumptions, all of which are limitations on the robustness of the results. Given the significance of resource security metrics like the Ecological Footprint accounts to humanity’s wellbeing, our framework is based on a clear research question, designed to provide comparable results across countries, and able to be upgraded by us or others if improved data is available. We are also building a new organization to be a neutral, robust provider of these National Footprint and Biocapacity Accounts.
With the relevance and popularity of the national accounts, current and emerging applications of Ecological Footprint accounting at the city, company, individual, and other levels continually yield improved data sources and sharpened methodologies. The criticisms and fresh perspectives that arise from these applications are an important input for further improvements.
Guidebook on limitations and criticisms
In addition to comments and answers we have offered on GreenBiz and PLOS in response to criticisms, we have written a comprehensive Limitations and Criticism Guidebook for Ecological Footprint practitioners and the users of its results. The guidebook highlights the main known limitations and criticisms of the method. It covers:
Should Ecological Footprint accounts be trusted?
Why Ecological Footprint accounts are needed
A short introduction to the underlying accounting principles
• Key results
• Indices versus accounts
• Comparison to other metrics of human demand on nature
• Complementary approaches
Strengths and limitations
How the robustness of the accounts is being improved
List of common questions and criticisms, including “Why not just focus on carbon?”