Country Overshoot Day Calendar – Explaining the Changes

Changes in the Dutch Ecological Footprint, to take this country as an example, in the Latest National Footprint and Biocapacity Accounts

Introduction

The Dutch Ecological Footprint results for the latest edition of the National Footprint and Biocapacity Accounts (2025 Edition released in April 2025) differ significantly from the prior edition. Also, these changes in the Netherlands’ estimated Ecological Footprint  have been far more pronounced than for most other countries. As a consequence, the historical Dutch Overshoot Days have shifted, raising questions about the reasons for this shift, and the robustness of the results. underlying factors driving this adjustment.

This webpage examines the key reasons and factors that have led to this changes. In summary, the most influential driver behind this change was the restructuring of carbon embodied in trade data as explained below. In the following, we present more details how these accounting improvements have impacted the Dutch Ecological Footprint calculations and the results they create.

Key Factors Driving the Change in Results

1. Changes in Carbon Embodied in Trade

One of the primary updates in the 2025 edition involves changes in how carbon embodied in trade is accounted for. These changes stem from a restructuring of commodity classifications within the UN Comtrade data source, a key international dataset for trade statistics.

• Previous Methodology:
  • In prior editions, trade data was consolidated under a single classification system: Standard International Trade Classification (SITC 1).
  • This meant that all commodities were categorized under a single standardized system, simplifying calculations of carbon embodied in trade.

• New Methodology (2025 Edition):
  • The UN Comtrade update restructured trade data, dispersing it across four different SITCs instead of one.
  • To align with these changes, the National Footprint and Biocapacity Accounts team converted the data back into a unified SITC 1 format using expanded datasets and guidance from UN Comtrade.
  • This adjustment introduced changes in how carbon emissions associated with traded goods are calculated, impacting the Ecological Footprint of multiple countries, including the Netherlands.
  • Note: One of the reasons the recent change in Footprint is large is that previously Netherlands was a net importer of embodied CO2 emissions, while the newer data shows Netherlands as a net exporter of embodied CO2 emissions. This may initially seem unusual, however it is to be expected that the composition of commodities that a country imports would be different than what it exports. And therefore taking into account the flows in more detail likely affects the sum of each trade flow differently.

2. Impact on Dutch Carbon Footprint Calculations

A major effect of this reclassification has been the re-evaluation of CO2 emissions embedded in Dutch imports and exports. The updated methodology reveals that:

• Both imported and exported CO2 emissions are now estimated to be significantly larger than in previous editions.
• The increase in CO2 emissions embedded in exports was greater than the increase in CO2 emissions embedded in imports.
• Since the Dutch EF is calculated as domestic consumption (production + imports – exports), the higher estimate of exported emissions means that more CO2 is attributed to other countries, reducing the Dutch consumption-based Ecological Footprint.
• Given the Netherlands’ large trade flows, even small methodological changes can have a substantial effect on the country’s overall Ecological Footprint calculation.

3. Latest Data Comparison

To illustrate the scale of these shifts, the latest 2025 edition data shows for 2023:

• Carbon Footprint (production): ~40 million global hectares (gha)
• Carbon Footprint of Imports: ~154 million gha
• Carbon Footprint of Exports: ~158 million gha

The high trade volume means that even moderate shifts in how embodied carbon is calculated can significantly impact the Dutch Ecological Footprint and with it its Overshoot Day.

4. Trends in Per Capita Ecological Footprint

While methodological adjustments drive the absolute changes in the Dutch Ecological Footprint, there is also a noticeable trend in the per capita Ecological Footprint in the newer dataset.

• The updated data suggests that the Netherlands’ per capita Ecological Footprint has been decreasing more steeply since the early 2000s than previously estimated.
• A comparison between the 2023 edition (grey data) and the preliminary 2025 edition (orange data) indicates that the revised methodology aligns more closely with a declining per capita Ecological Footprint trend.
• This suggests that past editions may have overestimated Dutch per capita Ecological Footprint, and the new calculations better reflect actual reductions in environmental impact per person.

Figure 1: This graph shows the average per person consumption Ecological Footprint in the Netherlands. The newer edition (the preliminary 2025 edition, in orange) shows a decreasing trend in per capita Ecological Footprint, more than the 2023 edition (in grey). The difference is particularly marked since 2010.

Conclusion

The revised National Footprint and Biocapacity Accounts (2025 Edition) has introduced important methodological changes, particularly in how carbon emissions in trade are classified and accounted for. These adjustments have led to:

• Higher estimates of carbon embodied in imports and exports
• A greater increase in exported emissions than imported emissions, leading to a lower Dutch consumption-based Ecological Footprint
• A steeper decline in per capita Ecological Footprint since the early 2000s, as shown in the latest dataset

While accounting changes are often technical in nature, they are essential for ensuring that Ecological Footprint calculations accurately reflect the latest trade and emissions data. In the case of the Netherlands, these updates provide a clearer picture of the country’s resource consumption and trade dynamics, reinforcing the need for continuous improvements in environmental accounting methods.

Why historical Country Overshoot Days are not Published

Each year, the National Footprint and Biocapacity Accounts are updated, not only with the newest data, but also with other refinements, primarily improved historical datasets. As a result, historical timelines shift slightly, which in turn affects past Overshoot Day calculations.

Like GDP estimates, these accounts are not perfectly precise and are refined with each new edition. Every year, the entire dataset is updated back to 1961. Even small adjustments can shift Overshoot Days by a few days, which may seem confusing to those unfamiliar with the accounts’ methodology. However, such shifts are inevitable. It’s worth noting that a single day in a 365-day year represents just 1/3 of a percent, so even minor changes in the data can alter dates.

For this reason, we do not publish Country Overshoot Day timelines. Instead, we recommend visiting https://data.footprintnetwork.org to explore the full time series for each country.

Additional Resources

Country Deficit Day
Country data on Footprint Data Platform
Earth Overshoot Day
About the Ecological Footprint
About Country Overshoot Days
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