Green to Grey
Green to Grey is a cross-border, collaborative data project about Europe's disappearing nature.
Vital natural ecosystems in Europe are disappearing at an alarming rate to make way for housing, warehouses, golf courses and five star hotels. The legislation that exists to protect nature is failing. Every hectare lost compromises European health and security, and we are losing hectares much faster than we planned. Green to Grey quantifies how much nature is being lost to construction in Europe and sets out to qualify how these losses impact all of us.
We analysed a global land cover dataset produced by Google and the World Resource Institute using a deep learning image recognition model. The algorithm identified millions of natural or agricultural areas that were built on between 2018 and 2023. Then we verified more than 10,000 data points by hand to improve the model’s accuracy and calculate estimates with margin of error, a process that took more than 500 hours. To find relevant case studies, we matched the built-up areas with European and national datasets of valuable nature like forest and wetland, including areas protected under local, national or European legislation. Read our full methodology for more details.
The project was initiated by Arena for Journalism in Europe and the Norwegian public broadcaster NRK. The Norwegian Institute for Nature Research (NINA) provided scientific expertise for the project.
The idea was born in 2024 after the Arena team read NRK’s ground-breaking investigation into disappearing nature in Norway. We invited a group of journalists from across the continent to our Climate Arena conference in Bologna to discuss expanding the methodology to the whole of Europe. An eleven-country team assembled from some of the foremost newsrooms in Europe to begin work in January 2025. We published our findings in October 2025.
Coinciding with the launch of Green to Grey, the scientists that pioneered our methodology at NINA started a new participatory verification system for detecting artificial surfaces anywhere in the world. They are recruiting volunteers to act as citizen scientists in this exciting next phase.
Help NINA's scientists continue the project: Use the Nature Loss Detector App
Write to your MEP: Find your MEP
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