Satellite images from US espionage programmes for ecology and nature conservation

The images taken by US spy satellites since the late 1950s have long been classified. They became publicly accessible in the late 1990s and are used, among others, in climate research and archaeology.

Researchers from the Conservation Biogeography Lab of the Institute of Geography at Humboldt-Universität led by Tobias Kümmerle also take interest in the black-and-white photographs. They provide a detailed look into the planet’s recent past. "What is unique about the images from the spy satellites is that they depict a large part of the Earth’s surface in high resolution, at a time from which little or no image material was previously available for most regions. This allows us to look back to a time when many environmental changes, such as the destruction of tropical forests, had simply not yet happened," says Kümmerle. The historical satellite images are so detailed that individual trees can be recognised with the naked eye. To analyse the images, the researchers use software that was originally developed for working with drone images.

Better understanding of yesterday’s environmental changes helps to improve nature conservation

Together with geographer Catalina Munteanu, who worked in Kümmerle’s team until 2021 and is now a researcher at the University of Freiburg, he wants to advance the use of historical remote sensing data. In a recent study, the researchers show that more than one million images from four historical US espionage missions are waiting to be analysed. The study also provides an overview of ecological research that is already utilising historical satellite images. The aim is to better understand environmental changes in the past to define meaningful goals for nature conservation today and recognise threats at an early stage.

EcoSpy project

Initial studies were carried out at the HU between 2018 and 2020 as part of the EcoSpy project. Catalina Munteanu analysed a series of images taken by the US Corona spy satellites between 1960 and 1972. Among other things, Munteanu investigated which forests remained untouched in the Romanian Carpathians during this period. "With the spy satellite images, we can better localise where near-natural forests are actually located and how we can protect them," explains Catalina Munteanu.

Publication

Research article: "The potential of historical spy-satellite imagery to support research in ecology and conservation"