Democratizing Satellite Imagery: the Sentinel-2 Land Cover Explorer Map

In this map series, we partner with The Energy Mix, a leading energy transition publication based in Ottawa. Monthly, we unveil an interactive map that delves into climate change's causes and effects, enriched with insights from Canadian experts and spotlighting Indigenous and First Nations' narratives and solutions on climate change. Contact us to recommend a map!

Cairo, Natural Color Imagery

Cairo, Land Cover Distribution

Cairo, Moisture Index

Cairo, Short-Wave Infrared

Cairo, Vegetation Index

Cairo, Color Infrared

It shouldn’t come as a surprise that some of the most powerful tools in the fight against climate change come from the world’s leading mapping experts. With cutting-edge technology and vast resources, companies like Esri, alongside heavy-weight partners like Microsoft and Impact Observatory, are making bold strides. The Sentinel-2 Land Cover Explorer app allows users to visualize how landscapes have evolved over the past seven years, making it a crucial weapon in the battle to understand and combat the deep changes reshaping our planet.

In Canada alone, from exposing illegal mining activities to denouncing ecocide urban practices, these tools can empower conservation groups with new data and new arguments.

From data availability to accessibility

The Land Cover Explorer aggregates two critical sets of geospatial data.

First, comprehensive land cover data, derived from Sentinel-2 imagery with the help of AI, that offers a pixel-by-pixel classification of land into nine main types, including water, ice, built-up areas, forests, and cropland. This allows users to dynamically compare changes over time, measuring shifts in land cover for any chosen area.

Second, access to the Sentine-2 source imagery itself for interrogating and validating changes observed in the land cover.

The Georgia Straight and the City of Vancouver - click to see live scene 🔗

At the heart of this free resource is a mission of data democratization.

Robert Waterman, who has led satellite imagery efforts for the ArcGIS Living Atlas team at Esri for nearly a decade, emphasizes the importance of not just making data available, but also accessible. "Availability doesn't mean accessibility," Waterman explains. "Up until recently, this kind of data was only accessible to those with the hard skills, financial and computing resources required to process it." The Land Cover Explorer seeks to lower these barriers, empowering activists, governments, and everyday citizens to engage with vital environmental data. As Waterman puts it “[data] accessibility is availability + usability”.

Invaluable insights, within clicks

The value of this data in the fight against climate change is undeniable. The technology and resources required to collect regular, granular satellite imagery are beyond the reach of most, yet this data is crucial for analyzing and understanding the drivers of the climate crisis, its consequences, and its feedback loops.

The team behind the Land Cover Explorer isn't trying to deliver a predetermined narrative. Instead, they aim to provide a tool for discovery. "It's incumbent on the user," says Waterman, "to contextualize information and knowledge for decision-making." 

Taking this advice to heart, I explored the tool myself to test some widely held assumptions about climate change and the human impact on our planet. Within minutes, I was able to confirm several alarming trends (between 2018 & 2023)*:

• Rapid urbanization at the cost of natural habitats: Calgary saw a 5% increase in built-up areas over six years, in the context of the city approving housing developments near fragile wetlands (see animation below), while Lima experienced an 8% rise.

• Melting Glaciers: the Canadian Columbia Glacier and Silvethrone Caldera lost 8% and 6% of their snow and ice cover respectively

• Rampant deforestation: this zone of the Apui Region in the deep Amazon rainforest experienced a 6% decline in tree cover.

  
  

I was also able to track the expansion of large-scale fossil extraction projects worldwide. Unsurprisingly, and despite the urgent climate imperative to end extraction, some of the biggest open coal mines out there are still expanding: the Vista Mine in Canada saw a 20% increase in range land cover between 2018 and 2023, on extralegal expansion claims (see animation below), while the Raspadskaya Mine in Russia grew by 9% over the same period. These insights, once nearly impossible for the average person to obtain, are now just a few clicks away.

The Calgary Metropolitan area between 2017 & 2023 - click to see live scene 🔗

The Vista Coal Mine in Canada between 2018 & 2023 - click to see live scene 🔗

From accessibility to actionability

With all this data at our fingertips, the question remains: what do we do with it? While Land Cover Explorer bridges the gap between availability and accessibility, it doesn't necessarily address actionability. "These apps are a starting point. They demonstrate what's possible," says Waterman. "Users can expand on these building blocks to derive application specific insights in ArcGIS to facilitate decision-making."

"The task ahead is immense. We need to expand on these building blocks to develop smart tools that facilitate decision-making."

But there’s more data to make available first. The Land Cover Explorer app is only one tool in a growing suite of imagery explorer apps built by the Living Atlas team. The team recently introduced another powerful dataset through the Sentinel-1 Explorer app, which provides satellite imagery for any location on Earth. This new dataset offers renderings from SAR sensors that send and receive radar pulses that echo off the planet’s surface. This capability unlocks highly specific analysis use cases, such as enhanced monitoring of agriculture, flooding, and water pollution.

One significant advantage of these sensors is their ability to "see" beyond clouds and collect data without relying on sunlight. This capability allows for more real-time monitoring of the planet's surface, although data freshness was halved from 6 to 12 days when one of the two satellites of the mission ceased functioning in 2021.

The scene above shows New York City and surroundings through SAR sensors, during the heavy rainfalls of September 2023 - on the right, with a water index to denote water intensity and on the left, water anomaly that can detect oil, sewage or seaweed pollution (live scene🔗)

The Future of Satellite Imagery and AI

My conversation with Waterman wrapped up with a look at the future possibilities opened up by AI, which has helped make satellite imagery a hot topic in both industry and climate activism. "There's so much potential to enrich our immediate understanding of the Earth's surface," Waterman says. "Real-time object detection, tree counting, and more refined land cover analysis that respects local specificities are just the beginning."

The hope is that these advancements, when placed in the right hands, will enable us to keep destructive industrial practices in check, guide restoration efforts, and provide a clearer understanding of the damage already done and the challenges that lie ahead.

*Note that these findings are not to be taken without allowing for a margin of error. They’re the result of a high-level satellite imagery analysis of the general area in scope.