Global Mangrove Watch 4.1 Launch

From Forensics to Action: The Evolution of GMW

Lammert Hilarides, Wetlands International

Lagune de la Somone, Senegal

For years, tracking global mangrove loss has felt a bit like performing historical forensics. When early versions of the Global Mangrove Watch (GMW) platform launched, we were looking at broad, retrospective snapshots of the world's coastlines. We could see where mangroves had been, but by the time the maps were published, the loggers had moved on, the shrimp ponds were built, or the restoration planting had already succeeded or failed on the ground. Data was treated as a finished monument, built by scientists, published in journals, and left static until the next major funding cycle.

With the release of the GMW 4.1 dataset and our latest batch of platform updates, that era is officially over.

We are introducing a continuous, unbroken annual time-series stretching from 1985 all the way to 2025, complemented by near real-time monthly alerts of mangrove loss until June 2026.

Aerial photograph from Senegal 2023 taken during GMW training.

"This update isn't just a deeper archive or a minor technical patch. It represents a fundamental shift in how the Global Mangrove Alliance operates: moving away from treating data as a static scientific product, and embracing it as an active, living operational framework driven by people who use it for conservation and restoration on the ground." Lammert Hilarides, Wetlands International

Our journey since publishing version 2.0, the first publicly available version, in 2018 has taught us that data is only as good as its responsiveness to reality. Science shouldn't happen in a vacuum. By listening to feedback from hundreds of people over many years, whether through formal website channels or informal feedback during trainings, we have deliberately evolved GMW into a tool built for real-world application.

New features and updates

The GMW version 4.1 dataset provides a new foundation for our work by providing the most stable, reliable time series of mangrove extent and change yet.

The dataset now accurately separates gross loss and gross gain into individually usable layers. Instead of looking at a "net change" figure that hides massive local clear-cutting behind a wall of natural growth elsewhere, practitioners can now isolate exactly where destruction is happening versus where recovery is taking root. When you combine this deep historical backdrop with our monthly mangrove loss alerts, which now feature a temporal visualization color-coded by the recency of the alert, local teams can immediately spot and react to illegal clearing as it happens.

Users can now distinguish exactly where mangroves are being lost versus where recovery is taking root. 

To support making this data truly actionable, the platform itself has undergone a transformation. For the first time, we are introducing much requested features of user accounts, subscriptions, and customizable areas of interest. Users no longer have to navigate from the global map from scratch every time they visit but instead can now draw a boundary around their own areas of interest, revisit those and receive tailored updates when new data comes in.

This localized, user-driven approach is already changing how stakeholders manage their mangrove forests. Take Ecuador, where the national GMA Chapter is building its very own national mangrove monitoring system based on GMW data and empowering local stakeholders to directly track and defend their forests. Similarly, in Kenya, the Kenya Forest Service is utilizing these tailored insights to make an immediate difference in how regional marine resources are governed and restored.

To bridge the gap between data and direct action even further, the platform now features a much closer integration with the Mangrove Restoration Tracker Tool (MRTT). Rather than just viewing loss from a distance, practitioners can now seamlessly transition from monitoring a site to tracking the actual progress and health of restoration projects over time.

The monthly mangrove loss alerts are now enhanced with color-coded visualizations, showing the recency of each alert. Local teams can immediately spot and react to potential illegal clearing as it happens. 

Crucially, version 4.1 acts as a rock-solid foundation for an entire ecosystem of derived datasets. While today we launch the update to GMW extent and change data, it paves the way for a complete refresh of our most critical diagnostic layers. Over the next twelve months, updates will roll out for our global datasets on mangrove biomass, blue carbon stocks, restoration potential and many others.

The Global Mangrove Alliance was founded on the idea that no single organization can protect the world's coastlines alone. By turning our scientific data into an open, community-driven process, we are ensuring that the tools to defend these vital ecosystems belong to everyone. The maps are sharper, the alert system is live, and the infrastructure is ready. We invite conservationists, policymakers, and researchers to create an account, subscribe to your regions of interest, and help us refine this platform even further by sharing your feedback through the GMW contact form, via email or by flagging data issues directly on GitHub.

The latest data is in your hands. Now, let’s continue to use it to make measurable differences on the ground. And we will measure them!