Open ocean & forest intelligence
Tidewatch puts coral heat stress, sea-surface temperature, sea level, protected areas, maritime zones and 25 years of tree-cover loss on one map. Click any place to get a cited, licence-aware brief built from NOAA, NASA, UNEP-WCMC, UMD and VLIZ data.
Reef stress: NOAA Coral Reef Watch, Oct. 20, 2026 · Mangroves: GMW v3 (2020) · Forest loss: GFW/UMD 2020–2024 · News: last 30 days · Imagery: NASA Blue Marble
The problem
Practitioners describe the same friction again and again: dozens of portals, inconsistent formats, unclear reuse terms, and maps that report protection coverage as if it were quality. Small teams without GIS staff lose days just assembling the basics for a site.
Tidewatch does not replace the datasets. It works as a navigator: it brings the authoritative layers into one view, shows the exact numbers at any point, and tells you where each number came from and what you may do with it.
Read the problem research“There are too many tools… We don’t need another tool.”
“Oftentimes, you’re dealing with piecemeal data…”
“Well, I hate to admit it, but I go to Google…”
A quarter of the coverage of the 100 largest MPAs is not yet implemented, and a third allows activities incompatible with conservation.
Who it’s for
“When did heat stress hit my reef, and how bad was it?”
Daily NOAA Coral Reef Watch sea-surface temperature, anomaly and Degree Heating Weeks for the 5 km pixel over your site, against the CRW alert levels. Print it as a site brief for a monitoring report.
Satellite SST matches loggers well at monthly scales but misses daily peaks, so pair it with in-water loggers (Bos & Pinsky, Coral Reefs 2025).
“How much is protected, and how well?”
WDPA sites with their IUCN category, status and no-take field as reported, the EEZ and its sovereign, and national MPA coverage against the 30×30 target, in a brief for a point or a whole EEZ.
Designation isn’t protection: about 8.4% of the ocean is in MPAs, but about 2.8% is fully or highly protected (Protected Planet Report 2024).
“What changed on the ground, and can we show funders?”
Year-by-year tree-cover loss since 2001, active fires and mangrove extent on one map. A site brief bundles the map, national trends and full citations, ready for a grant or donor report.
Tree-cover loss is not deforestation, and it can miss small clearings: in one area of small forest plots, only 11.1% of mapped forest-loss patches were detected (Yamada et al., Remote Sensing 2020).
“Is this number real, and can I republish it?”
Headlines from established newsrooms and science agencies, linked to the matching map layer. Every value in a brief carries its dataset, version, access date and licence.
Licences differ: the WDPA, for example, can’t be redistributed or used commercially without permission (UNEP-WCMC licence). Tidewatch shows it but never exports it.
What’s changing
The fourth global bleaching event (2023–2025) exposed ~84% of reef area to bleaching-level heat stress, across 83 countries and territories. Earlier events reached 21% (1998), 37% (2010) and 68% (2014–17).
Satellite heat stress predicts bleaching risk; it is not an observation of bleaching. Pair it with in-water surveys.
2024 saw 6.7 million hectares of tropical primary forest lost, 80% more than 2023, and 30 Mha of tree cover lost globally. Fires released an estimated 4.1 Gt of greenhouse-gas emissions.
Tree cover loss is not the same as deforestation: it includes fire, harvest and plantation rotation.
University of Maryland researchers mapped 36.6 Mha of forest disturbed by fire in 2023 and 38.3 Mha in 2024, the highest since monitoring began in 2001. Fire was 42% of all forest disturbance in those years, up from 26–29% in 2001–2019.
A thermal anomaly marks heat at the time of the overpass. It can be a wildfire, an agricultural burn or a gas flare.
Global Mangrove Watch maps ~147,000 km² of mangroves (2020). FAO estimates a net loss of 284,000 ha (2,840 km²) from 2000 to 2020. The leading drivers were aquaculture (26.7%) and natural retraction (25.9%).
Mangrove extent maps are about 25 m resolution. Narrow fringes and very recent change may be missed.
What you get
Click anywhere to get the EEZ, Large Marine Ecosystem, sea, protected areas, nearest tide gauges and 90-day coral heat stress, gathered in one panel.
Daily NOAA and NASA layers on a date slider. Tree-cover loss runs on a year-range slider (2001–2025), decoded in your browser so it updates instantly.
Up to 40 years of NOAA CRW SST, anomaly and Degree Heating Weeks at a 5 km pixel, and more than a century of monthly sea level at UHSLC gauges, with trends shown only when the record is long enough.
Every layer carries plain-language badges: Open, Attribution, View only, Non-commercial. Restricted data such as the WDPA is displayed live and never exported.
Each brief lists the exact datasets, versions and DOIs behind every number, ready to paste into a report or grant.
Download boundaries, briefs and time series as GeoJSON or CSV, with licence and citation metadata embedded. You can only export what you are allowed to share.
Data sources & credits
These entries come from the same catalog the map uses (GET /api/layers), so the licence you see here is the one the app enforces. Full notes are in DATA_SOURCES.md in the repository and on the methodology page.
Satellites flag risk. Surveys like this one at Rose Atoll confirm what actually happened.Methodology & how to cite
Tidewatch (2026). Tidewatch: an open map of ocean and forest change, v0.1. Toradle. Accessed 2026-10-22. Cite the underlying datasets listed in each place brief.
Search for a country, EEZ, sea, Large Marine Ecosystem or tide gauge, or just click the map.
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