- Global Earth Observation 2026
- Chapter 8
Systems in depth
One section per system: its state at evidence close, its exposures and what the operational series will watch.
Contents
- ·Edition home
- ·Executive summary
- 1Observation is where evidence begins
- 2Key findings
- 3Systems and sectors at baseline
- 4Risks and capability
- 5Observation gap under an extreme season
- 6Readings from the other desks
- 7The 2027 agenda
- 8Systems in depth
- AMethodology
- BData appendix
- CReferences and record
- ·Complete edition, for print
8.1Earth observation and water
Water is observed from space and from the ground. Surface extent, rainfall, snow, ice, ocean heat and sea level are tracked as long records, and the records are only as good as the missions that carry them.
| Component | State | Evidence | Status |
|---|---|---|---|
| Surface water | three million Landsat images mapped change at 30 m over 32 years | 33 | Reported |
| Sea level and ocean heat | sea level 4.75 mm a year; ocean heat at a 66-year high in 2025 | 3 | Reported |
| Glaciers | mass loss in 2024 and 2025 among the five most negative on record | 3 | Reported |
| Water use | volumes of water use by sector are not bound here | 16 | Expert input |
Couplings
- EO → WAT surface and ocean records
- WAT → FOO soil moisture and irrigation
- WAT → BIO surface extent
Evidence to bind in 2027
- water use volumes by sector
- in situ gauge coverage by region
Related editions
- GLB Global Systems
- GS-01 Water
- GS-03 Food and Agrifood Systems
- GS-04 Health and One Health
- GS-07 Climate and Earth Systems
- GS-11 Biodiversity and Ecosystems
8.2Earth observation and food
Food security monitoring uses satellite vegetation and rainfall data with partner assessments. The consensus method has run monthly for crops at risk since 2016.
| Component | State | Evidence | Status |
|---|---|---|---|
| Crop condition reports | monthly consensus for countries at risk of food insecurity | 21 | Reported |
| Open archives | Landsat and Sentinel archives feed crop and land products | 109 | Reported |
| Small farms | coverage of small fields and yield accuracy are not bound here | 21 | Expert input |
| Forests and food | cropland expansion enters forest loss records | 5 | Inferred |
Couplings
- EO → FOO crop condition
- WAT → FOO soil moisture
- FOO → BIO cropland expansion
Evidence to bind in 2027
- yield accuracy on small fields
- price transmission from crop reports
Related editions
- GLB Global Systems
- GS-01 Water
- GS-03 Food and Agrifood Systems
- GS-04 Health and One Health
- GS-07 Climate and Earth Systems
- GS-11 Biodiversity and Ecosystems
8.3Earth observation and health
Early warning, heat exposure and air quality monitoring depend on observation, models and delivery. Coverage is rising, and the gap between countries with and without comprehensive systems is large.
| Component | State | Evidence | Status |
|---|---|---|---|
| Early warning | 119 countries, 60% of all; small island developing States 43% | 2 | Reported |
| Comprehensiveness | mortality nearly six times lower where systems are more comprehensive | 2 | Reported |
| Heat | an average of 546,000 heat-related deaths a year; 16 attributable days of dangerous heat per person in 2024 | 34 | Reported |
| Air quality | satellite-based exposure series not bound here | 34 | Expert input |
Couplings
- EO → HLT heat and hazard warning
- WAT → HLT flood and disease risk
- BIO → HLT smoke exposure
Evidence to bind in 2027
- warning reach to the most exposed people
- satellite-based exposure series
Related editions
- GLB Global Systems
- GS-01 Water
- GS-03 Food and Agrifood Systems
- GS-04 Health and One Health
- GS-07 Climate and Earth Systems
- GS-11 Biodiversity and Ecosystems
8.4Earth observation and nature
Forests, surface water and methane sources are observed from space. Satellite-based records show where loss slowed in 2025 and where fire raised it.
| Component | State | Evidence | Status |
|---|---|---|---|
| Forest extent | 4.14 billion hectares, 32% of land; net loss 4.12 million hectares a year in 2015 to 2025 | 6 | Reported |
| Tree cover loss | tropical primary forest loss fell 36% in 2025 after a record fire year | 5 | Reported |
| Long record | 2.3 million km2 lost and 0.8 million km2 gained in 2000 to 2012 | 32 | Reported |
| Methane | a dedicated satellite lost contact on 20 June 2025 | 23 | Reported |
Couplings
- EO → BIO forest and surface mapping
- FOO → BIO cropland expansion
- EO → CLI methane and carbon records
Evidence to bind in 2027
- methane detection coverage after 2025
- biodiversity beyond forest cover
Related editions
- GLB Global Systems
- GS-01 Water
- GS-03 Food and Agrifood Systems
- GS-04 Health and One Health
- GS-07 Climate and Earth Systems
- GS-11 Biodiversity and Ecosystems
8.5Observation continuity, security and extremes
The observing system has three exposed channels: ageing sensors, thin ground networks and crowded orbits. The 2025 and 2026 evidence shows each of them.
| Component | State | Evidence | Status |
|---|---|---|---|
| Ageing flagships | Terra, Aqua and Aura end of science projected Feb 2027, Sep 2027 and Aug 2028 | 12 | Reported |
| Programme funding | FY2026 request restructured Landsat Next with no funding for it | 11 | Reported |
| Ground networks | in situ observations deficient over parts of Africa, South America, Southeast Asia, deep ocean and polar regions | 1617 | Reported |
| Orbits | about 1,200 intact objects re-entered in 2025 | 1 | Reported |
Couplings
- INF → EO record continuity
- DAT → HLT in situ gaps
- AIC → EO model dependence
Evidence to bind in 2027
- funding outcomes after evidence close
- ground segment resilience
Related editions
- GLB Global Systems
- GS-01 Water
- GS-03 Food and Agrifood Systems
- GS-04 Health and One Health
- GS-07 Climate and Earth Systems
- GS-11 Biodiversity and Ecosystems
Notes
Numbers are the edition’s reference numbers, so a note reads the same in every chapter. The full list, with every source and its licence, is in Annex C. Annex C, references
- 3WMO (ed.), State of the Global Climate 2025, one-page summary of the report released 23 March 2026. World Meteorological Organization, Geneva. Observation year 2025 (greenhouse gases 2024). Accessed 2026-11-03.back
- 33Pekel, J.-F. et al., High-resolution mapping of global surface water and its long-term changes, Nature 540, 418 to 422, 2016. Springer Nature, London. Observation year 2015 (study period 1984 to 2015). Accessed 2026-11-03.back
- 16GCOS (ed.), The 2022 GCOS Implementation Plan (GCOS-244), abstract and summary of themes, as held in the AWI EPIC repository (the full plan was not opened). World Meteorological Organization, Geneva. Observation year 2022. Accessed 2026-11-03.back
- 21NASA Harvest (ed.), GEOGLAM Crop Monitor for Early Warning Releases 100th Issue, 5 December 2024. NASA Harvest, College Park. Observation year 2024. Accessed 2026-11-03.back
- 10USGS National Land Imaging Program (ed.), NLI Update to the National Geospatial Advisory Committee, March and April 2026 (fiscal year 2025 archive statistics; Landsat 8 and 9 status). US Geological Survey, Reston. Observation year 2025. Accessed 2026-11-03.back
- 9Copernicus Data Space Ecosystem (ed.), Annual Report 2024. European Space Agency and consortium partners, Paris. Observation year 2024. Accessed 2026-11-03.back
- 5World Resources Institute and Global Forest Watch (eds.), Global Forest Watch’s 2025 Tree Cover Loss Data Explained (with University of Maryland GLAD tree cover loss data and comparison with JRC and PRODES series). WRI, Washington. Observation year 2025. Accessed 2026-11-03.back
- 2UNDRR and WMO (eds.), Global Status of Multi-Hazard Early Warning Systems 2025, as reported in the WMO press release of 12 November 2025, Early warning systems reach new heights, but critical gaps jeopardise global progress (the report itself was not opened). World Meteorological Organization, Geneva. Observation year 2025. Accessed 2026-11-03.back
- 34WHO (ed.), Climate inaction is claiming millions of lives every year, warns new Lancet Countdown report, news release of 29 October 2025. World Health Organization, Geneva. Observation year 2024 (deaths averaged over the series period). Accessed 2026-11-03.back
- 6FAO (ed.), Global deforestation slows, but forests remain under pressure, FAO report shows, release on the Global Forest Resources Assessment 2025, 21 October 2025. Food and Agriculture Organization of the United Nations, Rome. Observation year 2025. Accessed 2026-11-03.back
- 32Hansen, M.C. et al., High-Resolution Global Maps of 21st-Century Forest Cover Change, Science 342(6160), 850 to 853, 2013 (journal record and summary opened). American Association for the Advancement of Science. Observation year 2012 (study period 2000 to 2012). Accessed 2026-11-03.back
- 23Environmental Defense Fund and MethaneSAT (eds.), MethaneSAT loses contact with satellite, project update of 1 July 2025. Environmental Defense Fund, New York. Observation year 2025. Accessed 2026-11-03.back
- 12NASA (ed.), Terra: The End of an Era (with end-of-science projections for Terra, Aqua and Aura). National Aeronautics and Space Administration, Washington. Observation year 2026. Accessed 2026-11-03.back
- 1ESA Space Debris Office (ed.), ESA’s Annual Space Environment Report, issue 10.0, 1 May 2026. European Space Agency, ESOC, Darmstadt. Observation year 2025 (modelled population at reference epoch August 2024). Accessed 2026-11-03.back
- 11Congressional Research Service (ed.), Landsat, What’s Next? In Focus IN12281, updated 16 June 2025. Congressional Research Service, Washington. Observation year 2025 (FY2026 request). Accessed 2026-11-03.back
- 17WMO (ed.), Closing the gaps in the observing network (news article on the Global Basic Observing Network and the Systematic Observations Financing Facility). World Meteorological Organization, Geneva. Observation year not stated on the page. Accessed 2026-11-03.back