Satellite Earth observations (EO) are
unique in their ability to provide consistent and
comparable information on global land cover. Imagery
may be used to measure the extent of land cover
types and their change over time. This is
complemented by radar imagers that can provide
further information on vegetation type, soil
moisture and biomass and can measure day-and-night,
in all weather conditions, and ‘through’ some forest
canopies.
Satellite EO is a fundamental
tool for deriving statistics on deforestation and
land use change and is critical to monitoring the
Indicators of SDG Targets 15.2, 15.3 and 15.b from
local to national, regional and even global scales –
in some cases allowing the assessment of trends over
long historical archives.
Land degradation
Land degradation is a process of change
over time in vegetation cover, water resources, soil
erosion and salinity. Time series of coarse to
moderate resolution EO data can be applied globally
to reveal environmental changes and target hot
spots, and is used by national, state, and municipal
governments to manage their land use. Standardised
methods are being developed to allow consistent
derivation of three sub-Indicators for Indicator
15.3.1:
- land cover and land cover
change (see ESA Landcover CCI);
- land
productivity; and,
- carbon stocks above
and below ground.
The UN Convention to
Combat Desertification (UNCCD) commissioned a series
of Good Practice Guidance reports to help countries
select, process and analyse datasets to report
against these sub-Indicators, with EO closely
integrated into the recommended methods.
Forests
At the global level, FAO has been
carrying out its Forest Resources Assessments (FRA)
at 5–10 year intervals since 1946. From 1990,
information collected through country reporting has
been complemented by remotely-sensed data, supported
by a growing archive of satellite imagery and new
software for image processing and interpretation.
The World Resources Institute’s Global
Forest Watch (GFW) uses wall-to-wall national
coverage satellite EO data (Landsat) to provide
spatially explicit information at the pixel level
(30m). Information is presented via an online forest
monitoring and alert system empowering forest
management stakeholders to create custom maps,
analyse forest trends, subscribe to alerts or
download data for their local area or the entire
world.
The REDD+ initiative of the UN
Framework Convention on Climate Change (UNFCCC)
looks to provide financial incentives for countries
to maintain and sustain forests in an effort to
reduce emissions from deforestation and forest
degradation, foster conservation and management of
forests, and enhance forest carbon stocks.
In support of REDD+, the Global Forest
Observations Initiative (GFOI) aims to guarantee
availability of wall-to-wall national coverages of
satellite data and to provide countries with Methods
and Guidance Documentation (MGD) that will
facilitate reporting consistent with the relevant
IPCC Good Practice Guidelines. GFOI’s MGD advice is
available in English, Spanish and French
(www.gfoi.org/methods-guidance/) and via a new
online tool – REDDCompass – that guides users
through the core themes, concepts and actions
involved in the development of National Forest
Monitoring Systems.
