Severity of
Desertification on World Stage
(15 June 2007) Desertification puts
the health and well-being of more than 1.2 billion people in more than 100
countries at risk, according to the United Nations.
The theme of
this year's World Day to Combat Desertification, held every year on 17 June, is
'Desertification and Climate Change - One Global Challenge'.
According
to the United Nations Convention to Combat Desertification (UNCCD),
desertification is a process of land degradation that is partly due to
human-induced activities. With their view from space, satellites can track
land-use changes that often drive desertification - such as over-cultivation,
ill-managed irrigation and deforestation.
As stated by the Secretary
General of the UN Ban Ki-moon, "The theme of this year's World Day to Combat
Desertification and Drought … reminds us that climate change and
desertification interact with each other at a variety of levels. They are two
major manifestations of the same problem.
"On this World Day, let us
strive to address desertification and climate change in a synergetic fashion,
as part of an integrated approach to achieving sustainable development for
all."
Desertification does not so much refer to the spread of existing
deserts as the creation of new ones, through the reduction of productivity of
vulnerable dryland areas by soil deterioration and erosion as well as the
long-term loss of natural vegetation.
A spatial modelling tool has been developed in DesertWatch to simulate scenarios of desertification (named ScenDes). The tool generates possible scenarios for desertification monitoring, starting with a land use map at a certain time and simulating the land use evolution during the years. The simulation is typically carried out on periods of 10-20 years and allows to visualise possible land use degradation scenarios. These land uses can then be translated into desertification indicators. (courtesy: Research Institute for Knowledge Systems (RIKS))
Because dryland desertification can be
remedied or even reversed by using appropriate land management techniques,
monitoring and forecasting areas most at risk are essential. As well as
highlighting any relevant land use change, the view from space can support
authorities in getting an overall picture of key pressures on land, such as
burned land due to forest fires, erosion processes and their trends over time.
This information, together with climatic data and socio-economic information
provides an overview of the main causes and effects of land
degradation.
ESA has been working closely with the UNCCD secretariat for
more than five years to develop user-tailored and standardised information
services based on satellite observations to assess and monitor desertification
and its trends over time.
In 2004, ESA launched a satellite-based
information service called DesertWatch to work with three of the European
countries most affected by desertification - Italy, Portugal and Turkey. In
addition to helping national and regional authorities to assess and monitor
land degradation and desertification, DesertWatch also aims to support these
authorities in reporting to the UNCCD.
To this end, satellite
observations have been combined with in-situ information, processing tools,
numerical models and geo-information systems to create standardised and
comparable geo-information products that can be used to satisfy UNCCD reporting
requirements.
The Land Degradation Index (LDI) exploits remote sensing images, in conjunction with climatic and physiographic parametres, for assessing the landscape status with respect to its natural resources potential. Homogeneous land systems are identified and their status is expressed in terms of number of standard deviations from the population mean. The final values are then converted into 3 broad classes that indicate overgrown, normal and undergrown vegetation. (courtesy: Estación Experimental de Zonas Áridas (EEZA) from Consejo Superior de Investigaciones Científicas (CSIC), Spain)
The DesertWatch project is now close to
completing its second phase, during which a full operational system has been
developed by an international consortium. The DesertWatch information system
will provide key public administrations with a large number of indicators and
geo-information products relevant to monitoring and assessing the status of
land degradation.
The ultimate objective of DesertWatch is to install
software tools in the main operational centres of participating countries to
help national and local authorities to complete and improve their assessment on
land degradation and facilitate their decision making process in their fight to
combat desertification.
The Eighth Session of the Conference of the
Parties (COP 8) of UNCCD will be held in Madrid, Spain, from 3 to 14 September.
The COP is the main decision making group of the UNCCD, which meets regularly
to further the Convention's objectives.
ESA will host a side event
throughout the UNCCD COP entitled 'Earth Observation Technology to support the
UNCCD: the DesertWatch project'. DesertWatch is taking place as part of ESA's
EO Data User Element (DUE).
(source: ESA)