Tracking Africa's fires
Lynne Smit
When early human ancestors learned to control lightning strikes, fire heralded a major advance. Thousands of years later, our fascination with fire has not flickered and
gone out: the most sophisticated of new satellite technologies are being used to
study the impact of fire across the world.
Over 30% of the world suffers from the kind of widespread fires that have
critical regional implications. But according to geography professor Emilio
Chuvieco of Alcalá University in Madrid, Spain, only one country, in Africa has
a fire damage assessment system - South Africa.
Chuvieco told delegates at the International GeoScience and Remote Sensing
Symposium (IGARSS) held in South Africa that the lack of fire
damage assessments was particularly alarming in view of the fact that a large
part of Central Africa suffers from significant fire outbreaks with major
effects on ecosystems and human infrastructure.
“It is important to learn more about fires in Africa,” said geographer Gareth
Roberts of Kings College in London, UK.
“Climate change assessments look at the level of carbon emissions, but it has
not been easy to quantify biomass (biological material) burning,'' said Dr
Roberts who specialises in thermal sensing by instruments on weather satellites
such as those launched by the European Organisation for the Exploitation of
Meteorological Satellites (Eumetsat)
''This has led to a great deal of uncertainty about what is actually
happening in Africa.”
Roberts has been analysing data produced by geostationary satellites, which
appear motionless in the sky because they orbit at the same rate at the planet,
to study fires in Africa.
“Fire produces radiative power, and this can be used to calculate how much
fuel is being consumed,” he said.
“Most of the fires in Africa are low intensity, small fires but together they
are responsible for pretty high emissions,” he said. “The study has
also shown the pattern of fires, in which seasons and at which time of day they
are most common.”
Africa differs to anywhere else in the world because most of the carbon
emissions - implicated in global warming - caused by fire actually come from
small, low intensity burns.
The use of fire is woven into the daily life of many people in Africa, not
just for cooking and keeping warm in winter but also as an integral part of
agriculture.
Unlike other continents where fires are more common in sparsely populated
areas, in Africa the rule is that the higher the density of people, the more
fires occur, he said.
Ecologist Sally Archibald from the Council for Scientific and Industrial
Research (CSIR) has been using satellite data coupled with field work to study
fires in and around the Kruger Park.
“It is important to identify fires,” she agreed. “This research can be used
to characterise ecosystems – different vegetation burns with different
intensity. Combined with weather data, the knowledge we are gaining can help to
predict fires. We are also finding out valuable information about the factors
that inhibit fire spread.”
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