Fires add fuel to a warming planet
Australia's CSIRO is joining an international study using satellites to monitor the contribution fires make to global warming - both in greenhouse gas emissions and the destruction of trees that soak up carbon dioxide.
The project, named World Fire Web, involves scientists from 16 countries. It is being coordinated by the European Commission's Global Vegetation Monitoring Unit (GVM) in Ispra, Italy. Each participating country is responsible for monitoring a particular area and the results are then shared over the Internet to produce daily global fire maps.
According to Dr Dean Graetz of CSIRO's Earth Observation Centre, "fires make a significant contribution to the greenhouse effect - perhaps accounting for 40 percent of annual global greenhouse gas emissions". But, he says, "unlike fossil fuel emissions, we know comparatively little about where fires are occurring and how much carbon they are releasing".
CSIRO's Earth Observation Centre has been charged with tracking fires throughout Australia, New Guinea and parts of Indonesia. But in terms of fires this region is not at the top of the list. "Africa is the burning continent," says Dr Graetz, "followed by South America, Southeast Asia and Australia."
CSIRO has had an additional task in the project - to help correlate what is seen in satellite images with what is actually happening on the ground. "The satellite images used in the project are continuously processed, most semi-automatically by computers, to detect 'hot spots', or probable locations of current fires," says Dr Graetz. "But the most difficult task, not just for us, but for all of the project, is to train the computer to automatically recognize and measure burnt areas, while ignoring cloud shadows and other distractions," says Dr Graetz.
To help 'train' computers to measure the burnt areas, Dr Graetz and colleagues from CSIRO and the GVM have spent the last few months studying fires in the Northern Territory's Kakadu National Park.
Currently, the World Fire Web network covers two thirds of the globe, but the scientists plan to expand it by the end of this year to provide an almost global coverage of fires.