Indonesia — We have just returned from a wonderful trip to Australia where we visited relations’ new babies and friends.
We were there during the big dust storm, which reminded one graphically of the power of nature. Thousands of tonnes of soil have been removed from the Murray-Darling basin and redistributed around Australia, the Tasman Sea and New Zealand, not unlike the Dust Bowl of the American mid-west in the early 1900s.
Our friends have just bought a new house and they are coping with many deposits and charges relating to fire hazards. Australia is not quite the utopia we sometimes like to believe. Last year devastating bushfires in South Australia killed over 180 people and razed about 400,000 hectares of land. This year’s forecast is for an even hotter and drier summer and a consequent greater fire risk. I hope the forecast is wrong!
The immediate effects of large-scale fires either in Australia or California are obvious: loss of life, property and devastation of flora and fauna; whole lifetimes of investment on farms or businesses lost in one roaring belt of flame. Apart from these obvious and immediate effects, frequent or long-term fires can have a major effect on climate by producing greatly increased amounts of atmospheric carbon dioxide.
In Indonesia, there were major fires in 1997-8 which had the obvious devastating effects, but 10 years on, the problem of frequent and long-term fires, in the peat swamps of the area, is increasing rather that decreasing. They are usually caused by greed and illegal human activity. Peat is made up of compressed vegetable matter, usually in peat bogs, where the water aids compression. Peat is dug while wet and stacked to dry after which it provides a long, slow-burning fuel. The high carbon content of peat means that peat fires release vast amounts of smoke and carbon. Tropical peat swamp fires emit 300Mg (a mega-gram is 1,000,000g) of carbon a hectare. That compares with 7.5-10MgC/ha from other habitats.
In El Nino years, the carbon release can equal 40 per cent of the mean annual global carbon emissions, making it responsible for the biggest single annual increase in atmospheric carbon dioxide since records began. Between 2000-06, the Borneo peat swamp fires alone produced an average of 74Mtonnes of carbon a year. This makes Indonesia one of the world’s biggest carbon dioxide emitters.
These peat swamp fires are generally caused by illegal land clearing, use of fire as a weapon in land tenure disputes, use of fire for resource extraction or accidental fires. A major concern is that is the positive feedback caused by tropical forest fires burning increases the forest or peat swamp susceptibility to fire. Fire does not normally spread when the canopy is close and complete but after fires there are gaps in the canopy. This increases drying and therefore more fuel. The gaps then allow more wind in to fan the flames.
Peat swamp fires have special characteristics, the most obvious being their slow burning. Estimates of economic cost vary but the “slash and burn” policy has been said to have cost Indonesia US$20.1 billion (NZ27b). Clearly one of the most significant effects is on global warming. If Indonesia could eliminate the peat swamp fires, it would reach its Kyoto target in one move.