The Occasional Observer

...peat fires are a recurring (2004, '06) phenomenon in Indonesia.

And not a natural phenomenon, for the most part. Most of the fires are man-made; slash and burn techniques are used to clear forests, and the forest fires in turn ignite the peat, which smolders like a burning cigarette. The Indonesian government has contributed to the problem by trying to drain some of the peat bogs for conversion to agriculture.

But here's the mind-blowing part:

[It is] estimated that during 1997 and 1998 smouldering peat beneath the Borneo forests released between 0.8 and 2.6 billion tonnes of carbon into the atmosphere. That is equivalent to 13 to 40 per cent of all [global] emissions from burning fossil fuels, and contributed to the CO2 peak in 1998. [emphasis added]

Peat fires are a two edged sword. A natural peat bog is actually a carbon sink, so its destruction not only releases the sequestered carbon to the atmosphere, it reduces the earth's capacity to regulate the carbon balance.