Op-€d the other press cience Matters — ossil fuels not the only culprit in climate change LUC ESUZUKI Most everyone has now heard about how burning fossil els like oil, coal and gas contributes to global warming. But human beings are also responsible for another, sig- ificant, contribution of greenhouse gases to the atmos- phere—wildfires. In 1997, more carbon dioxide (the principal green- Ouse gas) was pumped into atmosphere than during any bther year in recorded history. Certainly, we were burn- ng an awful lot of fossil fuels that year, but the kicker was he addition of massive wildfires in Indonesia to the mix. A long, dry season brought on by El Nino created tin- Herbox conditions in the forests there and led to the fires hat left a smoky haze blanketing much of Southeast Asia. According to a recent report in the journal Nature, the ndonesian fires released an astonishing two billion tons of carbon dioxide into the atmosphere. That’s about a third of the total amount produced by human activities in 1997 and equal to the amount that all living plant life on Earth is capable of removing from the atmosphere in a year. The fires were huge—covering an area twice the size of Belgium—but more significant than the amount of land burning was what was fuelling the flames. In this case, it was peat. Peat consists of compacted and partly decom- posed plant material that accumulates in a water-logged environment. Deposits of peat in tropical regions can be up to 20 metres deep and support vigorous forest growth at their surface, creating thick, virtually impenetrable swampy jungles. Impenetrable, that is, until they are drained and the forests chopped down. In Indonesia, peat swamps are being rapidly lost for timber and rice growing. Part of this process often involves building irrigation channels to remove the water and starting “controlled” fires to help clear the land. During the droughts of 1997, many such fires grew out of control. The peat beneath the forests actually burned even more readily than the trees. Peat is a rich source of carbon and, when dried, can be used as a fuel for cook- ing and heating. With dry peat as a fuel, the fires spread easily. Researchers say that, in total, 80 percent of the emissions from the Indonesian fires came from burning peat. Today, the problem is far from over. Although any remaining fires have been reduced to mere embers, the danger of future blazes has actually increased. That's because the fires have opened up previously inaccessible patches of jungle to logging. Indeed, researchers have found that logging—both legal and illegal—increased 44 November 20, 2002 percent between 1997 and 2000. That has created the right conditions for future fires. And there’s plenty of fuel left. The peat is so thick in many areas that it could fuel as many as ten more fires. For climate researchers, understanding the role of wild- fires in the carbon cycle is essential because current cli- mate models assume a certain consistency in the behav- iour of “carbon sinks”—areas where carbon is stored— such as oceans, forests and peat bogs. The Indonesian fires show that sudden events covering relatively small areas can cause dramatic changes in the amount of car- bon freed into the atmosphere. This, in turn, will increase global warming. The role of peat in the carbon cycle is also of great interest to Canadian scientists. Only ten percent of the world’s peat bogs are found in tropical areas. The vast majority are in temperate areas like Canada. How these vast bogs adapt to a warming climate could play an important role in future warming. As the Nature study shows, human influence on cli- mate is not limited to burning fossil fuels. Land use can obviously play a key role. Conserving carbon sinks like peat bogs is thus an important way to help prevent the addition of yet more greenhouse gas an already unstable atmosphere. To discuss this topic with others, visit the discussion forum at www.davidsuzuki.org.