Despite mild El Niño, scientists expect severe Indonesian fires

By Curtis Runyan

(WASHINGTON, DC, February 2003) The current El Niño weather pattern that has caused drier than usual weather across Southeast Asia since last July is once again expected to fan fires in Indonesia’s rainforests. El Niño conditions have caused below-average rainfall, which have left many parts of the country vulnerable to drought and fires.

Severe El Niño events in 1982-83 and 1997-98 caused prolonged droughts that left forests susceptible to fires that swept across large sections of the country. The 1997-98 fires, for example, damaged 10 million hectares of land, contributed to the deaths of more than 500 people, and cost an estimated $9 billion.

The current “moderate” El Niño episode is expected to last till the end of April. Waters in the Pacific have warmed by 1.5 to 2 degrees Celsius above normal, whereas the “severe” El Niño in 1997 raised ocean temperatures 3 to 4 degrees above normal.

Still, the World Meteorological Organization (WMO) warned of an “unusual warmth in the far western tropical Pacific” that could further exacerbate dry conditions. “The warming in the tropical Pacific is not expected to reach levels that were experienced in 1997-98. Nonetheless, severe consequences in some regions are to be expected,” said the WMO statement.

New research is finding that parts of Indonesia’s expansive rainforests are increasingly vulnerable to drought—and to fire—even in mild El Niño conditions and in normal years. Lisa Curran, a professor at the Yale School of Forestry who has spent the last 20 years studying Indonesia’s forests, has found that human impacts on the forests, not just climate conditions, are a key factor behind the droughts and tropical forest fires. “We are looking at the interactions between people, fire, climate, and land use, and we are finding that the synergies are extreme—largely due to land-use change,” she said.

Drought-like conditions aren’t sticking to traditional patterns observed in the past 30 years. “The droughts are getting more frequent and irregular,” Curran says. “We’re seeing longer periods without rainfall; we’re seeing long droughts in May, when there have never been droughts in May. Haze [from forest fires] was coming in early June last year, when it wouldn’t come until August previously.”

A study published in 2001 in the journal Nature reported that Indonesian forests that had recently been thinned by logging or damaged by past fires were far more likely to burn than undisturbed forests. In the 1997-98 fires, less than 6 percent of pristine forests burned, while fires spread through 59 percent of thinned forests. The extent of the fire damage was also considerably worse in forests that had been previously logged.

Indonesian timber companies often leave in their wake large amounts fuel—brush, dead timber, and damaged trees. Slash-and-burn farmers clear land to plant crops. Plantation firms deliberately set fires to clear land to grow their crops. In fact, in 1997 satellite imagery pinpointed most fires near to or in timber and oil palm plantations. Poor forest management is increasingly being seen as a major contributor to the fires. “It’s definitely not just El Niño,” says Curran.

Since 1950 Indonesia has lost more than a third of its forests. Forest cover has fallen from 162 million hectares to 98 million hectares. And the rate of deforestation is speeding up. In 1980 the country lost 1 million hectares. Today the rate is 2 million hectares per year. About 3 hectares of forest are now cleared every minute. Illegal logging increasingly accounts for a massive share of the forests cleared. More than 10 million hectares of forest have been cleared illegally in Indonesia, according to one forestry official. “Deforestation on this scale, at this speed, is unprecedented,” says Emily Matthews of the World Resources Institute, co-author of the 2002 report, The State of the Forest: Indonesia.

While drought conditions this year may not be as severe as five years ago, many of the forestry practices common during the last epidemic of fires remain in place. Hundreds of fire “hotspots” had already been detected in September and October 2002 before the region’s monsoon rains began. “Every year there are a lot more hotspots turning up in the satellite images,” says Curran. (WRI Features, 705 words)