Indonesia warned about environment toll of swopping rainforests for palm oil

An aerial view of a palm oil plantation in South Sumatra province. Scientists are warning the country that exchanging its rainforests for palm oil plantations risks exacerbating the effects of climate change. PHOTO: REUTERS
A man assists trucks that carry palm oil fruit on a damaged road at Mesuji Raya village in Ogan Komering Ilir, South Sumatra province, Indonesia, on Jan 11, 2017. PHOTO: REUTERS

LONDON (THOMSON REUTERS FOUNDATION) - Indonesia is exacerbating the effects of climate change by swopping its rainforest for palm plantations in a switch that could make water more scarce and wildfires more common, scientists said on Wednesday (Oct 25).

The world's biggest producer of palm oil - which is used in everything from soap to cereal - has lost almost a quarter of its forest since 1990, according to UN and World Bank data.

Outbreaks of haze - the result of fires that are started as a cheap way to clear land for crops - engulf the region each year. They cost the country US$16 billion in 2015 and left more than 500,000 Indonesians with respiratory ailments.

Loss and degradation of forests also account for about 15 per cent of global emissions of greenhouse gases, which contribute to global warming, conservation groups say.

Now, an international team of scientists has found the loss of rainforest has a direct effect on local temperatures, too.

"Land use change from forest to cash crops such as oil palm and rubber plantations... has a surface warming effect, adding to climate change," Alexander Knohl, a co-author of the study published in the journal Biogeosciences, said in a statement.

The study analysed satellite data collected between 2000 and 2015 over the Jambi province in the island of Sumatra, one of the areas most affected by deforestation. It found that overall, average mid-morning surface temperature went up by 1.05 deg C in the region, but increased only 0.45 deg C in untouched forest areas, suggesting deforestation was boosting the effect of climate change.

Land freshly cleared of trees was up to 10 deg C warmer than forest areas. The differences in surface temperature remained when plantations had replaced the old vegetation.

Fully grown palm oil plantations were about 0.8 deg C warmer than forests, while young palm oil plantations were up to 6 deg C warmer, as young trees have fewer and smaller leaves, which transpire less water reducing their cooling effect.

"Also, the soil receives more solar radiation and dries out faster," said lead author Clifton Sabajo of the University of Gottingen in Germany.

Under the landmark Paris accord reached in 2015, rich and poor countries pledged to limit the rise in average world temperatures to well below 2 deg C above pre-industrial times.

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