Indonesia – Roads turned rivers brown, houses were washed away by strong currents and corpses were pulled from the mud during deadly flash floods and mudslides after torrential rains hit West Sumatra in early March, making it one of Indonesia’s deadliest natural disasters.
Authorities blamed the flooding on heavy rains, but environmental groups have said the disaster represents the latest example of deforestation and environmental degradation intensifying the effects of bad weather across Indonesia.
“This catastrophe has not only been caused by extreme weather factors, but by the ecological crisis,” the Indonesian Forum for the Environment wrote in a statement. “If the environment continues to be ignored, we will continue to reap ecological disasters.”
Indonesia, a vast tropical archipelago stretching across the equator, is home to the world’s third-largest rainforest, with a variety of endangered wildlife, including orangutans, elephants, giants and blooming forest flowers. Some live nowhere else.
For generations, the forests have also provided livelihoods, food and medicine, while playing a central role in the cultural practices of millions of Indonesia’s indigenous residents.
According to Global Forest Watch, more than 74 million hectares of Indonesian rainforest – an area twice the size of Germany – have been cleared, burned or degraded since 1950 to grow palm oil, paper, rubber, mining and other commodities.
Indonesia is the world’s largest producer of palm oil, a major exporter of charcoal and a leading producer of pulp. It also exports oil and gas, rubber, tin and other resources. In addition, it has the world’s largest reserves of nickel, a critical material for electric vehicles, solar panels and other goods needed for the transition to green energy.
Indonesia is one of the world’s largest emitters of greenhouse gases, from fossil fuel burning, deforestation and peatland fires, according to the Global Carbon Project.
It is also highly vulnerable to the impacts of climate change, including extreme events such as floods and droughts, long-term changes in sea level rise, alterations in rainfall patterns and increasing temperatures, according to the World Bank. In recent decades the country has already begun to feel the effects of climate change: more intense rainfall, landslides and floods during the rainy season, and more fires during a longer dry season.
But forests can help because they play a vital role in reducing the impact of some extreme weather events, said Aida Greenbury, a sustainability expert who focuses on Indonesia.
Floods can be slowed by trees and vegetation that absorb water and reduce erosion. In the dry season, forests release moisture that helps mitigate the effects of droughts, including fires.
But when forests are reduced in size, those benefits also diminish.
A 2017 study revealed that forest conversion and deforestation expose bare soil to rainfall, leading to soil erosion. Frequent harvesting activities-such as those on oil palm plantations-and the removal of soil vegetation lead to increased soil compaction, causing rain to run off the surface instead of entering groundwater reservoirs. According to the study, downstream erosion also increases sediment in rivers, making them shallower and increasing the risk of flooding.
After the deadly floods in Sumatra in early March, West Sumatra Governor Mahyeldi Ansharullah said there were strong indications of illegal logging around the flood and landslide affected sites. That, coupled with extreme rainfall, inadequate drainage systems and inadequate housing development contributed to the disaster, he said.
Environmental experts and activists have pointed out that deforestation also worsens disasters in other regions of Indonesia: In 2021, environmental activists partially blamed deadly floods in Kalimantan on environmental degradation caused by large-scale mining and palm oil operations. In Papua, deforestation was partly blamed for floods and landslides that killed more than 100 people in 2019.