* Land burned in 2019 fires nearly twice recorded officially-study
* Study does show deforestation rate slowing in 2017-2020
* Indonesia says committed to reducing deforestation
* Environmental groups call for greater transparency (Adds environmental campaigner's quote in paragraph 14)
By Fathin Ungku
SINGAPORE, Jan 14 (Reuters) - Indonesia's devastating forest fires in 2019 burned nearly twice as much land as was officially reported, according to a recent study, raising concerns among environmental campaigners over the government's transparency regarding deforestation.
The Southeast Asian country, which has the largest rainforests outside of the Amazon and Congo, has razed large swathes of land to accommodate its palm, pulp and paper industries.
The fires in 2019 blanketed Indonesia and the region with haze, causing 900,000 people to report respiratory illnesses and costing $5.2 billion in losses, the World Bank said https://www.reuters.com/article/us-indonesia-environment-idUSKBN1YF0FJ.
The study published in the Earth System Science Data journal in November found 3.1 million hectares (7.7 million acres) were burned in 2019 - an area bigger than Belgium - compared to 1.6 million hectares reported by the forestry ministry.
"We observed a larger damaged area than official estimates because ground-breaking technology enabled us to detect more small burns and more very large ones," one of the study's authors, David Gaveau, told Reuters.
"We used better satellite data, machine learning and Google's super-computers."
Nonetheless, in line with official data, the study found that the rate of deforestation in Indonesia had fallen over the last four years, though its calculations differed, Gaveau said.
When Gaveau first reported his findings in December 2019, Indonesian authorities said his research was not credible as it was not peer reviewed at the time.
Gaveau said he had sent the latest peer reviewed findings to the Ministry of Environment and Forestry.
An official in charge of forest fires at the ministry did not immediately respond to requests from Reuters seeking comment.
The ministry has previously said it is committed to reducing deforestation although it cannot completely stop it as clearing land is needed for development.
Instead, it aims to achieve a "carbon net sink" https://www.reuters.com/business/cop/indonesia-says-wants-reduce-deforestation-not-completely-end-it-2021-11-05 in its forestry sector by 2030, meaning that the sector will absorb more greenhouse gas emissions than it emits.
Wahyu Perdana, a campaigner at environmental rights group WALHI, urged the government to ensure it was transparent about deforestation data.
"Weak transparency will have an impact on... law enforcement," Perdana said. "Weak law enforcement in the case of forest fires will make it difficult to suppress deforestation."
Greenpeace Indonesia forest campaigner Asep Komarudin also said transparency was important to avoid potential issues with international fund transfers for forest nations under global climate agreements. (Reporting by Fathin Ungku Editing by Ed Davies & Simon Cameron-Moore)
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