An increase of global temperatures has already resulted in prolonged drought, heavy rainfall leading to floods and tidal waves in Indonesia, putting the archipelago's rich biodiversity at risk, said the report, released on Monday.
"Emissions resulting from deforestation and forest fires are five times those from non-forestry emissions. Emissions from energy and industrial sectors are relatively small, but are growing very rapidly," it added.
"This may lead to harmful effects on agriculture, fishery and forestry, resulting in threats to food security and livelihoods," said the report, which comes ahead of this week's G8 summit in Germany where global warming is major item on the agenda.
  The report is a review of published information compiled by PT Pelangi Energi Abadi Citra Enviro (PEACE), a consulting arm of an Indonesian research institute dealing with the environment, and was sponsored by the World Bank and the British government.
Indonesia's total annual carbon dioxide emissions stand at 3.014 billion tonnes after the United States, the world's top emitter with 6.005 billion tonnes followed by China at 5.017 billion tonnes, according to data from the report.
Indonesia's yearly carbon dioxide emissions from energy, agriculture and waste are around 451 million tonnes while forestry and land use change are estimated to account for a staggering 2.563 billion tonnes, said the report, titled "Indonesia and Climate Change: Current Status and Policies".
Climate change would also increase average sea levels, which in turn would reduce farming and coastal livelihoods in Indonesia, a country of about 17,000 islands where millions depend on fishing and farming.
"Even if forest fires were taken out of the equation, Indonesia would still be one of the largest greenhouse gas emitters," said Agus P. Sari of PEACE.
He said the figures cited in the report were debatable.
"But more important than those figures is acknowledgment that Indonesia has a big problem, that Indonesia contributes a lot," he told a conference to launch the report.
RAIN FORESTS
Indonesia's rain forests are being stripped rapidly because of illegal logging and palm oil plantations for bio-fuels, and some environmentalists say they could be wiped out altogether within the next 15 years.
According to some estimates, the tropical Southeast Asian country -- whose forests are a treasure trove of plant and animal species including the endangered orangutans -- has already lost an estimated 72 percent of its original frontier forest.
Forest fires, often deliberately lit by farmers as well as timber and oil palm plantation owners, are a regular occurence on Indonesia's Sumatra island and its portions of Borneo island during the dry season.
Indonesia's neighbours have grown increasingly frustrated with Jakarta's failure to tackle the dry season fires, which last year triggered fears of a repeat of months of choking haze in 1997-98 that cost the region billions in economic losses.
The report is an effort to raise awareness on how climate change "is a real threat to Indonesia", said Joe Leitmann, chief environmentalist at the World Bank in Jakarta.
Indonesia will host the next annual Kyoto Protocol meeting on the resort island of Bali in December and this "puts the country in a strong position to lead on developing international action and incentives to reduce emissions from deforestation", said Mike Harrison of Britain's Department for International Development.
In 2004, Indonesia ratified the protocol, which requres about 35 developed countries to lower their emissions to below their 1990 levels between 2008-2012. Developing nations are excluded from the emissions cuts during the first phase.