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Masayuki Kondo
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A new regional assessment shows that Southeast Asia is a major net source of greenhouse gases, with land-use change and rising fossil fuel use overwhelming natural carbon sinks, reservoirs that store carbon-containing chemical compounds for a long period.
Map highlighting Southeast Asia’s peatlands, which act like giant carbon storage areas but are at risk of deforestation and drainage (Adapted from Masayuki Kondo et al., Global Biogeochemical Cycles, September 24, 2025).
A comprehensive assessment of Southeast Asia’s greenhouse gas balance carried out by an international team of researchers led by 亚色视频, shows that the region is a significant source of climate-warming gases. The leading causes are deforestation, damage to peatland, fires, and a rapid rise in fossil fuel use. The study, published in the journal on September 24, 2025, highlights how difficult it will be for countries in the region to reach climate neutrality. It stresses the need for countries to work together as soon as possible.
The team measured all major sources and sinks of carbon dioxide, methane, and nitrous oxide across Southeast Asia from 2000 to 2019. They found that natural ecosystems, including forests, wetlands, mangroves, and peatlands, continue to store and absorb large amounts of carbon. However, this natural absorption is not enough to offset human-driven emissions resulting from land-use change and burning of fossil fuels.
REgional Carbon Cycle Assessment and Processes 2 (RECCAP2) greenhouse gas (GHG) budget assessment framework for Southeast Asia. The carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes are indicated by brown, green, and blue arrows, respectively. All sources and sinks must be accounted for in the estimation. (Adapted from Masayuki Kondo et al., Global Biogeochemical Cycles, September 24, 2025).
“Southeast Asia has some of the most carbon-rich forests and wetlands in the world, but the region is still adding more greenhouse gases to the atmosphere than it removes,” said , associate professor at , the study’s lead and corresponding author. “The primary reasons are continued deforestation and the drying and draining of peatlands. Fires and the fast-growing use of coal are making things even worse.”
The study found that cutting down forests and converting them to other types of land released more greenhouse gases than any other activity during the 20-year study period.
“Forests are trying to grow back, but they can’t keep up with the rate at which land is being cleared,” says Kondo. “If countries protect and restore forests, they will see immediate and meaningful climate benefits.”
Fires, including extensive peat fires during El Ni?o dry years, were the next biggest contributor, and peat decomposition from drained peatlands also released large amounts of emissions.
The researchers also found a dramatic 48% rise in emissions from fossil fuels. Oil was the leading source of emissions in earlier years, but coal use began rising sharply after 2005 and surpassed oil emissions in 2018. Without substantial changes in energy policy, the study warns that coal could remain a major driver of future emissions.
“The jump in coal emissions is something we’ve never seen before in this region,” said Kondo. “If all the planned coal plants are built, the power sector’s emissions could increase even more, making it much harder for Southeast Asia to reach climate neutrality.”
The study also notes that parts of the region still lack basic greenhouse gas monitoring systems, making it difficult to provide highly accurate estimates. More measurement sites, better models, and closer links between scientific data and national policy decisions will all be needed.
To help address this gap, the researchers have launched a new international network called the League of geophysical research eXcellences for tropical Asia, or LeXtra. The network aims to strengthen greenhouse gas monitoring, improve models, and support data sharing across Southeast Asia.
By clearly identifying where greenhouse gases come from and where they are absorbed, the study offers guidance for more effective climate strategies. “The biggest impact would come from reducing emissions from land-use change and fossil fuels,” said Kondo. “Southeast Asia still has a chance to grow its economy while protecting the climate, but the window of opportunity is getting smaller.”
The research team included Prabir K. Patra, JAMSTEC and RIHN (Japan); Josep G. Canadell, CSIRO (Australia); Philippe Ciais, Ronny Lauerwald, Marielle Saunois, Université Paris‐Saclay (France); Richard A. Houghton, Woodwell Climate Research Center (USA); Akihiko Ito, The University of Tokyo and NIES (Japan); Chandra S. Deshmukh, Asia Pacific Resources International Ltd. (Indonesia); Tomo'omi Kumagai, The University of Tokyo, Nagoya University (Japan) and University of Hawai?i at Mānoa (USA); Xiangzhong Luo, National University of Singapore (Singapore); Umakant Mishra, Sandia National Laboratories and Lawrence Berkeley National Laboratory (USA); Atul K. Jain, University of Illinois at Urbana–Champaign (USA); Wei Li, Tsinghua University (China); Gerbrand Koren, Utrecht University (The Netherlands); Stephen Sitch, University of Exeter (UK); Ben Poulter, Spark Climate Solutions (USA); Hanqin Tian, Boston College (USA); Ana Bastos, Max Planck Institute for Biogeochemistry (Germany); Judith A. Rosentreter, Southern Cross University (Australia); Tazu Saeki & Nobuko Saigusa, NIES (Japan); Ingrid T. Luijkx, Wageningen University and Research (The Netherlands); Takashi Maki, Meteorological Research Institute (Japan); Takashi Nakamura, Japan Meteorological Agency (Japan); Kirari Hirabayashi, 亚色视频 (Japan); and Takeshi Hirano, Hokkaido University (Japan).
This study was funded by the Integrated Land Ecosystem-Atmosphere Processes Study (iLEAPS); the Arctic Challenge for Sustainability II (ArCS-II) project by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT); the Environmental Restoration and Conservation Agency of Japan; the JSPS KAKENHI; French state aid, managed by ANR; and the NASA LCLUC program.
About the study
Journal: Global Biogeochemical Cycles
Title: The Greenhouse Gas Budget of Southeast Asia for 2000–2019 and Pathways Toward Climate Neutrality
Authors: Masayuki Kondo, Prabir K. Patra, Josep G. Canadell, Philippe Ciais, Richard A. Houghton, Akihiko Ito, Chandra S. Deshmukh, Tomo'omi Kumagai, Xiangzhong Luo, Umakant Mishra, Atul K. Jain, Wei Li, Gerbrand Koren, Stephen Sitch, Ben Poulter, Hanqin Tian, Ana Bastos, Ronny Lauerwald, Judith A. Rosentreter, Naveen Chandra, Tazu Saeki, Marielle Saunois, Ingrid T. Luijkx, Takashi Maki, Takashi Nakamura, Kirari Hirabayashi, Takeshi Hirano, Nobuko Saigusa
Date: September 24, 2025
DOI:
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