Browsing by Author "Ichii, Kazuhito"

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Land use change and El Niño-Southern Oscillation drive decadal carbon balance shifts in Southeast Asia
(2018-03) Kondo, Masayuki; Ichii, Kazuhito; Patra, Prabir K.; Canadell, Joseph G.; Poulter, Benjamin; Stitch, Stephen; Calle, Leonardo; Liu, Yi Y.; van Dijk, Albert I. J. M.; Saeki, Tazu; Saigusa, Nobuko; Friedlingstein, Pierre; Arneth, Almut; Harper, Anna B.; Jain, Atul K.; Kato, Etsushi; Koven, Charles D.; Li, Fang; Pugh, Thomas A. M.; Zaehle, Sonke; Wiltshire, Andy; Chevallier, Frederic; Maki, Takashi; Nakamura, Takashi; Niwa, Yosuke; Rödenbeck, Christian
An integrated understanding of the biogeochemical consequences of climate extremes and land use changes is needed to constrain land-surface feedbacks to atmospheric CO2 from associated climate change. Past assessments of the global carbon balance have shown particularly high uncertainty in Southeast Asia. Here, we use a combination of model ensembles to show that intensified land use change made Southeast Asia a strong source of CO2 from the 1980s to 1990s, whereas the region was close to carbon neutral in the 2000s due to an enhanced CO2 fertilization effect and absence of moderate-to-strong El Niño events. Our findings suggest that despite ongoing deforestation, CO2 emissions were substantially decreased during the 2000s, largely owing to milder climate that restores photosynthetic capacity and suppresses peat and deforestation fire emissions. The occurrence of strong El Niño events after 2009 suggests that the region has returned to conditions of increased vulnerability of carbon stocks.
Regional Carbon Fluxes from Land Use and Land Cover Change in Asia, 1980-2009
(2016-07) Calle, Leonardo; Canadell, Josep; Patra, Prabir K.; Ciais, Philippe; Ichii, Kazuhito; Tian, Hui; Kondo, Masayuki; Piao, Shilong; Arneth, Almut; Harper, Anna B.
We present a synthesis of the land-atmosphere carbon flux from land use and land cover change (LULCC) in Asia using multiple data sources and paying particular attention to deforestation and forest regrowth fluxes. The data sources are quasi-independent and include the U.N. Food and Agriculture Organization-Forest Resource Assessment (FAO-FRA 2015; country-level inventory estimates), the Emission Database for Global Atmospheric Research (EDGARv4.3), the 'Houghton' bookkeeping model that incorporates FAO-FRA data, an ensemble of 8 state-of-the-art Dynamic Global Vegetation Models (DGVM), and 2 recently published independent studies using primarily remote sensing techniques. The estimates are aggregated spatially to Southeast, East, and South Asia and temporally for three decades, 1980–1989, 1990–1999 and 2000–2009. Since 1980, net carbon emissions from LULCC in Asia were responsible for 20%–40% of global LULCC emissions, with emissions from Southeast Asia alone accounting for 15%–25% of global LULCC emissions during the same period. In the 2000s and for all Asia, three estimates (FAO-FRA, DGVM, Houghton) were in agreement of a net source of carbon to the atmosphere, with mean estimates ranging between 0.24 to 0.41 Pg C yr−1, whereas EDGARv4.3 suggested a net carbon sink of −0.17 Pg C yr−1. Three of 4 estimates suggest that LULCC carbon emissions declined by at least 34% in the preceding decade (1990–2000). Spread in the estimates is due to the inclusion of different flux components and their treatments, showing the importance to include emissions from carbon rich peatlands and land management, such as shifting cultivation and wood harvesting, which appear to be consistently underreported.