Top-down assessment of the Asian carbon budget since the mid 1990s.

R L Thompson,A Ganshin,A Ganshin,P K Patra,I T Van Der Laan-Luijkx,S Maksyutov,W Peters,W Peters,P Ciais,P Ciais,B Poulter,B Poulter,R Zhuravlev,T Shirai,T Ziehn,F Chevallier,F Chevallier,F Chevallier,F Chevallier,P Ciais,T Machida,T Nakamura,R Zhuravlev,T Saeki,R M Law,J G Canadell,R Zhuravlev,P Ciais,T Maki,M Ishizawa

doi:10.1038/ncomms10724

Abstract

Increasing atmospheric carbon dioxide (CO2) is the principal driver of anthropogenic climate change. Asia is an important region for the global carbon budget, with 4 of the world's 10 largest national emitters of CO2. Using an ensemble of seven atmospheric inverse systems, we estimated land biosphere fluxes (natural, land-use change and fires) based on atmospheric observations of CO2 concentration. The Asian land biosphere was a net sink of −0.46 (−0.70–0.24) PgC per year (median and range) for 1996–2012 and was mostly located in East Asia, while in South and Southeast Asia the land biosphere was close to carbon neutral. In East Asia, the annual CO2 sink increased between 1996–2001 and 2008–2012 by 0.56 (0.30–0.81) PgC, accounting for ∼35% of the increase in the global land biosphere sink. Uncertainty in the fossil fuel emissions contributes significantly (32%) to the uncertainty in land biosphere sink change.

Highlights

Increasing atmospheric carbon dioxide (CO2) is the principal driver of anthropogenic climate change
The disparities arise from the different inventories on which their estimates were based, for example, CDIAC or EDGAR (Emission Database for Global Atmospheric Research, version 4.2; http://edgar.jrc.ec.europa.eu) and whether a static or evolving spatial distribution was used
For the average over 1996–2012, we find a weak source for the Southeast Asian land biosphere of 0.06 ( À 0.15 to 0.28) PgC per year, which is consistent with observed land-use changes (13% of forested area was lost in Southeast Asia between 1990 and 2010) and with estimates of above ground biomass loss of 0.09 PgC per year for the average over 1993–2012 based on satellite observations[42]

Summary

Introduction

Increasing atmospheric carbon dioxide (CO2) is the principal driver of anthropogenic climate change. Deforestation rates are extensive in Indonesia, where the rate of forest clearance (including forested peatlands) reached 0.84 Mha per year in 2012, surpassing that in Brazil[7] These changes have important consequences for the regional and global carbon budget. CARIBIC data have been utilized in an inversion for CO2 fluxes in South Asia[16] and CONTRAIL data in inversions focusing on Asian CO2 fluxes[17,18,19] These inversions[16,17,18] consistently found a net sink for South Asia of À 0.11 to À 0.37 PgC per year (note that a negative flux is in the direction from the atmosphere to the land/ocean, that is, a sink). We assess the carbon budget of Asia using an ensemble of seven atmospheric CO2 inversions focusing on the regions of East, South and Southeast Asia (see Fig. 1). This study is part of an effort examining the Asian greenhouse gas budget initiated by RECCAP (REgional Carbon Cycle Assessment and Processes20) as part of the international Global Carbon Project (www.globalcarbonproject.org/reccap/)

Methods

Results

Conclusion