The recently concluded 21 st Conference of the Parties (COP21) under the United Nations Framework Convention on Climate Change (UNFCCC) agreed to limit the increase in global temperature to less than 2oC above pre-industrial levels, with a more aspirational target of 1.5 oC. Achieving these policy goals will require extraordinary input from the scientific community to define anthropogenic emission targets that account for natural biosphere sources and sinks of carbon dioxide (CO2), consistent with the climate targets. Asian countries, being densely populated and emerging global economic powers, are key players in defining future emission trajectories. The average fossil emissions from the three regions are estimated to be 2.4, 0.5 and 0.3 petagrammes of carbon per year (PgC yr -1) for East, South and Southeast Asia, respectively, and have increased by 67, 58 and 33 percent over the period 2003–2012. Here, we estimate land biosphere CO2 fluxes using: 1) simulations of terrestrial ecosystem models driven with global and regional atmospheric and climate observations and 2) atmospheric CO2 inverse models. Based on observations of atmospheric CO 2 and inverse models, we show that on average over the period 2003–2012, the land biosphere (excluding fossil fuel emissions) in the three Asian regions in our study is either a CO2 sink (0.35 PgC yr-1 in East Asia) or source neutral (South and Southeast Asia). Consistently, our terrestrial ecosystem modelling suggests that the land biosphere of South and Southeast Asia were nearly neutral, but disagrees for East Asia.