Climate-forcing BC+SO4 aerosols and CH4+CO gases from India: Observational constraints on sources with isotope fingerprinting

S Asia is home to 1.5 billion people and to 14 of the World’s 15 most polluted cities. its emissions of pollutants have severe effects on climate and the quality of the air people breathe, as well as on food and water security through cascade effects.Since the level of scientific understanding is high for the global radiative forcing of anthropogenic CO2, this proposed study focuses on four other important climate-affecting species (BC aerosols, SO4 aerosols, CH4, CO) whose effective radiative forcing are together of the same scale as CO2, but whose sources and effects are much more uncertain.

Further, in contrast to trends in much of the rest of the World, the emissions of these appear here to be increasing.

Unfortunately, the global atmospheric observatory programs have very poor coverage of the South Asian region.The overarching purpose is to quantitatively apportion the relative contribution of the emission sources for these four key climate forcers released over South Asia.

The project will advance source-diagnostic isotope fingerprinting at two strategic atmospheric observatories: The Bangladesh Climate Observatory, intercepting the integrated pollution outflow of the Indo-Gangetic Plain and The Maldives Climate Observatory in Indian Ocean, intercepting the even broader outflow from the Indian subcontinent.Isotope fingerprinting of each climate forcer will reveal the relative importance of key emission sources – to the benefit also for effective mitigation policies.