Climatic benefits of black carbon emission reduction when India adopts the US onroad emission level

Abstract

India is known to emit large amounts of black carbon (BC) particles, and the existing estimates of the BC emission from the transport sector in the country widely range from 72~456 Gg/year (for the 2000's). First, we reduce the uncertainty range by constraining the existing estimates by credible isotope analysis results. The revised estimate is from 74~254 Gg/year. Second, we derive our own BC estimate of the transport section in order to gain a new insight into the mitigation strategy and value. Our estimate shows that the transport section BC emission would be reduced by about 69 % by adopting the US standards. The highest emission reduction comes from the vehicles in the 5-10 year old age group. The minimum emission reduction would be achieved from the vehicles in the 15-20 year old age category since their population is comparatively small in comparison to other age categories. The 69 % of 74~254 Gg/year is 51~175 Gg/year, which is the estimated BC emission reduction by switching to the US on-road emission standard. Assuming that global BC radiative forcing is 0.88 Wm −2 for 17.8 Tg/year of BC emission, we find that the reduced BC emission translates into −0.0025~−0.0087 W m −2 in global forcing. In addition, we find that 51~175 Gg of BC emission reduction amounts to 0.046 -0.159 B carbon credits which are valued at 0.56 -1.92 B US dollars (using today's carbon credit price). In a nutshell, India could potentially earn billions of dollars per year by switching from the current on-road emission levels to the US levels.