IMIS

A range of the emissions due to flaring is estimated based on the range of emission factors (EFs) for each chemical species. An average decrease in CO₂ emissions of about 30% is found over Africa from 1995 to 2010, with Nigeria being the largest contributor to this reduction (up to 50%). Changes in the spatial distribution with time indicate local increases, particularly at offshore platforms, which are attributed to a lack of regulations as well as aging infrastructures in oil and gas fields.

Comparisons with current inventories reveal differences in the location and magnitude of point source emissions. For chemical compounds such as NMVOCs and CH₄, the ECLIPSE and EDGAR country-level values are considerably higher than the highest flaring emission estimated in this study for 2005. For species such as CO, OC, BC, SO₂ and NO_x, the emissions provided by the ECLIPSE and EDGAR inventories are generally within the same order of magnitude as the average values found in this study, with the exception of OC, BC and SO₂ in which EDGAR provides much lower emissions. These discrepancies are likely due to either differences in the methodologies used to estimate the emissions, in the values of the emission factors considered, or in the definition of flaring sector. Our current estimations suggest that BC, CH₄ and CO₂ flaring emissions in Africa account for 1–15% (on average 7%), 0.5–8% (on average 2%) and 8–13% (on average 11%) of African total anthropogenic emissions, respectively. The contribution of flaring to African anthropogenic emissions varies widely among countries. For example, in Nigeria the average emissions due to flaring are estimated to be as high as 18% for BC, 10% for CH₄ and 50% for CO₂, which is significantly greater than the continental average and highlights the importance of emissions in flaring areas.