Location, location, location: detecting greenhouse gas emissions in Africa

23 October 2020
Africa map from above

In future, emissions as well as carbon sinks over the African continent can be detected with more certainty. According to new research, quality of greenhouse gas measurements in Africa would benefit from atmospheric tall-tower stations spread over the continent with a focus on observations near the African equator. Optimised observation network for greenhouse gases in Africa would reduce the uncertainty of greenhouse gas fluxes over the continent. It would also help to steer the global and continental climate mitigation efforts in the right direction.

Levels of greenhouse gas emissions in Africa are increasing, making it important to level up the quality of measurements in the continent. A recent study suggests where to prioritise stations that measure greenhouse gases in the atmosphere in Africa. Several scientists of the ICOS community were involved in the study that was done within the “Supporting EU-African Cooperation on Research Infrastructures for Food Security and Greenhouse Gas Observations”, SEACRIFOG project.

An optimised network of stations reduces the uncertainty of greenhouse gas emissions. The study views the best solutions to measure three of the most important greenhouse gases contributing to global warming: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Both, human-caused (anthropogenic) and biospheric (produced by living organisms), components of greenhouse gases are covered.

The study addresses each of the main greenhouse gases and their optimal observational locations separately, as well as considers the best network design for the combination of all of these gases. The study also identifies the main factors influencing the network design for each gas.

Based on the findings, CO2 and N2O are observed with the least uncertainty in central Africa, such as in Kisangani in the Democratic Republic of Congo, Dundo in Angola and En Nahud in Sudan, whereas the uncertainty of observational CH4 increases in southern Africa, such as in Amersfoort in South Africa. The optimal solution to observe all three main greenhouse gases combined is to distribute the stations over the African continent and to have also new tall-tower stations placed over the large African equatorial area (between 10°N and 25°S).

The study uses atmospheric inversion models to identify the ideal location of measurement stations that would most reduce the uncertainty in greenhouse gas emissions in Africa. The inversion technique itself relies on atmospheric measurements at ICOS. The resources of the ICOS Carbon Portal were used for the preparation of the emission datasets as well as for the computation of the models.

The SEACRIFOG project’s purpose is to design a greenhouse gas observation system for Africa that would provide African countries with valuable scientific information about their emissions and reduce the observational gaps at the global level.

The study, published in the journal Tellus B: Chemical and Physical Meteorology, is entitled  “Greenhouse gas observation network design for Africa”. The paper is available at: https://doi.org/10.1080/16000889.2020.1824486