Machine Learning Specialist, AKADEMIYA2063 Exploring Methane Emissions in Africa Through Remote Sensing Techniques Dr. Jean Paul Faye In collaboration with M. Mansour Dia, M. Khadim Dia, Dr. Racine Ly

#2024ReSAKSS #2024ATOR Key Messages • Climate change is a worldwide reality, with significant negative impacts across Africa • Adaptation and mitigation strategies are in place to address it, with African countries prioritizing adaptation efforts • African countries also have mitigation options through NDCs where they pledged GHG emission reductions, among others • Assessing GHG budget accurately and in a timely manner is becoming more relevant given the climate variabilities and shots dynamics • Not only granularity is a must to shift from the one size-fits-all to a tailored intervention, but the data also need to be available at a high temporal frequency • In this chapter, we explored methane emissions above African countries using satellite data

#2024ReSAKSS #2024ATOR Key Messages (cont.) • Our results indicate that in 2023, Africa emitted an average of 1,352.97 ppb of CH4, accounting for -30.43% of global average methane emissions +592 ppb Global average Above average Africa average Country Average concentration of CH4 emitted (ppb) Percentage to global average CH4 concentration Mali 1,354.65 -30.35% Namibia 1,331.14 -31,56 % Niger 1,352.92 -30.44 % Nigeria 1374.89 -29.31 % Global methane concentration up to 2023 (~ 1940 ppb) Africa methane emission level Use cases CH4 concentration and percentages (Source: From WORLD METEOROLOGOGICAL ORGANIZATION, WMO-No. 1347)

#2024ReSAKSS #2024ATOR Outline I. Justification of methane (CH4) emission II. Methane emission sources III. Methodology for Measuring Methane Emissions Using Remote Sensing IV. Continental Average Methane Concentration V. Country Average Methane Concentration: Mali, Namibia, Niger, Nigeria VI. Correlation Between CH4 Emissions, LST, and Rainfall Over Cropland VII. Summary

#2024ReSAKSS #2024ATOR Justification of Methane Emissions

#2024ReSAKSS #2024ATOR Justification of Methane Emissions • Though the concentration of CH4 (~1945 ppb) is much lower than those of CO2 (~420 000 ppb), CH4 is more effective at absorbing and re-emitting infrared radiation (heat). • CH4 has a relatively short lifetime in the atmosphere of around 12 years • The removal of 1 ton of CH4 corresponds to around 84 to 86 tons of CO2 removals over 20 years and 28 to 34 tons over 100 years (IPCC, 2023) • Global warming potential of CH4 on a mass basis is 25 x that of CO2 over a 100-year time horizon Concentration of CO2 Concentration of CH4 (From WORLD METEOROLOGOGICAL ORGANIZATION, WMO-No. 1347)

#2024ReSAKSS #2024ATOR Justification of Methane Emissions (cont.) Methane is known to have climate positive feedback Increase of CH4 Increase of Temperature

#2024ReSAKSS #2024ATOR Methane Emissions Sources

#2024ReSAKSS #2024ATOR Methane Emission Sources • Multiple sources are displayed with a few removals • The range of removals does not match that of the sources, leading to an imbalance • Therefore, one of the most effective ways to reduce CH4 emissions is to target the sources • But what are the emission levels from those sources in Africa? Source: Global methane cycle schematic from the IPCC 5th Assessment Report (AR5) Working Group I Chapter 6 (Ciais, Sabine et al. 2013).

#2024ReSAKSS #2024ATOR Methodology for Measuring Methane Emissions Using Remote Sensing

#2024ReSAKSS #2024ATOR Methodology for Measuring Methane Emissions Using Remote Sensing: • Not all layers of Earth’s atmosphere are directly impacted by human (anthropogenic) activities. • The troposphere which extends from the Earth’s surface to 10 km (6 miles) in altitude is the most affected. • The troposphere is, therefore, the layer with the largest concentration of GHGs, such as CH4. Atmospheric layers

#2024ReSAKSS #2024ATOR Methodology for Measuring Methane Emissions Using Remote Sensing: TROPOMI measurements principles Source: Lorente et al. J.: Methane retrieved from TROPOMI: improvement of the data product and validation of the first 2 years of measurements, Atmos. Meas. Tech., 14, 665–684, https://doi.org/10.5194/amt-14-665-2021, 2021 • Data provided by TROPOMI are 7 x 7 km2 approximately at NADIR. • TROPOMI is a passive sensor • S5P covers the entire globe daily • Weekly averaged data are publicly available

#2024ReSAKSS #2024ATOR Methodology for Measuring Methane Emissions Using Remote Sensing: TROPOMI CH4 data validation Source: Lorente et al. J.: Methane retrieved from TROPOMI: improvement of the data product and validation of the first 2 years of measurements, Atmos. Meas. Tech., 14, 665–684, https://doi.org/10.5194/amt-14-665-2021, 2021

#2024ReSAKSS #2024ATOR Continental Average Methane Concentration

#2024ReSAKSS #2024ATOR Continental Average Methane Concentration Average CH4 emissions profile from January 01 to December 31, 2023 • Methane concentrations are higher in regions with abundant wetlands, elevated temperatures, and increased rainfall. • The Data are available at AKADEMIYA2063 for every country since 2018

#2024ReSAKSS #2024ATOR Use cases: Mali, Namibia, Niger, Nigeria

#2024ReSAKSS #2024ATOR Use Case: Mali Average CH4 emissions profile from January 01 to December 31, 2023 Average CH4 emissions in function of time for cropland and non-cropland.

#2024ReSAKSS #2024ATOR Use Case: Namibia Average CH4 emissions profile from January 01 to December 31, 2023 Average CH4 emissions in function of time for cropland and non-cropland.

#2024ReSAKSS #2024ATOR Use Case: Niger Average CH4 emissions profile from January 01 to December 31, 2023 Average CH4 emissions in function of time for cropland and non-cropland.

#2024ReSAKSS #2024ATOR Use Case: Nigeria Average CH4 emissions profile from January 01 to December 31, 2023 Average CH4 emissions in function of time for cropland and non-cropland.

#2024ReSAKSS #2024ATOR Correlation Between CH4 Emissions, LST, and Rainfall Over Cropland

#2024ReSAKSS #2024ATOR Correlation Between CH4 Emissions, LST, and Rainfall Over Cropland Senegal: Average CH4 emissions, LST, and rainfall as a function of time, over cropland areas. • Methane emissions are lower at the peak of rainfall and the lowest point of temperature • Methane emissions reach their peak when a certain amount of water is available, and temperatures are sufficiently high • A decrease in rainfall and an increase in temperature are associated with a rise in methane emissions

#2024ReSAKSS #2024ATOR Summary

#2024ReSAKSS #2024ATOR Summary +592 ppb Global average: 1940 ppb Above average Africa average: 1353 Africa vs the world

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