IHE Delft, in collaboration with international partners at International Livestock Research Institute (Kenya), Karlsruhe Institute of Technology (Germany), ETH Zurich (Switzerland) have now identified previously unknown sources of a powerful greenhouse gas in sub-Saharan Africa associated with livestock rearing.
The results were published in Nature Communications, a top international peer-reviewed journal, in an article called “Livestock enclosures in drylands of Sub-Saharan Africa are overlooked hotspots of N2O emissions.”
The molecule nitrous oxide, known as laughing gas or N2O, contributes about 10% to the global greenhouse effect. IHE Delft, in collaboration with international partners at International Livestock Research Institute (Kenya), Karlsruhe Institute of Technology (Germany), and ETH (Switzerland) have now identified previously unknown sources of N2O in sub-Saharan Africa. Around a quarter of the world's livestock of cattle, goats and sheep lives there, an animal population that has more than doubled since 1960. Most of these animals live in semi-arid and arid areas where they roam during the day and are kept in pens at night to protect them from wildlife predators. However, the manure that accumulates in the pens is usually not used by the herders, so it accumulates in piles, sometimes up to several meters high. This study shows that even 40 years after the pens are abandoned, the manure pile still releases considerable amounts of N2O, more than ten times than the normal savannah. They thus contribute at least 5% to Africa's N2O emissions, with a rapidly increasing trend. These emissions are not taken into account in the current emission estimates for sources of atmospheric nitrous oxide, nor are emissions from abandoned animal pens in other semi-arid areas in the world. This research suggests that we need more understanding of animal contributions to greenhouse gas emission in similar landscapes.