Low tech biochar production could be a highly effective nature-based solution for climate change mitigation in the developing world

Aim: To compare the climate change mitigation benefits of nature-based solutions for management of municipal green waste with conventional management. Methods: This study analyzed the carbon footprint of managing one ton of municipal green waste (MGW) in Lima Peru under 4 different scenarios: 1) Final disposal in authorized landfill, 2) Final disposal in informal landfill, 3) composting and 4) biochar production using a low-cost, low tech Kon-Tiki reactor. Results: The results demonstrate the very clear potential for climate change mitigation from biochar production using low tech and therefore accessible technology in a typical developing world context. The carbon footprint of producing biochar was lower than for composting and biochar and compost both had carbon footprints significantly lower than landfilling. Conclusion: We argue that the standards used by nascent platforms for trading carbon removal credits generated by biochar should relax the technology requirement to favor engagement and participation of small-scale market participants in low-income countries. Waste management in the developing world presents significant challenges but often starts from a very low base which means there is large potential for reducing emissions, as well as for sequestering carbon.