Super pollutants - Institute For Governance & Sustainable Development

Multilateral approaches to nitrogen pollution are generating synergies between climate change and food security and presenting opportunities to reduce nitrous oxide (N2O) globally. N2O is the most abundant ozone-depleting substance not yet regulated by the Montreal Protocol and a powerful greenhouse gas. Failure to reduce emissions will delay ozone layer recovery and worsen the climate crisis. While cost-effective mitigation technologies to reduce N2O emissions are available, policies and incentives to encourage the uptake of such measures are lacking. The G20, whose membership includes the world’s largest food exporters and fertilizer consumers, is positioned to advance N2O mitigation by supporting coordinated multilateral action. G20 leadership on N2O can support food security by preventing drastic impacts of climate change on food production and safeguarding the ozone layer, which protects agriculture and biodiversity from harmful ultraviolet B radiation. It can also support the achievement of countries’ net-zero climate goals and nationally determined contributions.

Each year, one-third of the total food for human consumption is either lost or wasted even as millions worldwide experience food insecurity. Similarly, over 25 percent of vaccines are wasted each year while millions die from vaccine-preventable illnesses Sustainable cold chain infrastructure can significantly reduce post-harvest food loss and vaccine wastage and deliver social and climate benefits. However, acknowledging the need for cold storage alone does not ensure food security or access to vaccines, and must be supported by policies and resources, including technologies. Cooperation among G20 countries on cold chains can help coordinate the policies and resources necessary to advance food security, public health, and climate change mitigation.

This paper recalls and documents the military leadership under the Montreal Protocol, presents indicative case studies of how technical performance of military systems was maintained or improved by adopting newer technologies and summarizes key lessons from military leadership in protecting the ozone layer. In addition to collaboration on technology development and demonstration, between 1991 and 2009, military organizations from various countries came together to conduct seven workshops specifically to review military ODS uses, share experiences with alternatives, and compare policy approaches to extract and share best practices. Lessons such as this can be applied to developing and adopting technologies that displace the need to emit greenhouse gas while improving the performance of military systems and reducing operating costs.

The agriculture and food system sector is a significant emitter of greenhouse gases (GHGs), primarily methane – associated with livestock and rice production – and nitrous oxide – most directly associated with nitrogen fertilizers, animal manure, and biological nitrogen fixation. There is, however, potential for agriculture to contribute to climate change mitigation. By leveraging the natural role of plants and soils in the cycling of organic carbon, agricultural land can act as a carbon sink through interventions for carbon sequestration like conservation agriculture. Studies estimate a technical potential of soils in global cropland and pasture land to store 2–5 Gt CO2 per year.

PxD and IGSD are partnering on an initiative to collaboratively identify opportunities for innovation in climate change mitigation, particularly for the greenhouse gases most problematic in agricultural production, methane and nitrous oxide, as well as carbon dioxide. This initiative includes four analytical pieces on the opportunities for climate change mitigation by smallholder famers, starting with carbon dioxide sequestration through enhanced rock weathering. Enhanced rock, or silicate, weathering (ERW) is a developing technology which leverages natural mineral weathering to draw carbon from the atmosphere.

The analysis found ERW’s potential for permanent carbon drawdown and agricultural co-benefits makes it an attractive mitigation strategy, particularly in equator and near-equator geographies like the Global South, where there are ideal soil pH, temperature, and moisture conditions for the technology. However, because ERW is a new technology that is still being tested and has yet to be studied in Global South contexts, there remain critical uncertainties around its safety, carbon sequestration potential, probable benefits to farmers, and feasibility. All of these factors must be addressed in order to move the technology forward.

Nitrous oxide (N2O) is both an ozone-depleting substance that damages the stratospheric ozone layer and one of the most potent greenhouse gases (GHGs) contributing to global climate change. As with almost all GHG emissions linked to anthropogenic processes, N2O emissions have increased significantly in recent decades. Agriculture is the main driver for these increases,11 with up to 71% of the increase in emissions from the 1980s to 2007-2016 coming from direct agricultural emissions. In particular, scientists have pointed to the use of nitrogen fertilizer as a key reason for the increasing N2 O atmospheric burden. Most smallholder farmers rely on their own judgment or blanket nitrogen fertilizer recommendations, which can miss critical variations in soil and crop nitrogen needs. Offering farmers in the Global South an accessible and user-friendly way to use nitrogen more efficiently will thus not only help reduce the environmental impact of the use of nitrogen fertilizer in agriculture but also improve farmers’ productivity and profits. Addressing the precision nutrient management gap for smallholder farmers in the Global South is a critical priority for achieving both anti-poverty and climate change goals, especially as the use of nitrogen fertilizer in Global South countries rises in coming years to meet increasing global food demands.

Burning trees for energy delivers a one-two punch against climate change mitigation efforts. Harvesting woody biomass reduces the sequestration potential of forest carbon sinks, while the combustion of woody biomass releases large quantities of carbon into the air. Forest regrowth may not offset these emissions for many decades —well beyond the time the world has left to slow warming to avoid catastrophic impacts from climate change. With little time left to achieve a sustainable and inclusive future, burning forests for energy contributes to warming in the near-term and is not a viable climate solution

This article begins with an overview of the scientific background of why harvesting and burning forests for energy is not a viable solution to climate change or related challenges. This background section includes an explanation of key terminology used in the article. The next section presents the European Union (EU)’s Renewable Energy Directive as a case study on the consequences of including bioenergy in renewable energy policies. Following the case study, the article examines bioenergy policies in the United States and China—the world’s two largest greenhouse gas emitters. The article concludes with policy recommendations to focus government action towards reducing reliance on energy from forest biomass. These recommendations are that governments: (1) re-evaluate their bioenergy policies and ensure lifecycle accounting of forest bioenergy’s climate emissions associated with harvesting and burning forest biomass; (2) end incentives for harvesting forests for fuel and invest in forest preservation, low-emission energy, and low energy demand pathways; and (3) advance international consensus on the harms from forest bioenergy, specifically the impact on climate and biodiversity.

Environmentally harmful product dumping (“environmental dumping”) of new and used low-efficiency cooling appliances with obsolete ozone-depleting and greenhouse gas refrigerants in African countries impoverishes communities, hinders economic development, threatens ecological systems, and harms public health. The use of lowefficiency cooling appliances increases energy demand, leading to higher power plant emissions and limiting affordable energy access in African countries. These low-efficiency appliances and products contain ozone-depleting refrigerants with high global-warming potential (GWP) or ozone-safe refrigerants with high GWP. Environmental dumping of these appliances and products makes it more difficult for countries to meet their international climate obligations and for the world to meet the Paris Agreement’s climate change mitigation targets. Ghana faces high levels of environmental dumping, despite a national ban on importing used cooling appliances and established efficiency standards for new air conditioners and refrigerators. Through the Energy Commission’s Office of Renewable Energy, Energy Efficiency, & Climate Change (REEECC), the government of Ghana is partnering with the Institute for Governance & Sustainable Development (IGSD) to stop environmental dumping. This article provides a list of interventions that can be implemented by Ghana, by governments in countries that export to Ghana, and by industry and other stakeholders. Notably, these actions focus on the shared responsibility of exporting countries and manufacturers by calling on exporting countries to update and enhance enforcement of their laws, and on global manufacturers to stop exporting inefficient products with obsolete refrigerants to Ghana and other African countries.

The ongoing and projected impacts from human-induced climate change highlight the need for mitigation approaches to limit warming in both the near term (<2050) and the long term (>2050). We clarify the role of non-CO₂ greenhouse gases and aerosols in the context of near-term and long-term climate mitigation, as well as the net effect of decarbonization strategies targeting fossil fuel (FF) phaseout by 2050. Relying on Intergovernmental Panel on Climate Change radiative forcing, we show that the net historical (2019 to 1750) radiative forcing effect of CO₂ and non-CO₂ climate forcers emitted by FF sources plus the CO₂ emitted by land-use changes is comparable to the net from non-CO₂ climate forcers emitted by non-FF sources. We find that mitigation measures that target only decarbonization are essential for strong long-term cooling but can result in weak near-term warming (due to unmasking the cooling effect of coemitted aerosols) and lead to temperatures exceeding 2 °C before 2050. In contrast, pairing decarbonization with additional mitigation measures targeting short-lived climate pollutants and N₂O, slows the rate of warming a decade or two earlier than decarbonization alone and avoids the 2 °C threshold altogether. These non-CO₂ targeted measures when combined with decarbonization can provide net cooling by 2030 and reduce the rate of warming from 2030 to 2050 by about 50%, roughly half of which comes from methane, significantly larger than decarbonization alone over this time frame. Our analysis demonstrates the need for a comprehensive CO₂ and targeted non-CO₂ mitigation approach to address both the near-term and long-term impacts of climate disruption.

Scientific studies show that fast actions to reduce near-term warming are essential to slowing self-reinforcing climate feedbacks and avoiding irreversible tipping points. Yet cutting CO₂ emissions only marginally impacts near-term warming. This study identifies two of the most effective mitigation strategies to limit near-term warming beyond CO₂ mitigation, namely reducing short-lived climate pollutants (SLCPs) and promoting targeted nature-based solutions (NbS), and comprehensively reviews the latest scientific progress in these fields. Studies show that quickly reducing SLCP emissions, particularly hydrofluorocarbons (HFCs), methane, and black carbon, from all relevant sectors can avoid up to 0.6 °C of warming by 2050. Additionally, promoting targeted NbS that protect and enhance natural carbon sinks, including in forests, wetlands, grasslands, and agricultural lands, can avoid emissions of 23.8 Gt of CO₂e per year in 2030, without jeopardizing food security and biodiversity. Based on the scientific evidence, the paper provided a series of policy recommendations on SLCPs and NbS.

Developing a Global Nitrous Oxide Reduction Policy for A Food-Secure Future