Reduce HFCs, Methane and Black Carbon Emissions


Methane, black carbon, tropospheric ozone, and some hydrofluorocarbons (HFCs)–commonly referred to as short-lived climate pollutants (SLCPs) –are potent emissions that pack a lot of punch in a short time. Methane’s average life span is about 12 years, unlike CO2 which stays in the atmosphere for a very long time, from decades to centuries [1].  Black carbon and tropospheric ozone have an even shorter atmospheric life spans – typically only a few days or weeks –resulting in direct regional climate, environmental and health impacts as well as global impacts.

Despite their shorter life span, SLCPs are having a huge impact on our climate, responsible for at least 40% of the radiative forcing that is heating the planet globally[1]. Therefore, aggressively reducing SLCPs in the next decade is one of the most effective ways of keeping global temperatures from rising above the 1.5 degrees Celsius threshold [2, 3].  The good news is that once we reduce these emissions, we can lower their climate impacts.  This is the low-hanging fruit.

Methane accounts for a large and growing percentage of global greenhouse gas emissions. Each molecule of methane emitted is inherently more than 100 times more potent than CO2 in trapping heat. One of the main climate change culprits in the food supply chain, methane is produced primarily from the enteric fermentation of ruminant livestock such as cattle and sheep, and is released when the animals burp as well as from their manure. Methane is also released by rice cultivation –the warm, waterlogged soil of rice paddies provides ideal conditions for methanogenisis –the formation of methane by microorganisms. It is also released by landfills, the burning of biomass, coal mining and other sources, including natural gas and oil production. [4]

New technologies and practices can curb methane from rice growing such as through periodic field drying (see the Lotus Foods video below for more information). Using anaerobic digestion to capture methane from livestock manure is an effective approach to convert waste into energy while reducing methane emissions[5]. In addition, simple changes such as avoiding adding straw to manure, applying manure to fields as quickly as possible, and avoiding wet conditions when applying manure can reduce the emission of methane[6]. There are promising solutions to enteric emissions with feed additives and modifying feed to decrease methanogenisis such as adding seaweed and high omega-3 feeds to the diet of livestock. Modifications in fertilization regimes, including increased use of natural compost in lieu of synthetic fertilizers, and other methods to reduce reliance on petroleum and natural gas-reliant inputs.

Check out how Lotus Foods achieves 30%-60% reductions in methane emissions from rice production.

Black carbon is the fine particulate or soot that results from the incomplete combustion of fossil fuels (diesel fuel, in particular) and biomass - primarily in the form of forests and crop residues. It warms the atmosphere by absorbing solar radiation and emitting it as heat, changes cloud formation and rain patterns, and darkens the surface of snow and ice, which accelerates heat absorption and melting[7]. Black carbon is also responsible for premature deaths and crop damage each year[8]. Despite the fact that black carbon only remains in the atmosphere for a few weeks at most, it is estimated to be the second or third largest cause of climate change behind CO2, with methane being the other major contributor [9].

Opportunities to reduce black carbon emissions from agriculture and food chain operations abound, especially by substantially reducing burning of crop residues and lands cleared for crops, by ensuring that diesel engines used in transport meet the highest pollution standards or operate on alternative fuels, and through on-site non-grid connected energy production. 

HFCs from refrigerants in air conditioning, cold chain transportation and storage are thousands of times more potent than CO2. Used as replacements for ozone-depleting substances (chlorofluorocarbons), HFCs are one of the fastest growing climate pollutants. Solutions for HFCs in refrigerants include managing leakage and recovery, enhancing energy efficiency within the cold chain, and using alternative refrigerants and other alternative technologies such as transcritical CO2 [12]

Businesses that commit to reducing SLCPs –such as potent methane, black carbon, tropospheric ozone and HFCs –join a global initiative to slow climate change impacts in the near-term, improve air quality, and enhance future food security. Business has the power to provide this much-needed rapid response.

Annies_sugarcane_field_courtesy.jpgTropospheric ozone is a gas formed by the interaction of sunlight with hydrocarbons, including methane, and nitrogen oxides, which come from power plants, automobiles and smokestacks. [10]  It is an extremely potent climate pollutant, forming above ground level to the top of the troposphere (about 10 kilometers). More than half of this dangerous climate pollutant is associated with the hydrocarbon, methane, so efforts to minimize methane are essential. However, a sizeable percentage of this pollution can also be addressed by tackling sources of other hydrocarbons and nitrogen oxides.  The transport and energy sectors are the chief areas where the food sector can make a big difference.  The added benefit to agriculture is that ozone at ground level has been shown to decrease crop yields [11], so efforts to reduce ozone can also benefit crops and profitability, as well as benefit farming communities from a human health standpoint).


What is expected of companies who commit to reducing short-lived climate pollutant emissions?

Companies will want to establish targets and a timeline, and commit to taking action at a significant scale relative to their operations in a short time span. Ample examples of improvements relative to each of the SLCPs exist.  Following the lead of global industry initiatives, for example, companies could commit to reducing HFCs by 30-50% within 10 years [13]. In addition, to ensure that their efforts can make a significant difference for the climate in the next decade companies may want to invest in selected results-oriented, low-cost projects affecting regional climate hot spots around the world, and participate in pilot efforts on new international climate accounting protocols.

To get started, companies may choose to engage with suppliers and partners to provide training, conduct pollutant inventories, establish systems for tracking, measuring and monitoring SLCP emissions.

A critical component of reducing SLCPs will be supporting the development of new technologies through advocacy and investment strategies. A number of local and global initiatives are seeking partners and financing to develop and launch new technologies such as no or low-emitting alternatives to HFCs or biogas projects at many scales from small to large. Companies might also consider investment in offsets to reduce methane such as investing in offsite projects that capture methane such as methane digesters on dairy farms.

Companies committing to reducing SLCPs will be expected to complete a short annual questionnaire updating the Climate Collaborative on progress made toward the commitment.

How can the Climate Collaborative Help? 

Our goal is to support businesses and stakeholders in the rapid reduction of SLCPs throughout the food production supply chain. We will facilitate networking, connect partners to initiatives and identify resources to help companies engage suppliers and support training efforts for tracking and measuring SLCPs.

We are planning webinars with partners and topic experts to help companies navigate the SLCP commitment while highlighting industry best practices, initiatives and financing options. Please let us know your needs and interests for reducing SLCPs in your supply chain to enable us to better focus our efforts.


Our Short-lived Climate Pollutants Resources page highlights case studies, videos, tools, and other resources from our partners to help organizations that are interested in reducing SLCPs – such as potent HFCs, black carbon and methane.

For those needing more tailored support, Sustainable Food Trade Association is available to help!