Methane & Other Gases🔗

Decrease or increase greenhouse gas emissions from methane, nitrous oxide, and the F-gases. Methane (CH₄) is released from sources like cows, agriculture, oil and natural gas drilling, and waste. Nitrous oxide (N₂O) mainly comes from fertilizers. Fluorinated gases, or F-gases, include HFCs, PFCs, and others that are used in industry and consumer goods like air conditioners.

Examples🔗

• Decreased meat consumption, which reduces emissions from livestock and the fertilizers used to produce livestock feed.
• Modified agricultural practices such as better processing of manure and decreasing fertilizer use.
• Decreased methane leakage from oil and gas industries, for example by reducing venting and flaring of methane from oil and gas wells and properly sealing old wells.
• Increased capturing of gases emitted from landfills.
• Research and development into substitutions for F-gases in industrial processes and consumer appliances.

Big Messages🔗

• Reducing methane, nitrous oxide, and the F-gases is high leverage, although many approaches to reducing these emissions need more research and support to scale up.

Key Dynamics🔗

• Methane, N₂O, and F-gas emissions comprise approximately 30% of current greenhouse gas emissions, and their reduction is key to addressing climate change.

Potential Co-Benefits of Decreasing Methane & Other Gases🔗

• Plant-based diets have been shown to be healthier for individuals and have less impact on ecosystems.
• Sustainable and plant-based agriculture produces more food with fewer resources, which increases food security.
• Reducing methane leakage from natural gas systems can save money.
• Less nitrogen-rich fertilizer runoff can reduce water pollution, decrease eutrophication, and increase the health of ocean ecosystems.

Equity Considerations🔗

• Many cultural values are attached to certain foods, meaning a change to more plant-based diets could require a large societal shift.
• Policies implemented without care may threaten food security for certain individuals and communities. For example, rice paddies, a large methane contributor, produce a main dietary staple for many countries.
• Changes in agricultural practices can threaten local economies and employment in communities that rely on industrial, large-scale farming practices as their main livelihood.

Videos🔗

Methane & Other Gases

Slider Settings🔗

The variable being changed is the percent reduction or percent increase of maximum possible action. The model limits how much these emissions can be reduced—so 100% max reduction is not a 100% total emissions reduction—since some emissions are considered unavoidable, particularly a minimum amount of emissions from agriculture, landfills, and wastewater. The lower limit is approximated from the agriculture and waste emissions in IPCC scenarios for RF 1.9 levels for land use.

Slider settings for modeling food system changes in En-ROADS:

To test out changes to the food and agriculture system in En-ROADS, use a combination of three sliders according to the table below. The “Agricultural and waste emissions” slider, located in the advanced settings of Methane & Other Gases, adjusts the direct emissions from livestock and fertilizer use. The food system is linked to other sectors, so also adjust the Transport Energy Efficiency (representing reduced need for farm machinery, transport, etc.) and Deforestation sliders (representing decreased demand for grazing land). Pick only one Livestock or Diet column—these are alternative choices, they do not add together.

The Improved Crop System settings can be used alone or in combination with any of the other options. These represent agricultural practices that grow food with less land and emissions, including improved seed quality or crop varieties, crop rotation, efficient methods of fertilization, and irrigation.

Add the settings to your current scenario. Note that the Agricultural & Waste and Deforestation slider values are negative (lower emissions) while the Transportation slider is positive (more progress). For more information, see “How to talk about food in En-ROADS.”

These slider settings are based on the UN Food and Agriculture Organization (FAO) report Tackling Climate Change with Livestock (2013).

Assumptions behind these settings:

(a): 1/3 reduction of each category of associated emissions
(b): 1/3 of energy and deforestation emissions plus 2/3 of direct emissions

Model Structure🔗

Each greenhouse gas is modeled separately within En-ROADS, which enables the impact of each gas on global temperature to be handled without using global warming potential (GWP) and CO₂ equivalency conversions. Greenhouse gases other than CO₂ that are reflected in graphs with the units CO₂e do use GWP100 to enable comparison and reporting of all greenhouse gases together. This means that the short-lived, but high impact, nature of greenhouse gases like methane is captured.

Case Studies🔗

Carrboro, NC, USA: Participation in a community gardening program in Carrboro, NC showed improvements in childhood obesity levels and resulted in families with children in the program eating one-third more fruits and vegetables every day.¹

FAQs🔗

• How do I simulate plant-based, vegetarian, or vegan diets?

Please visit support.climateinteractive.org for additional inquiries and support.

Footnotes

[1]: Castro, D. C., Samuels, M., & Harman, A. E. (2013). Growing Healthy Kids. American Journal of Preventive Medicine, 44(3).