Key Topic 3: Greenhouse-gases (GHG)

This section Greenhouse-gases (GHG) will describe and explain you the seven greenhouse gases, their sources and effects. Also, you will find out what the concepts of carbon footprint and carbon credits mean, and will learn about the European Union plan on reducing greenhouse gases. 

Major greenhouse gases and their sources

• 1. Carbon dioxide (CO₂): is the primary greenhouse gas, responsible for about 3/4 of emissions. It can linger in the atmosphere for thousands of years. Sources: mainly from burning organic materials (coal, oil, gas, wood, and solid waste).
• 2. Methane (CH₄): is the main component of natural gas. A molecule of methane doesn’t stay in the atmosphere as long as a molecule of carbon dioxide – about 12 years – but it is at least 84 times more potent over two decades. It accounts for about 16% of all greenhouse gas emissions.

Sources: it is released from landfills, natural gas and petroleum industries, and agriculture (especially from the digestive systems of grazing animals)

• 3. Nitrous Oxide (N₂O): Nitrous oxide occupies a relatively small share of global greenhouse gas emissions – about 6%- but it is 264 times more powerful than carbon dioxide over 20 years, and its lifetime in the atmosphere exceeds a century, according to the Intergovernmental Panel on Climate Change (IPCC). 

Sources: agriculture and livestock, including fertilizer, manure, and burning of agricultural residues, along with burning fuel.

• 4. Fluorinated gases (hydrofluorocarbons, perfluorocarbons, chlorofluorocarbons, sulfur hexafluoride (SF₆), nitrogen trifluoride (NF₃)) have heat-trapping potential thousands of times greater than CO₂ and stay in the atmosphere for hundreds to thousands of years. They account for about 2% of all emissions.

Sources: they are used as refrigerants, solvents, and in manufacturing, sometimes occurring as byproducts.

• 5. Ground-Level Ozone: besides trapping heat, ground-level ozone is a pollutant that can cause respiratory health problems and damage crops and ecosystems.
• Sources: chemical reactions between nitrogen oxides and volatile organic compounds from automobiles, power plants, and other industrial/commercial sources in the sunlight presence. 
• 6. Water Vapor: have key role in climate feedbacks because of its heat-trapping ability (warmer air holds more moisture than cooler air). 

Sources: as GHG concentrations increase and global temperatures rise, the amount of water vapor in the atmosphere increases, amplifying the warming effect. Unlike other GHG, water vapor condense and rain out when it reaches high concentrations. While human activities do release water vapor into the air, these activities have been determined to have a negligible effect on global climate.

• 7. Aerosols:  microscopic (solid or liquid) particles that are so small that instead of quickly falling to the surface like larger particles, they remain suspended in the air for days to weeks. Unlike greenhouse gases, the climate effects of aerosols vary depending on what they are made of and where they are emitted. Depending on their color and other factors, aerosols can either absorb or reflect sunlight. Aerosols that reflect sunlight (e.g. particles from volcanic eruptions or sulfur emissions from burning coal) have a cooling effect, those that absorb sunlight (black carbon – a part of soot), have a warming effect.

Sources: human activities, such as burning fossil fuels and biomass, contribute to emissions of these substances, although some aerosols also come from natural sources such as volcanoes and marine plankton.

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Effects of GHG

• GHG have far-ranging environmental and health effects. 

• GHG cause climate change (or global warming) by trapping heat, and they also contribute to respiratory disease from smog and air pollution. Extreme weather, food supply disruptions, and increased wildfires are other effects of climate change caused by GHG. The typical weather patterns we’ve grown to expect will change; some species will disappear; others will migrate or grow.

Carbon footprint

• The carbon footprint is “the sum total of all the greenhouse gas emissions that had to take place in order for a product to be produced or for an activity to take place.” (Berners-Lee, 2020)
• Products and activities that produce carbon footprint: 

household energy use 

transport 

food 

everything else

• A person’s carbon footprint is the combined total of the products they buy and use, the activities they undertake.
• Unsurprisingly, in general terms the size of a person’s carbon footprint tends to increase with wealth.
• Carbon footprint calculators: from the Nature Conservancy; from the United States Environmental Protection Agency

Carbon credits

• Carbon credits are tradable instruments (typically a virtual certificate) that convey a claim to avoided greenhouse gas (GHG) emissions or enhanced GHG removals.

1 Carbon Credit = one tone of carbon dioxide equivalent (𝐶𝑂₂𝑒 )

(a single carbon credit is equivalent to the removal or avoidance of one tone of carbon dioxide or its equivalent in other greenhouse gases). 

• Carbon credits are generated by projects like renewable energy or reforestation, and companies buy them to offset their own emissions and support climate action. 
• Once a credit is purchased and retired, it ensures the reduction is permanent and cannot be reused. 

• Watch this video: ClimateChange_CarbonCredits_CarbonOffsetingProjects 
• Read here: Carbon Offset Guide

GHG reduction strategies

Read here: 

https://ghgreduction.eu/; https://www.epa.gov/climateleadership/ghg-reduction-programs-strategies ; 3-actions-essentielles-pour-reduire-les-emissions-de-ges/

Case Study

Title: Accelerating decarbonization across the farming supply chain

• Overview: Agriculture equipment manufacturer AGCO worked with McKinsey to automate decarbonization cost curve building and planning efforts, using the Catalyst Zero tool.

Case Study: Accelerating decarbonization across the farming supply chain

THE OPPORTUNITY: Reducing farming’s carbon footprint

• AGCO Corporation, a global leader in the design, manufacture and distribution of agricultural machinery and precision ag technology, operates manufacturing sites across Europe, Asia, South America, and the US, selling under the Fendt, Massey Ferguson, and Valtra brands. The global company is on a mission to revolutionize farming and significantly cut down its environmental footprint, with ambitious goals to slash its Scope 1 and 2 emissions 55% by 2033 and 90% by 2050.
• “The agriculture industry is a key part of the solution to combatting climate change,” says AGCO Senior Vice President, General Counsel, Chief ESG Officer, and Corporate Secretary Roger Batkin. “We’ve committed to bringing smart solutions to our farmer customers to increase sustainable agricultural practices across the globe.”
• To address these challenges, AGCO has utilized Catalyst Zero, McKinsey’s end-to-end decarbonization tool that identifies cost-effective options to reduce carbon emissions. AGCO collaborated with the Catalyst Zero team to create an integrated and automated version of its Marginal Abatement Cost Curve (MACC) generator, which compares the cost and emissions impact of different traditional and tech-enabled abatement strategies.

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THE SOLUTION: Transparent carbon accounting powered by AI

• To streamline this process and address challenges more systemically, Catalyst Zero partnered with Amazon Web Services (AWS), AGCO’s existing cloud solutions platform. McKinsey and AWS worked together to build and put in place Catalyst Zero’s latest MACC capability, which solves the challenge of often messy and inconsistently formatted raw data coming in.
• Using machine learning, advanced analytics, and AI, Catalyst Zero reduces the time and cost to build or update MACCs by up to 90%. It works by processing 300,000 emissions data points from multiple Enterprise Resource Planning (ERP) systems with minimal manual intervention.
•  “The only way companies are really going to abate carbon is to know exactly where it’s coming from and be able to account for it. We’re helping AGCO […] selecting the most impactful and financially viable decarbonization levers”, says McKinsey Partner Eric Hannon.
• Catalyst Zero’s web-based interface offers easy access to baseline carbon data, granular MACCs, and detailed insights into decarbonization levers. Powered by machine learning, it automatically converts raw data from AGCO’s ERP systems into actionable decarbonization initiatives or precise emission data.

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THE IMPACT: A more strategic and efficient decarbonization process

• AGCO’s use of Catalyst Zero is both improving the accuracy of emissions baselining and decarbonization analytics and greatly accelerating the process. Using the Catalyst Zero tool, AGCO can obtain insights in just one week, significantly cutting down on the previous eight-week process.
• In addition to improving operational efficiency and sustainability reporting, this is also enhancing strategic decision-making. By deepening its understanding of decarbonization strategy across various business units and regions, AGCO will be able to execute these initiatives more cost-efficiently. For example, the tool is helping identify a 10% reduction in costs associated with reaching AGCO’s decarbonization target.
• In tandem, AGCO is focusing on implementing key decarbonization initiatives, such as transitioning to electrified tractors and identifying tech-enabled levers to reduce Scope 3 emissions in its supply chain.

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Case Study Relevance

• This Case Study is highly relevant to Sustainability Science as it demonstrates how the integration of innovative technology can accelerate evidence-based decision-making for climate action. By reducing the time and cost required to build or update Marginal Abatement Cost Curves (MACCs), the company was able to more efficiently identify and prioritize cost-effective carbon reduction opportunities. This technological approach not only enhances the company’s operational sustainability but also contributes to the broader scientific understanding of how data-driven innovation can optimize decarbonization pathways. 
• This is a real example of good practice, on how to act faster and, thus, promptly align the pace of intervention to reduce the carbon footprint, to the speed with which carbon emissions and their negative effects are produced. 
• Ultimately, the Case Study exemplifies how digital transformation can be leveraged to bridge the gap between economic efficiency and environmental responsibility, driving tangible progress toward carbon neutrality.

Case Study Questions

• Question 1: How does the integration of AI, machine learning, and advanced analytics accelerate a company’s decarbonization journey compared to traditional methods?
• Question 2: In what ways can emerging technologies support sustainability beyond carbon reduction – for example, in water use, biodiversity, or waste management?
• Question 3: What are potential risks or ethical considerations of relying heavily on AI for sustainability decisions?
• Question 3: How can companies ensure that technological innovation aligns with their broader sustainability and social responsibility goals?
• Question 5: What role do you think future professionals – like you – can play in integrating digital innovation with environmental stewardship?