🌡️Intro to Climate Science Unit 15 – Climate Mitigation and Emission Reduction

Key Concepts and Terminology

• Greenhouse gases (GHGs) trap heat in the Earth's atmosphere, leading to global warming (carbon dioxide, methane, nitrous oxide, water vapor)
• Climate change refers to long-term shifts in temperature, precipitation patterns, and other climate variables caused by both natural and anthropogenic factors
  • Natural factors include variations in solar radiation, volcanic eruptions, and changes in Earth's orbit
  • Anthropogenic factors primarily involve greenhouse gas emissions from human activities (fossil fuel combustion, deforestation, agriculture)
• Climate mitigation aims to reduce the sources and enhance the sinks of greenhouse gases to limit the magnitude and rate of climate change
• Carbon footprint measures the total amount of greenhouse gases generated by an individual, organization, event, or product, expressed in carbon dioxide equivalents (CO2e)
• Renewable energy sources harness naturally replenishing resources (solar, wind, hydro, geothermal, biomass) to generate electricity or heat with lower GHG emissions compared to fossil fuels
• Energy efficiency involves using less energy to perform the same task or service, reducing energy consumption and associated emissions without compromising quality of life
• Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide in natural reservoirs (oceans, forests, soils) or through technological solutions (carbon capture and storage)

Causes of Climate Change

• Burning of fossil fuels (coal, oil, natural gas) releases carbon dioxide and other GHGs into the atmosphere, accounting for the majority of anthropogenic emissions
• Deforestation and land-use changes reduce the Earth's capacity to absorb carbon dioxide, as forests act as natural carbon sinks
  • Clearing land for agriculture, urbanization, or resource extraction contributes to GHG emissions and alters local and regional climate patterns
• Agricultural practices, such as livestock farming and rice cultivation, emit methane and nitrous oxide through enteric fermentation, manure management, and fertilizer use
• Industrial processes, including cement production, chemical manufacturing, and refrigeration, release GHGs as byproducts or through the use of fluorinated gases
• Waste management, particularly landfills and wastewater treatment, generates methane emissions from the decomposition of organic matter under anaerobic conditions
• Positive feedback loops amplify the warming effect, as rising temperatures trigger the release of additional GHGs from natural sources (permafrost thaw, ocean outgassing)
• Natural climate variability, such as El Niño and La Niña events, can influence global temperature and precipitation patterns on shorter timescales, but do not explain the long-term warming trend

Impacts of Greenhouse Gas Emissions

• Rising global temperatures lead to more frequent and intense heatwaves, droughts, and wildfires, affecting human health, agriculture, and ecosystems
• Sea level rise, caused by thermal expansion of oceans and melting of land-based ice, threatens coastal communities and infrastructure
  • Low-lying islands and coastal regions face increased risks of flooding, erosion, and saltwater intrusion into freshwater resources
• Changes in precipitation patterns, with some regions experiencing more intense rainfall and others facing prolonged droughts, disrupt water availability and agricultural productivity
• Ocean acidification, caused by the absorption of excess atmospheric CO2, harms marine life, particularly calcifying organisms (coral reefs, shellfish), and alters ocean food webs
• Biodiversity loss and ecosystem degradation occur as species struggle to adapt to changing climate conditions, leading to habitat loss, migration, and potential extinctions
• Human health is affected by increased exposure to extreme weather events, air pollution, and the spread of vector-borne diseases into new regions as temperatures rise
• Climate change exacerbates existing social and economic inequalities, disproportionately impacting vulnerable populations and developing countries with limited adaptive capacity

Climate Mitigation Strategies

• Transitioning to renewable energy sources (solar, wind, hydro, geothermal) reduces reliance on fossil fuels and associated GHG emissions
  • Increasing the share of renewables in the energy mix through supportive policies, investments, and technological advancements
• Improving energy efficiency in buildings, transportation, and industry minimizes energy consumption and emissions without compromising economic growth
  • Implementing building codes, appliance standards, and fuel efficiency regulations to drive efficiency improvements
• Promoting sustainable land management practices, such as reforestation, afforestation, and agroforestry, enhances carbon sequestration in terrestrial ecosystems
• Adopting low-carbon transportation options, including electric vehicles, public transit, and active mobility (cycling, walking), reduces emissions from the transportation sector
• Implementing carbon pricing mechanisms, such as carbon taxes or emissions trading systems, creates economic incentives for businesses and individuals to reduce their carbon footprint
• Encouraging sustainable consumption and production patterns, through education, awareness campaigns, and eco-labeling, to shift consumer behavior towards low-carbon alternatives
• Investing in research and development of negative emission technologies, such as direct air capture and bioenergy with carbon capture and storage (BECCS), to remove CO2 from the atmosphere

Emission Reduction Technologies

• Carbon capture and storage (CCS) technologies capture CO2 emissions from point sources (power plants, industrial facilities) and store them in underground geological formations or utilize them in industrial processes
• Energy storage solutions, such as batteries, pumped hydro, and hydrogen, enable the integration of variable renewable energy sources into the grid by balancing supply and demand
• Smart grid technologies optimize electricity distribution, reduce transmission losses, and facilitate the integration of distributed renewable energy generation
• Energy-efficient lighting, such as LED bulbs, consumes significantly less energy compared to traditional incandescent bulbs, reducing electricity consumption and associated emissions
• Advanced insulation materials and techniques, like aerogels and vacuum insulated panels, minimize heat transfer in buildings, reducing heating and cooling energy requirements
• Fuel cells convert chemical energy from hydrogen or other fuels into electricity, offering a clean and efficient alternative to combustion engines in transportation and stationary applications
• Carbon dioxide removal (CDR) technologies, such as direct air capture, enhanced weathering, and ocean fertilization, aim to remove CO2 directly from the atmosphere or oceans

Policy and Regulatory Frameworks

• The Paris Agreement, adopted in 2015, is a global treaty that aims to limit global warming to well below 2°C above pre-industrial levels and pursue efforts to limit the increase to 1.5°C
  • Countries submit Nationally Determined Contributions (NDCs) outlining their emission reduction targets and climate action plans
• Renewable energy mandates and portfolio standards require a certain percentage of electricity to be generated from renewable sources, driving the deployment of clean energy technologies
• Building codes and energy efficiency standards set minimum requirements for energy performance in new construction and renovations, promoting the adoption of energy-saving measures
• Carbon pricing policies, such as carbon taxes and emissions trading systems (ETS), assign a price to GHG emissions, creating a financial incentive to reduce emissions and invest in clean technologies
• Fossil fuel subsidy reform involves the phaseout of government support for fossil fuel production and consumption, leveling the playing field for clean energy alternatives
• Green public procurement policies prioritize the purchase of environmentally friendly goods and services by government agencies, stimulating demand for low-carbon products and technologies
• International climate finance mechanisms, such as the Green Climate Fund, provide financial resources to support mitigation and adaptation efforts in developing countries

Economic Implications

• The transition to a low-carbon economy requires significant investments in clean energy infrastructure, energy efficiency, and sustainable land use practices
  • Upfront costs can be offset by long-term savings from reduced energy consumption and avoided climate change impacts
• Climate change impacts, such as extreme weather events and sea level rise, impose substantial economic costs through damage to infrastructure, disruption of supply chains, and reduced agricultural productivity
• Carbon pricing can generate revenue for governments, which can be used to support low-carbon investments, assist affected communities, or reduce other taxes (revenue recycling)
• The development and deployment of clean technologies create new business opportunities and jobs in sectors such as renewable energy, energy efficiency, and sustainable transportation
• Stranded assets, particularly in the fossil fuel industry, may occur as the world shifts away from carbon-intensive investments, potentially leading to financial losses for investors
• Climate change adaptation measures, such as infrastructure upgrades and disaster risk management, require substantial funding but can help minimize the economic impacts of climate-related disasters
• International trade and competitiveness concerns arise as countries implement different levels of climate policies, potentially leading to carbon leakage and calls for border carbon adjustments

Challenges and Future Outlook

• Political and social resistance to climate action persists, often driven by vested interests, short-term thinking, and unequal distribution of costs and benefits
• Technological barriers, such as the intermittency of renewable energy sources and the need for large-scale energy storage, require further research and development to overcome
• Behavioral change and public acceptance of low-carbon lifestyles and technologies are crucial for the success of mitigation efforts but can be challenging to achieve
• Equity and justice considerations must be addressed to ensure that the costs and benefits of the low-carbon transition are distributed fairly within and between countries
• Climate change is a global problem that requires international cooperation and coordination, but national interests and differences in capabilities and responsibilities can hinder collective action
• Tipping points and irreversible impacts, such as the melting of the Greenland ice sheet or the collapse of the Amazon rainforest, could accelerate climate change and limit the effectiveness of mitigation efforts
• Adaptation and resilience-building efforts will be necessary to cope with the impacts of climate change that are already locked in due to past and current emissions, even as mitigation efforts aim to limit future warming