Air

Atmospheric Sciences and Pollution

Layers of the Atmosphere

• Exosphere

  • 1200°C

  • 800 to 3000 km

• Thermosphere

  • -86.5 to 1200°C

  • 80-900 to 900 km

• Mesosphere

  • -2.5 to -86.5°C

  • 40-50 to 80-90 km

• Stratosphere

  • -56.5 to -2.5°C

  • 11 to 50 km

• Ozone Layer

  • Ozone is formed when ultraviolet radiation interacts with nitrogen oxides (NOx) and volatile organic compounds (VOCs

• Troposphere

  • 15 to -56.5°C

  • 0 to 12-18 km

  • The air is densest in this lowest layer.

  • Troposphere contains 75% of the mass of the entire atmosphere.

  • Composition: 78% nitrogen, 21% oxygen, 1% argon, water vapor, and carbon dioxide.

Early Days

• Cyanobacteria

  • 1st bacteria formed the atmosphere with a few microscopic organisms.

  • A single-celled organism that can produce oxygen.

• Stromatolites

  • Fossilized remains of microbial mats that enriched the atmosphere, leading to the development of plants.

• Scale trees successfully converted carbon dioxide into oxygen, contributing to the ice age at the end of the Carboniferous period before they went extinct.

• Earth's atmosphere has changed over geological periods through natural processes such as fires and earthquakes.

• Natural sources continue, but humans have added many other sources, including:

  • Industrialization

    • Hollywood movies: 391-3,370 metric tons of CO2.

    • War (e.g., Kuwait: 1,000 oil well fires burning 5-6 million barrels of crude oil a day).

  • Ozone Formation

    • Ultraviolet radiation + nitrogen oxides + volatile compounds = ozone.

  • Heavy Metal Extraction

    • Heavy metal ores in sulfide minerals extracted for centuries; the earth naturally sequesters toxic metals in association with volcanic systems and coal.

  • Lead Contamination

    • Contamination began due to natural processes thousands of years ago.

  • Global Mercury Sources

    • Biggest source: artisanal and small-scale gold mining, with spikes from events such as Mt. St. Helens, WW2 manufacturing, gold rush era, and Tambora eruption.

Food System

• Bioaccumulation and Biomagnification of mercury in fish

• Pollution in the food system.

Acids

• What comes up, eventually comes down.

• Coal and Fertilizers

  • Coal typically contains 1-2% nitrogen and 2-6% sulfur.

  • Issues with acid rain damaging or killing plant life and buildings.

Emissions Standards

• Technology to Reduce Emissions

  • Capture sulfur before it leaves the power plant: sulfur scrubber.

Nuclear Power

• Chernobyl

  • Radioactive fallout led to zoned-off areas, expanded beyond the original 30 km radius as pollution spread.

• Nuclear Testing in the Marshall Islands.

Emerging Contaminants

• Atmospheric Microplastics

• Global Plastic Production

• Forever Chemicals:

  • Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are synthetic chemicals resistant to heat, grease, water, and oil.

Climate Change and Sea Level Rise

The Greenhouse Effect

• Greenhouse gases get trapped in the troposphere.

• Sunlight is reflected back to space, absorbed by Earth's surface, and then some is reflected by surface.

• Human activities release greenhouse gases, trapping heat from the sun.

The Carbon Cycle

• Carbon enters the atmosphere as CO2, absorbed by autotrophs (green plants).

• Animals consume plants, incorporating carbon.

• Death and decomposition of plants and animals reabsorb carbon into the atmosphere.

• This cycle ensures that carbon is continuously recycled, maintaining the balance of ecosystems and supporting life on Earth.

Global Temperatures

• Global temperatures are constantly rising.

• 2023 is the warmest year on record, and 2024 is on track to be warmer.

• 2015-2024: The warmest 10-year period on record.

• Global greenhouse emissions returned above pre-pandemic levels, rising across all sectors in 2021.

Temperature and CO2

• Temperature does not react instantly to each year’s record high CO2 levels due to the high heat capacity of oceans and other natural factors.

Sea Ice

• Volume of Arctic sea ice is decreasing.

• Melting sea ice doesn't directly cause sea level rise but warms near polar masses.

• Albedo Effect: Water absorbs ~93% and reflects ~7%; ice/snow absorbs ~15% and reflects ~85%.

• Contributing factors to sea level rise:

  • Melting glaciers (45%)

  • Thermal expansion (38%)

  • Melting Antarctic ice sheet (13%)

  • Ice loss from Greenland (4%)

• Rapid melting in some parts of Antarctica, while other areas are gaining ice due to heavy snowfall (20 cm per year).

• Projected sea level rise:

  • East Coast: 10-14 inches

  • West Coast: 4-8 inches

  • Gulf Coast: 14-18 inches

  • By 2100: 0.63-1.60 m (2-5 ft)

  • By 2150: 0.98-4.82 m (3-16 ft).

• Complete ice melt would raise global sea levels by approximately 70 m (230 ft), flooding coastal cities.

• Local factors like isostatic rebound can make sea levels appear to go down in some areas.

Environmental Impacts

• Loss of top predators in the Arctic.

• Desynchronization of migration and food availability.

• Krill: Juvenile krill depend on sea ice; significant in the biosphere as the food chain base in the Southern Ocean, especially Antarctica.

• Ocean Acidification: Affects forams, corals, shellfish, etc.

• Coral Bleaching: Zooxanthellae leave coral tissue, disrupting mutualistic relationships.

Reducing Emissions

• 350 ppm is the safe upper limit for CO2 in the atmosphere.

• To reduce CO2 below 350 ppm, focus on drastically reducing fossil fuel emissions and implementing renewable energy sources.

• Emerging technologies like direct air capture with carbon storage (DACCS) exist but are not widely used due to high costs.

Merchants of Doubt Video

• Explores climate change consensus and myths.

• Highlights issues like cigarettes (corporate interests).

• Claims of climate scientists having political agendas; attempts to distort scientific information concerning climate change.

Air Pollution Policy

Main Ideas and Questions

• What is the Clean Air Act?

• What are the impacts of the Clean Air Act?

• What is the Montreal Protocol?

• How does the Clean Air Act impact climate change?

• What is the denial machine?

• What US policies have sought to address climate change?

The Clean Air Act

• Regulates emissions from stationary and mobile sources.

• Regulates six criteria air pollutants:

  • Sulfur dioxide

  • Nitrogen dioxide

  • Carbon monoxide

  • Particulate matter 2.5

  • Ground level ozone

  • Lead

Goals

1. Reduce ambient concentrations of air pollutants causing smog, haze, and acid rain.

2. Reduce emissions of toxic air pollutants known to cause serious health effects.

3. Phase out production and use of chemicals damaging the stratospheric ozone.

Sources of Emissions

• Industrial and other processes

• Stationary fuel combustion

• Non-road mobile sources

• Highway vehicles

Costs and Benefits of Clean Air Act

• Costs: $65 billion; Benefits: $2 trillion.

• Pollution impacts unevenly; Black and Hispanic communities have less pollution contribution, yet are exposed to more than others.

Ozone and the Montreal Protocol

• CFCs in refrigerators damage the ozone layer.

• 2024: Antarctica ozone hole ranks 7th smallest since the recovery began.

• Montreal Protocol: International agreement to protect the ozone layer by phasing out ozone-depleting substances (ODS).

Climate Change Policy

What the World Thinks

• About 50% of people think about climate change on a weekly basis.

• If you live in a country that is a high CO2 emitter, you are less concerned about climate change.

• 80% of people are willing to change how they live to help combat climate change.

Carbon Map Exercise

• Question: Why do higher percentages of people in poorer countries see climate change as a problem that will affect them personally?

• Answer: Because they are more vulnerable to climate change.

Climate Governance

• 1988: Intergovernmental Panel on Climate Change established.

• 1990: IPCC report confirms existence of anthropogenically driven global warming.

• 1992: Earth Summit in Rio de Janeiro.

• 1995: IPCC second assessment report concludes humans are discernibly influencing global climate.

• 1997: Adoption of the Kyoto Protocol to the UN Climate Convention.

• 2002: IPCC third assessment.

• 2007: IPCC fourth assessment.

• Bali: Global call for more "measurable, reportable, and verifiable" nationally appropriate mitigation strategies.

• 2009: Copenhagen Accord.

  • Goals in Brief:

    • Acknowledge deep cuts in GHG emissions necessary to hold global temperature increases below 2 degrees Celsius.

    • Set deadlines for countries to submit emissions limitation pledges.

    • Called for developing countries to increase frequency of reporting.

    • Recognizes critical role of reducing emissions from deforestation and forest degradation.

    • Calls for technology developments and transfer mechanisms.

  • Problems:

    • Accord is not legally binding.

    • Negotiation process only included 28 countries.

    • If countries only put forward emissions targets brought to Copenhagen, global temperature increases will still exceed 2 degrees.

  • Ecological Debt: Recognizing individual countries' political, cultural, and economic differences; the powerful and powerless in global negotiations.

• 2010: Cancun.

  • Advanced countries formally agree to mobilize US$100 billion a year by 2020 for the mitigation and adaptation needs of developing countries.

  • By 2020: pledges and commitments totaled $18.54 billion.

• 2011: Kyoto Protocol extended.

• 2015: Paris Climate Accord signed.

  • Objective: To achieve a binding and universal agreement on climate from all nations of the world.

  • What Countries Offered: Intended nationally determined contributions (INDCs); each country makes a contribution based upon its own needs and abilities.

  • Progress to Date:

    • By 2017, every country signed the agreement (184 countries signed on).

    • Everything is voluntary; even if goals were met, they could not be enough.

  • Key Events:

    • 2017: US withdraws from Paris Climate Accord.

    • 2021: US rejoins Paris Accord.

    • COP26: New pages deemed too weak, targeted at 1.5 degrees.

    • COP29: Recently concluded, noted for proposed changes to all aspects of society.

Kyoto Protocol

• An international treaty that set legally binding targets to reduce greenhouse gas emissions.

• Industrialized and transition countries to reduce overall emissions by 5% below 1990 levels by 2012.

• Emissions Trading: Countries may buy and sell greenhouse gas emissions units and credits.

• Clean Development Mechanism: Provides a system for financing emissions-reducing or avoiding projects in developing countries.

• Joint Implementation Strategies: Industrialized countries are granted emissions reductions units for financing projects in other developed countries.

• 1997: Adoption of the protocol.

• 2001: Rules for implementation agreed upon.

• 2005: Protocol is implemented; 191 countries signed and ratified.

  • US: Signed but did not ratify.

  • Canada: Signed but withdrew from the agreement in 2012.

Key Interests of Industry

• Coal, oil.

Shared Socioeconomic Pathways (SSPs)

• SSP1: Sustainability - Low challenges to mitigation and adaptation.

• SSP2: Middle of the road - Medium challenges to mitigation and adaptation.

• SSP3: Regional rivalry - High challenges to mitigation and adaptation.

• SSP4: Inequality - Low challenges to mitigation, high challenges to adaptation.

• SSP5: Fossil-fueled development - High challenges to mitigation and adaptation.

History of Climate Policy

• 1992: Rio Earth Summit with Ronald Reagan concerning climate agreements.

• 1993: BTU Tax based on heat units emitted from burning carbon fuels.

• 1995: Campaign to Create Doubt regarding climate change.

• 1997: Kyoto Protocol to set legally binding CO2 limits.

• Bush Era Climate Action: Climate action calls and greenhouse gas emission limitations.

The Clean Air Act and Climate Change

• 2006: Massachusetts vs. EPA Supreme Court case defining greenhouse gases as air pollutants.

• 2009: EPA declares six GHGs harmful to public health.

• 2010: EPA begins regulation of GHGs.

• 2011: Increase Corporate Average Fuel Economy (CAFE) to 54.5 mpg by 2025.

• 2014: Clean Power Plan to reduce CO2 emissions by 32% by 2030.

The Denial Machine

• Beliefs, doubts, and political attitudes towards climate change.

Recent Climate Policies

• Inflation Reduction Act and the Infrastructure Investment and Jobs Act: Aim to lower costs for families, create fairness in tax codes, and tackle the climate crisis (e.g., tax rebates for electric vehicle purchases).

History of/in the Climate Crisis

Historical Perspective on Climate Change

• Climate change inherently involves a historical perspective that helps us understand the scope and scale of the problem.

• Most of human civilization developed in a temperate climate, around 280 ppm of CO2.

• Earth's mean temperature has risen more than half a degree Celsius since 1950.

• The Ruddiman (Early Anthropocene) hypothesis argues that human activity, specifically deforestation and agriculture, has produced enough CO2 and methane to significantly warm the atmosphere and prevent a new ice age. Recent studies support at least the main ideas of this hypothesis.

Old Climate Patterns

• Climate Change as a Historical Constant: While climate change itself is not new, what is new is that humans have become the driving force behind it.

• Temperature Trends: Current temperatures are 0.3-0.1 °C higher than those from 1960-90 in the Northern Hemisphere, with effects being unevenly distributed.

Climatic Phases

• Medieval Land Period:

  • Increased land devoted to agriculture.

  • Population in Europe increased by 50%.

  • Strengthened economies.

  • Vikings navigated to Greenland due to less ice in the Atlantic.

• The Little Ice Age:

  • Climatic phase overlapping with late medieval and early modern periods.

  • Associated with economic depression, wars, and famine.

  • Colder periods allowed for events like Dutch canals freezing over for ice skating and Frost Fairs on the Thames River.

  • Causes include: solar energy fluctuations, volcanic eruptions reducing solar radiation, and shifts in ocean currents.

Impact of American Colonization

• Columbian Exchange:

  • Introduced new diseases with huge demographic impacts and population collapse.

  • Estimates suggest European arrival in 1492 led to 56 million deaths by 1600.

  • A significant population reduction led to reforestation.

  • The 1610 atmospheric CO2 drop was partly attributed to indigenous depopulation of the Americas, with global atmospheric CO2 falling by 7-10 ppm during the late 1500s and early 1600s.

Driving Forces of Climate Change

• Anthropocene:

  • Began with events in Great Britain during the late 18th and early 19th centuries.

  • Age of industrialization shifted the economy from organic to fossil, leading to the burning of fossil fuels like coal, oil, and gas.

• Coalification:

  • Peats are buried and transformed into coal through compaction and heating over time.

  • Increased use of coal significantly contributes to emissions.

• The Biological Old Regime:

  • All energy derived from the sun through photosynthesis, with shifts in energy sources.

  • Before the steam engine, English textile mills utilized water power.

• Technological Developments:

  • In the 1820s, Robert Tom developed hydraulic systems targeting the unreliability of water power.

  • The invention of the steam engine led to widespread industrial applications, especially in textile production.

• Sociogenic Global Warming:

  • Resulted from English capitalists exploiting coal fields for steam power utilization in production.

  • Emissions from burning coal dramatically increased, contributing to global warming alongside farming and livestock raising.

The Great Acceleration

• Globalization Post-WWII:

  • Rapid increase in global economic production and population post-1945.

  • An estimated three-quarters of human-caused CO2 accumulation occurred after WWII.

  • This led to unprecedented ecological changes and is described as the sixth mass extinction due to unsustainable resource consumption.

  • Major contributors to deforestation include palm oil production.

Notable Figures and Studies

• Guy Callendar:

  • Early recognition of CO2 effects on warming; thought global warming would alleviate glacier conditions and benefit crop growth at higher latitudes.

• Cold War Influence:

  • The rise of atmospheric science, notably during the space race and atomic testing; critical studies emerged indicating human contributions to carbon emissions.

• The Keeling Curve:

  • Represents atmospheric carbon dioxide concentrations since 1958, showing annual cycles of CO2 fluctuation influenced by plant activity.

Environmental Movement and Policy**

• Clean Air Act:

  • In the 50s and 60s, environmental concerns reached high levels in US government.

  • President Lyndon Johnson highlighted rising CO2 levels as a pressing issue.

  • Various organizations investigated climate change influences, with oil companies like Exxon becoming involved.

Summary

The history of climate change illustrates how human activities from agriculture to industrialization have shaped our climate. Understanding these historical dimensions is critical for comprehending the challenges we face today as we navigate the climate crisis.

Signs of Hope in the Climate Crisis

• Strong reductions in emissions could limit climate change; CO2 emissions plunged 4.6% in 2020.

• South Australia: Renewable energy transformation.

• China: Leading in renewable energy installations, doubling solar capacity in 2023.

• Green New Deal: Aiming to mitigate the climate crisis while creating jobs.

• California aims for a 40% emissions reduction below 1990 levels by 2030, reflecting indigenous resistance to climate impacts.