causality ppt

___** Data (Before Thermometers)

Used to reconstruct temperatures for >800,000 years:

• Ice ___ (air ___ show ancient _____; ____ ratios show ___)

• ___ rings

• ___

• ___

proxy, cores, bubbles, CO2, isotope, temperature, tree, sediments, corals

C. Volcanic Activity

Volcanoes eject:

• ___ → ____ effect by reflecting sunlight.

• CO₂ → heating effect, but far less than humans emit.

Modern warming is far too large & fast to be volcanic.

aerosols, cooling

5. Greenhouse Effect – Natural vs. Enhanced

Natural Greenhouse Effect

• ___ warms Earth → some heat radiates back to space

• Certain gases trap heat (CO₂, CH₄, N₂O, water vapor)

• Without this, Earth would be ~33°C colder

Enhanced Greenhouse Effect

• Human emissions increase greenhouse gases

• More trapping of ___ infrared heat

• Planet warms rapidly

sunlight, longwave

Key Greenhouse Gases (GHGs)

1. CO₂ – carbon dioxide

2. CH₄ – methane

3. N₂O – nitrous oxide

4. Water vapor (positive feedback, not driver)

5. Ozone (O₃)

CFCs & HFCs (___ gases, very powerful)

industrial

Important Concept: Radiative ___

• Measure of how much a ___ (CO₂, sun, aerosols) ____ Earth’s energy balance ___ or down (warming or cooling).

• Positive RF = warming

• Negative RF = cooling

Human-caused CO₂ is the largest positive radiative forcing.

forcing, factor, pushes, up

6. Carbon Cycle & Human Disruption

Natural Carbon Cycle

CO₂ ___ between:

• Atmosphere

• Oceans

• ___

• Soil

• ___

Balances over long timescales.

moves rocks plants

natural carbon cycle

Human Impacts

• Burning fossil fuels (coal, oil, gas)

• Deforestation → removes carbon sinks

• Industrial processes (___ production)

Result: CO₂ skyrocketed from ~280 ppm (pre-industrial) to >420 ppm today
— highest in at least 800,000 years (ice core data).

cement

7. How Scientists Know Warming Is Human-Caused (Attribution Science)

Fingerprint Evidence

Warming caused by GHGs has unique patterns.
All are observed:

Troposphere ___ while ___ cools
→ caused by GHGs, NOT the Sun.

warms, stratosphere

fingerprint evidence Nights warm faster than days
→ trapped heat, not more incoming sunlight.

1. ___ warm faster than summers
   → greenhouse effect, not solar forcing.

2. Arctic warms fastest (Arctic amplification)
   → ice–albedo feedback from warming.

More heat stored in the ___, not just air
→ matches GHG models.

winters, ocean

B. Water Vapor Feedback

• Warming → more __ → more water vapor

• Water vapor = potent greenhouse gas

• Causes more warming

evaporation

9. Climate Models

What models include:

• Physics of ___ & oceans

• Greenhouse gas levels

• Solar + ___ effects

• Land use

• Aerosols

Only models with human-caused GHGs reproduce observed warming.
Without humans, models show near-flat warming or slight cooling.

atmosphere, volcanic

Characteristics of the Anthropocene:

• Dominance of ___ activity on Earth systems

• Rapid increase in:

  • CO₂ + other ___

  • __ rates

  • Resource ___ (land, water)

  • ____ & land use change

• Climate conditions leaving Holocene stability

human, GHGs, extinction, extraction, urbanization

anthropocene human driven Consequences:

• Increased ____ weather

• ___

• Flooding

• Sea-level rise

• Drought

• ___ loss

• Food & water insecurity

extreme, heatwaves, biodiversity

Fingerprint evidence confirms human __.

causation