Meterology 1347 Final Exam Ch 12-14

Climatic Controls

Intensity of sunshine, land/water distribution, ocean currents, prevailing winds, pressure areas, mountain barriers, altitude.

Purpose of Studying Past Climates

To understand natural variability, drivers of change, and assess model accuracy.

Climate Evidence

Instrumental records and geological proxies (e.g., ice cores, tree rings).

Ice Cores

Show past temperatures via oxygen isotopes and greenhouse gases via trapped air bubbles.

Tree Rings

Reveal past soil moisture and temperature conditions.

Climate Change Drivers

Natural (solar radiation, surface type, atmospheric composition, feedbacks) and anthropogenic (GHGs, land use).

Milankovitch Cycles

Include eccentricity, obliquity, and precession; affect solar energy distribution.

Surface Change & Albedo

Changes in land cover or continental positions alter albedo and climate.

Aerosols vs. GHGs

Aerosols cool by scattering sunlight; GHGs trap infrared radiation and warm the climate.

Feedback Mechanisms

Positive: amplifies warming; Negative: dampens it.

Water Vapor Feedback

Warming increases water vapor, which strengthens greenhouse effect.

Snow-Albedo Feedback

Melting snow reduces albedo, increasing solar absorption and warming.

Planck Feedback

Warming boosts outgoing infrared radiation, promoting cooling.

IPCC Role

Assesses climate science, impacts, risks, and mitigation strategies.

IPCC Conclusion

Humans have unequivocally caused global warming via GHG emissions.

GHG Trends

GHGs (greenhouse gases) are rising rapidly due to human activity.

Isotopic CO2 Evidence

Declining C13 in CO2 confirms fossil fuel origin of emissions.

Observed Warming

About 1.1°C; not explainable by natural causes alone.

Climate Models

Simulate Earth's climate using physical equations; match observations only when human input is included.

Natural vs Human Forcing

Only human + natural factors explain recent warming patterns.

Pollution Masking

Some air pollutants have a cooling effect that partially offsets GHG warming.

Most Potent GHG

Carbon dioxide contributes most to long-term warming.

Climate Impact by Region

All inhabited regions are already affected (IPCC AR6).

Emissions Scenarios (SSPs)

High: SSP3-7.0 / SSP5-8.5; Low: SSP1-1.9 / SSP1-2.6; Intermediate: SSP2-4.5.

Main Warming Driver

Future CO2 emissions.

Air Pollution Definition

Airborne solids/liquids/gases harmful to health or environment.

Natural Pollutant Sources

Volcanoes, windborne dust, wildfires.

Human Pollutant Sources

Fixed (factories, power plants) and mobile (vehicles, planes).

Primary vs Secondary Pollutants

Primary: emitted directly; Secondary: formed via atmospheric reactions.

Carbon Monoxide (CO)

Colorless, odorless, toxic gas from incomplete combustion, mostly vehicles.

Particulate Matter (PM)

Suspended solids/droplets harmful to lungs and visibility.

PM-10 vs PM-2.5

PM-2.5 is finer, stays airborne longer, and penetrates deeper.

Sulfur Dioxide (SO2)

From burning sulfur fuels; can form acid rain via H2SO4.

Volatile Organic Compounds (VOCs)

Hydrocarbons like methane and benzene; ozone precursors.

Nitrogen Oxides (NOx)

Formed in high-temp combustion; contribute to acid rain and ozone.

Ozone (O3)

Secondary pollutant in troposphere; irritates lungs, harms vegetation.

Pollution Trends Since 1970

Most U.S. emissions have declined due to Clean Air Act.

Air Quality Index (AQI)

EPA's scale (0-500); values >100 are unhealthful.

Wind & Pollution

Strong winds disperse pollution; weak winds concentrate it.

Atmospheric Stability

Stable air resists vertical motion, trapping pollution (e.g., inversion).

Topography & Pollution

Valleys trap cold air and pollution; e.g., LA basin effect.