Warming / Climate Change & Ozone Loss

Is climate change new?

No. Climate has changed many times over Earth’s 4.7-billion-year history due to natural processes.

Natural cause of past climate change: volcanic eruptions

Volcanoes release ash and gases that block sunlight and cool the Earth short-term.

Natural cause of past climate change: solar cycles

Changes in solar output affect how much energy Earth receives.

Natural cause of past climate change: continental drift

Moving continents change ocean currents and atmospheric circulation.

Natural cause of past climate change: meteor impacts

Impacts release dust that blocks sunlight and alters climate.

What are ice cores used for?

Ice cores trap ancient air bubbles that reveal past atmospheric gas composition.

What do ice core gases tell scientists?

Past CO₂, methane, and temperature levels.

What is dendrochronology?

The study of tree rings to determine past climate conditions.

What do tree ring widths indicate?

Growing conditions such as temperature and rainfall.

How far back do direct temperature records go?

To about the 1860s.

When did satellite temperature data begin?

Around the 1960s.

When did direct CO₂ measurements begin?

1958 (Mauna Loa data).

What is the IPCC?

Intergovernmental Panel on Climate Change.

Who created the IPCC and when?

The UN’s World Meteorological Organization in 1988.

What does the IPCC do?

Reviews climate data, forms scientific consensus, makes predictions and recommendations.

What is the greenhouse effect?

Gases absorb and re-radiate heat, trapping warmth in the troposphere.

Is the greenhouse effect bad?

No—it is natural and necessary for life.

What is enhanced greenhouse effect?

Increased greenhouse gases from human activities causing extra warming.

What does “anthropogenic” mean?

Caused by humans.

Other names for enhanced greenhouse warming

Global warming, climate change, AGW, ACC.

Greenhouse gas: Carbon dioxide (CO₂)

Source: burning fossil fuels, deforestation, land clearing.

Warming power of CO₂

Baseline = 1.

Greenhouse gas: Methane (CH₄)

Sources: natural gas leaks, cow burps, rice paddies, landfills.

Warming power of methane

25× stronger than CO₂.

Greenhouse gas: Nitrous oxide (N₂O)

Source: bacterial breakdown of fertilizers, whipped cream propellants.

Warming power of nitrous oxide

300× stronger than CO₂.

Greenhouse gas: CFCs

Sources: refrigerants, aerosols, packing materials.

Warming power of CFCs

1000× stronger than CO₂.

Average global temperature increase

1.1°C (1.9°F).

Cryosphere evidence of warming

Melting sea ice, ice caps, glaciers, and permafrost.

What causes sea level rise?

Thermal expansion of water + melting ice.

What are environmental refugees?

People displaced due to climate-related environmental changes.

Role of oceans in climate

Absorb and release heat.

Another ocean role

Distribute heat via currents.

Third ocean role

Absorb and release CO₂.

Why are clouds a climate “mystery”?

Different cloud types warm or cool the Earth.

Altostratus clouds effect

Cool the Earth.

Cirrus clouds effect

Warm the Earth.

Role of global wind circulation cells

Distribute heat and moisture worldwide.

What happens if wind circulation is disrupted?

Major global climate impacts.

Soil impacts of climate change

Changes in temperature and rainfall increase erosion and reduce productivity.

Methane release from melting ice

Increases warming via positive feedback loop.

Methane release from swamps/marshes

Reduces biodiversity and increases warming.

Ice-albedo feedback

Less ice  lower albedo  more heat absorbed  more warming  even less ice.

Disease movement due to warming

Tropical diseases move into temperate regions.

Marine species impact

Habitat loss from sea level rise and photic zone changes.

What is coral bleaching?

Coral lose symbiotic algae, turn white, and may die.

Big policy question about climate change

Do economic costs outweigh environmental benefits?

Prevention strategy for climate change

Stop producing greenhouse gases.

Why is cleanup difficult?

Greenhouse gases persist (like toothpaste back in the tube).

What is carbon sequestration?

Capturing and storing carbon to reduce atmospheric CO₂.

Simple sequestration method

Planting trees.

What is CCS?

Carbon Capture and Storage.

How does CCS work?

Capture CO₂ and inject it deep underground.

Kyoto Protocol (1997)

International agreement to reduce greenhouse gas emissions.

Paris Accord (2016)

Global agreement to limit climate change by reducing emissions.

Transportation changes to reduce CO₂

Walk, bike, drive fuel-efficient vehicles.

Thermostat changes

Adjust to reduce energy use.

Home efficiency actions

Insulate and seal house.

Lighting choice

Use energy-efficient lighting.

Diet change

Reduce meat consumption.

Laundry habit

Wash clothes in cold or warm water.

Carbon offset action

Plant trees.

Where is the ozone layer located?

Stratosphere.

What is ozone chemically?

O₃.

Role of the ozone layer

Filters harmful UV radiation.

Why is ozone essential for life?

Prevents DNA damage and skin cancer.

Why were CFCs popular?

Cheap, nonflammable, noncorrosive, non-toxic, effective.

Why are CFCs bad?

Destroy ozone and are powerful greenhouse gases.

Key atom responsible for ozone destruction

Chlorine (Cl).

Why is chlorine dangerous to ozone?

It is regenerated and destroys many ozone molecules.

When does the polar vortex form?

Antarctic winter (June–August).

What happens inside the polar vortex?

Ice crystals collect CFCs.

What triggers ozone destruction in spring?

Sunlight returns in October.

What happens when the vortex breaks up?

Ozone-depleted air spreads over the Southern Hemisphere.

Human health effect

Increased skin cancer.

Effect on phytoplankton

Killed by UV, reducing oxygen production.

Effect on crops

Lower crop yields.

Air pollution effect

Increased photochemical smog.

How can ozone depletion be prevented?

Eliminate ODCs and use substitutes (e.g., HCFCs).

Montreal Protocol (1987)

International treaty reducing ozone-depleting chemicals.

Copenhagen Protocol (1992)

Strengthened restrictions on CFCs and ODCs.