ENV199 Week 2 - Climate Change Background

Guy and Sarah

Changing Temperature and Rain Patterns

Evidence of climate change through shifts in global temperature and precipitation trends.

Ocean Temperature, Sea Level, and Acidity

Rising ocean heat, levels, and acidification due to climate change.

Melting of Glaciers and Sea Ice

Major indicator of global warming, leading to sea level rise and ecosystem disruption.

Extreme Weather Events

Increased frequency and severity of heatwaves, storms, and floods.

Shifts in Ecosystem Characteristics

Changes in species distribution, migration, and biodiversity due to altered climates.

Greenhouse Effect

Process where gases trap heat in Earth’s atmosphere, warming the planet.

Main Human Sources of Greenhouse Gases

Fossil fuel burning, deforestation, and industrial processes since 1950.

Carbon Dioxide

Primary greenhouse gas emitted by burning fossil fuels, waste, and biomass.

Carbon Cycle

Continuous movement of carbon between the atmosphere, land, and oceans.

Aerosols

Microscopic airborne particles from fossil fuels or biomass that can cool or warm the Earth.

Climate Feedbacks

Natural processes that amplify or reduce climate changes (e.g., ice melt, clouds).

Water Vapor Feedback

Positive feedback: more heat increases evaporation, adding more greenhouse effect.

Melting Arctic Sea Ice

Positive feedback: darker surfaces absorb more sunlight, warming further.

Cloud Feedback

Mixed feedback: clouds can both reflect sunlight (cooling) and trap heat (warming).

Human Activity

Dominant cause of recent global warming.

Earth’s Orbit and Rotation

Natural factors influencing climate patterns and ice ages.

Solar Activity

Variations in the Sun’s output affecting Earth’s climate.

Earth’s Reflectivity (Albedo)

Surfaces like snow reflect sunlight; darker ones absorb it.

Volcanic Activity

Releases aerosols that reflect sunlight, temporarily cooling the atmosphere.

Heatwaves

Periods of extreme heat intensified by climate change.

U.S. Warming Trends

U.S. temperatures have risen 60% more than the global average since 1970.

Heatwave Impacts

Affect health, agriculture, labor productivity, and increase energy costs.

Vulnerable Populations

Children, elderly, pregnant women, and marginalized communities.

Ocean Acidification

Oceans absorb ~25% of atmospheric CO₂, becoming more acidic.

Aragonite Saturation

Lower levels hinder shell and skeleton formation in marine organisms.

Warming of the Planet

Global surface temperature has increased by 1.1°C since pre-industrial times.

Greenhouse Gas Concentrations

CO₂, methane, and nitrous oxide at highest levels in millions of years.

Sea Level Rise

Global average sea level has risen 0.2 meters since 1901.

Vulnerable Populations to Climate Change

3.3–3.6 billion people live in highly affected regions.

Reduced Food and Water Security

Climate impacts agriculture, livestock, and water availability.

Future Climate Risks

More frequent heatwaves, floods, and droughts predicted.

Sea Level and Ocean Changes

Increased flooding and threats to fisheries due to rising temperatures.

Ecosystem Loss

Glacial melt, permafrost thaw, and species extinctions nearing irreversibility.

Societal Impacts

Food insecurity, displacement, and developmental challenges.

Compound Extreme Events

Multiple climate stresses that amplify human and ecological risks.

Mental Health Effects

Rising temperatures and disasters linked to trauma and anxiety.

Adaptation

Adjusting to climate change to reduce harm or exploit benefits.

Mitigation

Efforts to limit climate change by reducing emissions.

Net Zero Emissions

Balancing emissions with carbon removal by 2050 to limit warming to 1.5°C.

Policy and Financial Gaps

Discrepancy between global climate goals and implemented actions.

Paris Agreement

International effort to reduce emissions; progress remains limited.

Maladaptation

Poorly planned actions that worsen vulnerability to climate risks.

Inclusive Climate Planning

Requires fair, community-based decision-making to avoid harm.

Carbon Budgets

Limits on cumulative emissions to stay within temperature targets.

Carbon Dioxide Removal

Technologies or natural processes that extract CO₂ from the atmosphere.

Climate Change

Long-term changes to the Earth's natural systems largely caused by human activities and the greenhouse effect.

Greenhouse Gases

Gases like CO₂, CH₄, N₂O, and H₂O that trap heat within the atmosphere and contribute to climate change.

Greenhouse Effect

The process by which greenhouse gases trap the sun’s heat, warming the Earth’s atmosphere.

Feedback Loops

Processes that reinforce climate change effects, such as sea ice melting and permafrost thawing.

Albedo Effect

When ice melts and exposes darker surfaces, increasing heat absorption and accelerating warming.

Permafrost Melt

Thawing of frozen ground that releases methane and CO₂, amplifying global warming.

Major Impacts of Climate Change

Rising sea levels, extreme weather, flooding, health risks, and wildlife loss.

Why CO₂ Matters Most

Although less potent than methane, CO₂ is more abundant and measured in parts per million (ppm).

CO₂ Emission Sources

Transport, heating, energy production, and melting ice release carbon dioxide.

Least Developed Countries (LDCs)

Nations most disproportionately affected by climate change despite contributing the least.

UNFCCC

United Nations Framework Convention on Climate Change — global framework guiding nations on climate action.

Keeling Curve

Graph showing the steady increase of atmospheric CO₂ over time.

Jet Stream

Fast air current separating cold and warm regions, influenced by temperature differences.

IPCC AR6

Sixth Assessment Report of the Intergovernmental Panel on Climate Change summarizing global climate impacts.

Disproportionate Impacts

Vulnerable communities like those in Africa, Asia, and small islands face the worst effects despite low emissions.

Indigenous and Low-Income Populations

Groups most affected by climate change due to economic and geographic vulnerabilities.

Climate Finance Gap

Wealthy nations have failed to meet the $100 billion/year funding goal to help developing countries adapt.

Adaptation Challenges

Current adaptation measures are fragmented, incremental, and unequally distributed.

Urban Heat Extremes

Cities experience intensified heat extremes due to urbanization and climate change.

Projected Global Risks

Every region will face greater climate hazards in the near future, posing risks to ecosystems and humans.

LDC Climate Group

Coalition of least developed countries advocating for stronger global climate action (see Lilongwe Declaration).