Climate Change as a Hazard
Long-term shift in global temperatures and weather patterns - the defining challenge of our time
+1.2°C
Above pre-industrial
420+ ppm
CO₂ concentration
3mm/yr
Sea level rise
>95%
Scientific certainty
What is Climate Change?
Climate change is a long-term shift (decades to millennia) in global average temperatures and weather patterns. While climate has always changed naturally, the current warming is happening at an unprecedented rate - faster than any time in the last 10,000 years. Global temperature is now 1.2°C above pre-industrial levels (1850 baseline) and rising approximately 0.18°C per decade.
Evidence for Climate Change
Multiple independent lines of evidence all point to the same conclusion:
Temperature Records
- • Rising 0.18°C per decade (last 100 years)
- • Last 5 years = warmest on record
- • Ocean temperatures also rising
Ice & Glaciers
- • Mountain glaciers retreating worldwide
- • Arctic sea ice declining (summer minimum shrinking)
- • Greenland/Antarctic ice sheets losing mass
Sea Level
- • Rising 3 mm/year (accelerating)
- • Thermal expansion (water expands when heated)
- • Glacial melt adding water to oceans
Ecological Changes
- • Species migrating to cooler climates
- • Breeding seasons shifting earlier
- • Coral bleaching events increasing
Atmospheric CO₂
Currently 420+ ppm - the highest in 3 million years. Increasing at 2 ppm/year. Pre-industrial level was 280 ppm (stable for thousands of years).
Interactive: CO₂ & Climate Simulator
393
CO₂ (ppm)
+1.0°C
Temperature
+16cm
Sea Level
Great acceleration: Post-war economic boom. CO₂ emissions accelerating rapidly. Global temperature starting measurable rise.
Causes of Climate Change
Natural Causes (Pre-industrial)
Solar variation: 11-year sunspot cycle affects energy output
Orbital cycles: Milankovitch cycles change Earth's position relative to sun (100,000+ year timescales)
Volcanic eruptions: SO₂ in stratosphere causes temporary cooling
Ocean circulation: El Niño/La Niña redistribute heat
Human Causes (Since 1850)
Fossil fuels: CO₂ from coal, oil, gas (~65% of emissions)
Agriculture: Methane from livestock + rice paddies
Fertilizers: N₂O from agricultural runoff
Deforestation: Removes CO₂-absorbing trees, releases stored carbon
Industry: Cement production is major CO₂ source
Why THIS Time is Different
- • Rate of change is unprecedented in last 10,000 years
- • Humans are the dominant cause (>95% scientific certainty, IPCC 2021)
- • CO₂ concentration changing faster than natural cycles
Interactive: Emissions by Sector
Click a sector to see mitigation options
The Greenhouse Effect
Essential for life - without it Earth would be -18°C
- 1. Solar radiation enters atmosphere
- 2. Some absorbed by surface, warming it
- 3. Surface radiates heat (infrared)
- 4. GHGs (CO₂, CH₄, N₂O) absorb this heat
- 5. Heat radiates back to surface
- 6. Result: Surface stays warm enough for life
The current problem - too much of a good thing
Human activities have increased GHG concentrations:
This is the cause of current climate change
Global Impacts of Climate Change
Temperature & Weather
Heatwaves more frequent, intense, and longer. Heat-related illness/death increasing. Wet areas getting wetter (flooding risk ↑), dry areas getting drier (drought risk ↑). Weather patterns becoming more unpredictable.
Sea Level & Coasts
Rising 3 mm/year from thermal expansion + glacial melt. Threatening low-lying coastal areas and island nations. Saltwater intrusion into freshwater aquifers. Coastal erosion accelerating.
Ecosystems & Biodiversity
Species extinction (can't adapt/migrate fast enough). Habitat loss as climate zones shift. Food chains disrupted. Disease vectors expanding (e.g., malaria spreading poleward).
Food & Water Security
Crop yields declining from heat, drought, flooding. Livestock productivity reduced. Fishing stocks shifting location. 2 billion people depend on glacial water (Himalayas, Alps, Andes) - threatened by glacial melt.
Economic & Social
Rising insurance costs. Infrastructure damage from extreme weather. Agricultural losses. Climate migration (climate refugees). Potential conflict over scarce resources (water, arable land).
Climate Change as a Hazard Multiplier
Direct Hazards
- • More intense tropical storms (more ocean energy)
- • Longer, more severe droughts
- • Extreme heat events
- • Flooding from extreme rainfall
Indirect Hazards
- • Famine from crop failure
- • Disease outbreaks spreading
- • Water scarcity conflicts
- • Mass migration (climate refugees)
- • Economic collapse in vulnerable regions
Interactive: Vulnerability Explorer
Select Region Type
Select Climate Hazard
Key vulnerability factors:
- •Low-lying delta regions
- •Limited funds for sea defenses
- •High population density on coast
- •Agriculture dependent on coastal land
Who is Most Vulnerable?
- LICs: Limited resources for adaptation, agriculture-dependent, food security precarious
- Small island states: Rising sea levels are existential threat
- Arid regions: Droughts intensifying existing water stress
- Megacities in developing world: Overcrowded, informal settlements, poor drainage
Mitigation vs Adaptation
Reduce GHG emissions - slow the warming
- • Shift to renewable energy
- • Improve energy efficiency
- • Protect and restore forests
- • Reduce meat consumption
- • Carbon capture technology
Cope with impacts - live with the changes
- • Build flood defenses
- • Develop drought-resistant crops
- • Heat-resistant buildings
- • Improve healthcare systems
- • Planned relocation from vulnerable areas
Key point: Both are needed. Mitigation alone won't stop all change because some warming is already "locked in" from past emissions. Adaptation alone won't work if warming continues unchecked.
Interactive: Adaptation Strategy Selector
Select a climate threat:
Choose a response strategy:
Test Your Knowledge
Current atmospheric CO₂ is approximately:
Exam Practice
Climate change is projected to increase tropical storm intensity by 10-20% over the next 50 years due to warmer ocean temperatures. Discuss how this will affect countries at different development levels differently.
Key Terms
Grade 8/9 Focus
- • Link climate change to increased natural hazard frequency and intensity
- • Explain unequal vulnerability - why same hazard affects LICs/HICs differently
- • Distinguish clearly between mitigation and adaptation with specific examples
- • Use precise statistics: 420+ ppm CO₂, +1.2°C warming, 3mm/year sea level rise, >95% scientific certainty