Climate Change: Effects & Responses
Climate change is already having significant impacts on people and the environment around the world. The AQA GCSE specification requires you to understand the effects of climate change and evaluate the different strategies used to manage it. This lesson covers the social, economic, and environmental effects, and the key approaches: mitigation (reducing causes) and adaptation (adjusting to effects).
Effects of Climate Change
Climate change affects the world in many interconnected ways. Effects can be grouped into social, economic, and environmental categories.
Environmental Effects
| Effect | Detail |
|---|
| Rising sea levels | Thermal expansion and melting ice are causing seas to rise; threatens low-lying coastal areas and island nations |
| Melting ice caps and glaciers | Arctic sea ice declining ~13% per decade; Greenland and Antarctic ice sheets losing mass |
| More extreme weather | Increased frequency and intensity of heatwaves, droughts, floods, and storms |
| Ocean acidification | Oceans absorb CO2, forming carbonic acid; pH has dropped by ~0.1 since pre-industrial times, threatening marine life |
| Coral bleaching | Warmer oceans cause coral to expel the algae they depend on; mass bleaching events are becoming more frequent (e.g. Great Barrier Reef) |
| Shifts in ecosystems | Species migrate to higher latitudes/altitudes; some cannot adapt fast enough and face extinction |
| Permafrost thawing | Melting permafrost in Arctic regions releases stored methane (a powerful greenhouse gas), creating a dangerous feedback loop |
| Changes in precipitation | Some regions becoming wetter, others drier; changing patterns of seasonal rainfall |
Social Effects (impacts on people)
- Health risks — increased heatstroke, dehydration, and respiratory illness during heatwaves. Tropical diseases (e.g. malaria, dengue) may spread to new areas as temperatures rise.
- Water scarcity — changing rainfall patterns and glacial retreat threaten water supplies for billions of people, particularly in Africa, the Middle East, and South Asia.
- Food insecurity — crop yields may decline in tropical regions due to heat stress and drought. Some temperate regions may see temporary increases in agricultural productivity.
- Climate refugees — rising sea levels and extreme weather may force millions to migrate. Low-lying island nations such as Tuvalu, Kiribati, and the Maldives face existential threats.
- Conflict — competition for shrinking resources (water, farmland) may increase tensions and contribute to conflict, particularly in vulnerable regions.
- Inequality — the poorest and most vulnerable communities, who have contributed least to climate change, are often the most severely affected.
Economic Effects (impacts on money and business)
- Damage costs — extreme weather events are becoming more expensive. Global weather-related disaster costs have increased significantly over recent decades.
- Agricultural losses — droughts, floods, and heatwaves damage crops and reduce yields. This can drive up food prices globally.
- Infrastructure damage — coastal erosion, flooding, and extreme heat damage roads, railways, buildings, and power networks.
- Tourism — some destinations may become too hot or lose their natural attractions (e.g. coral reefs, ski resorts with declining snow cover).
- New opportunities — some regions may benefit: longer growing seasons in northern latitudes, new Arctic shipping routes as ice melts, increased demand for renewable energy technology.
Exam Tip: Effects of climate change are not all negative. The examiner may ask you to evaluate both positive and negative effects. Be balanced — mention potential benefits (e.g. longer growing seasons in some areas) alongside the much larger negative impacts.
Managing Climate Change: Mitigation vs Adaptation
There are two main approaches to managing climate change:
| Approach | Definition | Aim |
|---|
| Mitigation | Actions to reduce or prevent greenhouse gas emissions | Tackle the causes of climate change |
| Adaptation | Actions to adjust to the effects of climate change | Reduce the impacts of climate change |
Both are needed: mitigation to slow future warming, and adaptation to deal with changes already underway.
Mitigation Strategies
1. Renewable Energy
Replacing fossil fuels with clean energy sources:
| Source | How It Works | Advantages | Disadvantages |
|---|
| Solar | Photovoltaic panels convert sunlight to electricity | No emissions; falling costs; abundant | Intermittent; requires storage; land use |
| Wind | Turbines convert wind energy to electricity | No emissions; cheap onshore; offshore potential | Visual impact; intermittent; noise |
| Hydroelectric | Dams use flowing water to generate electricity | Reliable; no emissions during operation | Ecosystem disruption; high upfront cost |
| Nuclear | Fission reactions generate heat for electricity | Low carbon; reliable baseload power | Radioactive waste; high cost; safety concerns |
| Geothermal | Heat from the Earth's interior | Reliable; low emissions | Location-dependent; high drilling costs |
2. Carbon Capture and Storage (CCS)
- Technology that captures CO2 emissions from power stations and industrial plants before they enter the atmosphere.
- The captured CO2 is then transported and stored underground in geological formations (e.g. depleted oil and gas fields).
- Still in early stages of large-scale deployment; expensive but potentially important for industries that are hard to decarbonise.
3. International Agreements
- Paris Agreement (2015) — 196 countries agreed to limit global warming to well below 2 °C above pre-industrial levels, with efforts to limit to 1.5 °C.
- Countries submit Nationally Determined Contributions (NDCs) — their plans for reducing emissions.
- Challenges: some countries have been slow to act; targets are not legally binding; developing nations argue that wealthier nations should bear more responsibility.
4. Afforestation and Reforestation
- Planting new forests (afforestation) and restoring degraded forests (reforestation) to absorb CO2 from the atmosphere.
- Trees act as carbon sinks — they absorb CO2 during photosynthesis and store it in their biomass.
- The UK government has committed to planting 30,000 hectares of new woodland per year.
5. Reducing Deforestation
- Tropical deforestation (e.g. in the Amazon, Congo Basin, and Southeast Asia) releases vast amounts of stored carbon.
- Programmes such as REDD+ (Reducing Emissions from Deforestation and forest Degradation) provide financial incentives for developing countries to protect their forests.
6. Transport and Lifestyle Changes
- Shifting to electric vehicles — reducing emissions from transport.
- Improving public transport — reducing car dependency.
- Dietary changes — reducing meat consumption (especially beef) to lower agricultural methane emissions.
- Energy efficiency — insulating homes, using LED lighting, smart heating systems.
Exam Tip: Mitigation strategies tackle the causes of climate change. If a question asks about reducing climate change, focus on how emissions are being cut. Do not confuse this with adaptation (adjusting to effects).
Adaptation Strategies
1. Flood Defences
- Building and upgrading sea walls, flood barriers, and embankments to protect against rising sea levels and increased rainfall.
- Example: The Thames Barrier in London protects the city from tidal surges; it has been used with increasing frequency.
- Managed retreat — allowing some low-value coastal areas to flood naturally rather than building expensive defences.
2. Water Management
- Desalination plants — converting seawater to freshwater (used in countries like Saudi Arabia, Australia, and Israel).
- Water recycling — treating and reusing wastewater.
- Rainwater harvesting — collecting rainfall for household and agricultural use.
- Drought-resistant crops — developing and planting crop varieties that can tolerate drier conditions.
3. Agricultural Adaptation
- Changing crop types — growing crops better suited to new climate conditions (e.g. vineyards expanding in southern England).
- Irrigation improvements — drip irrigation and precision agriculture reduce water waste.
- Diversification — farmers growing a wider variety of crops to reduce the risk of total crop failure.
4. Urban Planning
- Green roofs and walls — plants on buildings absorb rainwater and reduce the urban heat island effect.
- Sustainable drainage systems (SuDS) — permeable surfaces, swales, and retention ponds manage surface water.
- Urban tree planting — shade reduces temperatures and trees absorb CO2.
- Building design — better insulation, natural ventilation, and lighter-coloured surfaces to reduce cooling demands.
5. Emergency Planning