6.3 Climate change — mitigation and adaptationIB Environmental Systems and Societies SL: Revision notes

Greenhouse gases mix throughout the atmosphere, so emissions in one country affect everyone. To avoid the risk of catastrophic climate change, global action is required, not measures adopted only by certain states. If some states cut emissions while others increase theirs, the reductions are cancelled out, and industries may move to places with weaker rules (carbon leakage).

Responses fall into two groups: mitigation (tackling the causes) and adaptation (coping with the effects).

Decarbonisation is reducing or ending the use of energy sources that emit CO2 and replacing them with renewable energy (wind, solar, hydro, geothermal).

A variety of mitigation strategies address climate change:

• Replacing fossil fuels with renewables, for example Denmark replacing coal with wind power.
• Improving energy efficiency (insulation, efficient appliances) and reducing demand.
• Sustainable transport: electric vehicles, public transport, cycling.
• Carbon sequestration: protecting forests and reforestation, restoring wetlands and soils.
• Carbon capture and storage and reducing methane (landfill gas capture, changes in agriculture).

Adaptation strategies aim to reduce adverse effects and to maximise any positive consequences (for example longer growing seasons in some regions). Examples:

• Flood defences, raised homes and cyclone shelters (Bangladesh).
• Drought-resistant or salt-tolerant crops and changed planting times.
• Better water management, including storage and efficient irrigation.
• Early-warning systems, planned migration and urban green space to reduce heat.

Adaptation protects people directly and can be done at local or national level, but does not stop the warming itself.

Individuals and societies on a range of scales are developing adaptation plans. A National Adaptation Programme of Action (NAPA) is prepared by least developed countries to identify their urgent adaptation needs. Bangladesh was among the first to produce one (2005).

Cities, businesses and communities also write resilience and adaptation plans, aiming to build the capacity of systems to withstand and recover from climate impacts. Effective strategies combine mitigation and adaptation, because adaptation alone cannot cope with unlimited warming.