Climate change is associated with substantial risks for human society and nature. Adaptation and migration are not new concepts, and civilisation has adapted to climatic events over centuries, including managed retreat for example and migrating away from risks and hazards. However, recent climate change is unprecedented and rapidly occurring, while knowledge and tactics has improved overtime also. There are two fundamental response options, mitigation of climate change and adaptation.

Mitigation means limiting climate change by reducing emissions of greenhouse gases or enhancing / expanding greenhouse gas sinks. Adaptation means protecting vulnerable systems or moderating harm caused by climate change, or exploiting opportunities (McCarthy et al. 2001).

Mitigation has traditionally garnered more support than adaptation due to its ability to reduce impact on all nations and systems, while adaptation is limiting, reserved for a few who can afford it. For example, the atoll nations would scarcely be able to adapt if their nations are submerged by seawater. Moreover, the benefits of mitigation are predictable and measurable, resolving the root problem climate change other than its symptoms. Adaptation however is difficult to predict and measure as it depends on the accuracy of climate and impact projections. Those who require adaptation are likely to be developing nations who, largely, have not contributed to the climate change crisis.

Both adaptation and mitigation require international recognition AND participation. The efforts of the international community, such as shown in the Kyoto Protocol, and the undermining of these efforts over the period can seriously impact the power of mitigation and it’s benefits. Adaptation policies are having greater credence due climate change already affecting average climate conditions and climate extremes (Hegerl and Zwiers 2007).

	Mitigation of climate change	Adaptation to climate change
Target systems	All systems	Selected Systems
Scale of effect	Global	Local to Regional
Lifetime	Centuries	Years to centuries
Lead time	Decades	Immediate to decades
Effectiveness	Certain	Generally Less Certain
Ancillary benefits	Sometimes	Often
Polluter pays	Typically	Not Always
Actor benefits	Only Little	Almost Fully
Monitoring	Relatively Easy	More Difficult

Adaptation

The diversity of adaptation is illustrated by the following key dimensions (partly based on Smit et al. 1999):

• Climate-sensitive domains: Adaptation is relevant for all climate-sensitive domains, including agriculture, forestry, water management, coastal protection, public health, and disaster prevention.
  
• Types of climate hazard: Adaptation can be motivated by a diverse set of current and future climate hazards, including observed and expected changes in average climate, climate variability, and climate extremes.
  
• Predictability of climatic changes: Some aspects of future climate change can be predicted with reasonably high confidence (e.g. changes in average temperature) whereas others are associated with large uncertainty (e.g. changes in hurricane tracks and intensity).
  
• Non-climatic conditions: Adaptation occurs against a background of environmental, economic, political, and cultural conditions that vary substantially across regions.
  
• Purposefulness: Adaptation can be either autonomous (e.g. reducing physical activity during a heatwave) or purposefully planned (e.g. adopting new building codes).
  
• Timing: Planned adaptation can be either reactive (i.e. after some impacts have been experienced) or proactive/ anticipatory (i.e. before major damage has occurred).
  
• Planning horizon: The time horizon of planned adaptation can vary substantially, from a few months to many decades.
  
• Form: Adaptation involves a broad range of measures, including technical, institutional, legal, educational, and behavioural measures. Research and data collection may also be considered as adaptation measures (in a wider sense), because they facilitate implementation of effective actions for reducing climatic risks.
  
• Actors: Adaptation involves a wide range of people at different hierarchy levels in many public and private organizations

Adaptation is by no means the simpler solution, and there is no one approach for assessing, planning, and implementing adaptation measures. Adaptation assessments must therefore be flexible, but also work with new and improved knowledge.

Adaptation can include better established methods such as disaster risk management (e.g. early-warning
systems), coastal management (e.g. structural protection), resource management (e.g. water rights allocation), spatial planning (e.g. flood zone protection), urban planning (e.g. building codes), public health (e.g. disease surveillance), and agricultural outreach (e.g. seasonal forecasts).

Examples include:-

• More sustainable infrastructure, that could anticipate and withstand weather events
• Replanting forests and restoring damaged ecosystems
• Diversifying agriculture and embracing biodiversity to build resilience
• Investigate, develop and innovate solutions to manage natural risks and hazards
• Develop action plans for climate emergencies and build and international stage to address specific issues

International and national organizations have developed guidelines for climate impact and adaptation assessment. Widely applied generic guidelines include the

• IPCC Technical Guidelines (IPCC, 1994)
• International Handbook (USCSP 1994)
• UNEP Handbook (UNEP, 1998)
• UNDP-GEF Adaptation Policy Framework (UNDP, 2005)
• Climate Change Adaptation through Integrated Risk Assessment (CCAIRR, 2005)

Mitigation

In 2015, the Paris agreement was introduced with the main objective of limiting global temperature increase to 2 °C by 2100 and pursuing efforts to limit the increase to 1.5 °C. A range of conventional and less conventional methods were discussed in mitigating climate change.

Decarbonisation

Decarbonisation technologies and techniques reduce CO₂ emissions, such as renewable energy, fuel switching, efficiency gains, nuclear power, and carbon capture storage and utilization. Most of these technologies are well established and carry an acceptable level of managed risk (Ricke et al. 2017; Victor et al. 2018; Bataille et al. 2018; Mathy et al. 2018; Shinnar and Citro 2008; Bustreo et al. 2019).

Carbon Capture

There are some new technologies that capture and sequester CO₂ from the atmosphere, also called negative emissions technologies or carbon dioxide removal methods (Ricke et al. 2017). These methods are mainly biological, such as biochar, enhanced weathering, direct air carbon capture and storage, ocean fertilization, ocean alkalinity enhancement, soil carbon sequestration, afforestation and reforestation, wetland construction and restoration, as well as alternative negative emissions utilization and storage methods such as mineral carbonation and using biomass in construction (Lawrence et al. 2018; Palmer 2019; McLaren 2012; Yan et al. 2019; McGlashan et al. 2012; Goglio et al. 2020; Lin 2019; Pires 2019; RoyalSociety 2018; Lenzi 2018).

Altering Radiation

Altering the earth’s radiation balance through the management of solar and terrestrial radiation could stabilise the climate or reduce climatic effects. This is also called radiative forcing geoengineering technologies. Unlike negative emissions technologies, this is achieved without altering greenhouse gas concentrations in the atmosphere. Some methods include stratospheric aerosol injection, marine sky brightening, cirrus cloud thinning, space-based mirrors, surface-based brightening and various radiation management techniques. All these techniques are still theoretical or in conception, and there remains uncertainty and risk.

Examples include:-

• Improve energy efficient and opt for renewable energies to reduce emissions
• Tax the use of fossil fuels and actively reduce emissions either through reduced usage or increasing carbon sinks.
• Promote sustainable transport schemes such as electric modes of transport, and reduce air travel
• Promote sustainable agricultural methods and farming to preserve land uses, food security and reduce emissions.

Have a think about any other ideas – what more do you think can be done to either reduce emissions or the impact of climate change on both human society and on nature?