Climate change adaptation is the process of adjusting to current or expected climate change and its effects. It is one of the ways to respond to climate change, along with mitigation. For humans, adaptation aims to moderate or avoid harm, and exploit opportunities; for natural systems, humans may intervene to help adjustment.
Adaptation actions can be either incremental (actions where the central aim is to maintain the essence and integrity of a system) or transformative (actions that change the fundamental attributes of a system in response to climate change and its impacts).
The need for adaptation varies from place to place, depending on the sensitivity and vulnerability to environmental impacts. Adaptation is especially important in developing countries since those countries are most vulnerable to climate change and are bearing the brunt of the effects of global warming. Human adaptive capacity is unevenly distributed across different regions and populations, and developing countries generally have less capacity to adapt. Adaptive capacity is closely linked to social and economic development. In general higher levels of development mean higher adaptive capacity, but some development locks people in to certain patterns or behaviors. And the most developed areas may have low adaptation capacity to new hazards, not previously experienced, relative to more familiar hazards.
The economic costs of adaptation to climate change are likely to cost billions of dollars annually for the next several decades, though the exact amount of money needed is unknown. In addition to the direct costs associated with adaptation, there is also an indirect cost arising from a diversion of resources from productive towards adaptive capital (known as the adaptive investment effect). The adaptation challenge grows with the magnitude and the rate of climate change. Even the most effective climate change mitigation through reduction of greenhouse gas (GHG) emissions or enhanced removal of these gases from the atmosphere (through carbon sinks) would not prevent further climate change impacts, making the need for adaptation unavoidable and the adaptation gap is growing. The Paris Agreement requires countries to keep global temperature rise this century to less than 2 °C above pre-industrial levels, and to pursue efforts to limit the temperature increase to 1.5 °C. Even if emissions are stopped relatively soon, global warming and its effects will last many years due to the inertia of the climate system, so both net zero and adaptation are necessary.
Sustainable Development Goal 13, set in 2015, targets to strengthen countries' resilience and adaptive capacities to climate-related issues. This adjustment includes many areas such as infrastructure, agriculture and education. The Paris Agreement, adopted in the same year, included several provisions for adaptation. It seeks to promote the idea of global responsibility, improve communication via the adaption component of the Nationally Determined Contributions, and includes an agreement that developed countries should provide some financial support and technology transfer to promote adaptation in more vulnerable countries. Some scientists are concerned that climate adaptation programs might interfere with the existing development programs and thus lead to unintended consequences such as maladaptation for vulnerable groups. The economic and social costs of unmitigated climate change would be very high.
Adaptation can help decrease climate risk via the three risk factors: hazards, vulnerability and exposure. Impacts of climate hazards may be reduced with the help of ecosystem-based adaptation. For instance, flooding may be prevented if mangroves have the ability to dampen storm energy. As such, protection of the mangrove ecosystem can be a form of adaptation. Insurance and livelihood diversification increase resilience and decrease vulnerability. Further actions to decrease vulnerability include strengthening social protection and building infrastructure more resistant to hazards. Exposure can be decreased by retreating from areas with high climate risks, such as floodplains and by improving systems for early warnings and evacuations.
Main article: Effects of climate change
The projected effects for the environment and for civilization are numerous and varied. The main effect is an increasing global average temperature. As of 2013[update] the average surface temperature could increase by a further 0.3 to 4.8 °C (0.5 to 8.6 °F) by the end of the century. This is causing a variety of secondary effects where in many cases the extent of change is uncertain. The most important of these are changes in patterns of precipitation, rising sea levels, altered patterns of agriculture, increased extreme weather events, the expansion of the range of tropical diseases, and the opening of new marine trade routes. Climate change will also have multifaceted social effects including inequity (social inequality), poverty and increased burden on women as main food and care providers for households. However, social effects such as increased migration, and conflict over resources like water and land, are generally hard to attribute to climate change as the only or main driver of change.
Potential biophysical effects include sea level rise of 110 to 770 mm (0.36 to 2.5 feet) between 1990 and 2100, repercussions to agriculture, possible slowing of the thermohaline circulation, reductions in the ozone layer, increased intensity and frequency of extreme weather events, lowering of ocean pH, and the spread of tropical diseases such as malaria and dengue fever.
IPCC Working Group II, the United States National Academy of Sciences, the United Nations Disaster Risk Reduction Office, and other science policy experts agree that while mitigating the emission of greenhouse gases is important, adaptation to the effects of global warming will still be necessary. Mitigating global warming is an economic and political challenge. Given that greenhouse gas levels are already elevated,[by how much?] the lag of decades between emissions and some impacts, and the significant economic and political challenges of success, it is uncertain how much climate change will be mitigated.
There are some synergies and trade-offs between adaptation and mitigation. Adaptation measures often offer short-term benefits, whereas mitigation has longer-term benefits. Sometimes climate-relevant actions may point in different directions. For instance, compact urban development may lead to reduced transport and building greenhouse gas emissions. Simultaneously, it may increase the urban heat island effect, leading to higher temperatures and increasing exposure, making adaptation more challenging.
Synergies include the benefits of public transport for both mitigation and adaptation. Public transport has lower greenhouse gas emissions per kilometer travelled than cars. A good public transport network also increases resilience in case of disasters: evacuation and emergency access becomes easier. Reduced air pollution from public transport improves health, which in turn may lead to improved economic resilience, as healthy workers perform better.
After assessing the literature on sustainability and climate change, scientists concluded with high confidence that up to the year 2050, an effort to cap GHG emissions at 550 ppm would benefit developing countries significantly. This was judged to be especially the case when combined with enhanced adaptation. By 2100, however, it was still judged likely that there would be significant climate change impacts. This was judged to be the case even with aggressive mitigation and significantly enhanced adaptive capacity.
Adaption actions can be grouped into three categories:: 845
There are a wide variety of adaptation options for flooding:
Dealing with more frequent drenching rains may required increasing the capacity of stormwater systems, and separating stormwater from blackwater, so that overflows in peak periods do not contaminate rivers. One example is the SMART Tunnel in Kuala Lumpur.
New York City produced a comprehensive report for its Rebuilding and Resiliency initiative after Hurricane Sandy. Its efforts include not only making buildings less prone to flooding, but taking steps to reduce the future recurrence of specific problems encountered during and after the storm: weeks-long fuel shortages even in unaffected areas due to legal and transportation problems, flooded health care facilities, insurance premium increases, damage to electricity and steam generation in addition to distribution networks, and flooding of subway and roadway tunnels.
Further information: Sea level rise § Adaptation
Adaptation options to sea level rise can be broadly classified into retreat, accommodate and protect. Retreating involves moving people and infrastructure to less exposed areas and preventing further development in areas at risk. This type of adaptation is potentially disruptive, as displacement of people may lead to tensions. Accommodation options make societies more flexible to sea level rise. Examples are the cultivation of food crops that tolerate a high salt content in the soil and making new building standards which require building to be built higher and incur less damage in the case a flood does occur. Finally, areas can be protected by the construction of dams, dikes and by improving natural defenses. In the United States, the Environmental Protection Agency supports the development and maintenance of water supply infrastructure nationwide, especially in coastal cities, and more coastal cities and countries are actively implementing this approach. Besides, storm surges and flooding can be instantaneous and devastating to cities, and some coastal areas have begun investing in storm water valves to cope with more frequent and severe flooding during high tides.
Glacial lake outburst floods may become a bigger concern due to the retreat of glaciers, leaving behind numerous lakes that are impounded by often weak terminal moraine dams. In the past, the sudden failure of these dams has resulted in localized property damage, injury and deaths. Glacial lakes in danger of bursting can have their moraines replaced with concrete dams (which may also provide hydroelectric power).
Climate change can threaten food security and water security. Food systems can be adapted to enhance food security and to prevent future negative impacts from climate change.
See also: Climate change and agriculture
A significant effect of global climate change is the altering of global rainfall patterns, with certain effects on agriculture. Rainfed agriculture constitutes 80% of global agriculture. Many of the 852 million poor people in the world live in parts of Asia and Africa that depend on rainfall to cultivate food crops. Climate change will modify rainfall, evaporation, runoff, and soil moisture storage. Extended drought can cause the failure of small and marginal farms with resultant economic, political and social disruption, more so than this currently occurs.
Agriculture of any kind is strongly influenced by the availability of water. Changes in total seasonal precipitation or in its pattern of variability are both important. The occurrence of moisture stress during flowering, pollination, and grain-filling is harmful to most crops and particularly so to corn, soybeans, and wheat. Increased evaporation from the soil and accelerated transpiration in the plants themselves will cause moisture stress.
Adaptive ideas include:
A 2020 study projects that regions inhabited by a third of the human population could become as hot as the hottest parts of the Sahara within 50 years without a change in patterns of population growth and without migration, unless greenhouse gas emissions are substantially reduced to a limit of 1.5 °C of warming. The most affected regions have little adaptive capacity as of 2020.
Projects to adapt to or to reduce heat include:
Ecosystems adapt to global warming depending on their resilience to climatic changes. Humans can help adaptation in ecosystems for biodiversity. Possible responses include increasing connectivity between ecosystems, allowing species to migrate to more favorable climate conditions and species relocation. Protection and restoration of natural and semi-natural areas also helps build resilience, making it easier for ecosystems to adapt.
Many of the actions that promote adaptation in ecosystems, also help humans adapt via ecosystem-based adaptation and nature-based solutions. For instance, restoration of natural fire regimes makes catastrophic fires less likely, and reduces the human exposure to this hazard. Giving rivers more space allows for storage of more water in the natural system, making floods in inhabited areas less likely. The provision of green spaces and tree planting creates shade for livestock. There is a trade-off between agricultural production and the restoration of ecosystems in some areas.
Furthermore, humans can help ecosystems adapt to and become more resilient against climate change and its impacts. For instance, scientific research and development could be used to help coral reefs survive climate change.
Reforestation is one of the ways to stop desertification fueled by anthropogenic climate change and non sustainable land use. One of the most important projects is the Great Green Wall that should stop the expansion of Sahara desert to the south. By 2018 only 15% of it is accomplished, but there are already many positive effects, which include: "Over 12 million acres (5 million hectares) of degraded land has been restored in Nigeria; roughly 30 million acres of drought-resistant trees have been planted across Senegal; and a whopping 37 million acres of land has been restored in Ethiopia – just to name a few of the states involved." "Many groundwater wells [were] refilled with drinking water, rural towns with additional food supplies, and new sources of work and income for villagers, thanks to the need for tree maintenance."
The demand for water for irrigation is projected to rise in a warmer climate, bringing increased competition between agriculture—already the largest consumer of water resources in semi-arid regions—and urban as well as industrial users. Falling water tables and the resulting increase in the energy needed to pump water will make the practice of irrigation more expensive, particularly when with drier conditions more water will be required per acre. Other strategies will be needed to make the most efficient use of water resources. For example, the International Water Management Institute has suggested five strategies that could help Asia feed its growing population in light of climate change. These are: Modernising existing irrigation schemes to suit modern methods of farming; supporting farmers' efforts to find their own water supplies, by tapping into groundwater in a sustainable way; Looking beyond conventional "Participatory Irrigation Management" schemes, by engaging the private sector; Expanding capacity and knowledge; Investing outside the irrigation sector.
Further information: Disaster response § Disaster response technologies
As climate change is projected to increase frequency and severity of extreme weather events and disasters, adaptation may also include measures towards increased preparedness and relevant disaster response capacities.
Main article: weather modification
Russian and American scientists have in the past[relevant?] tried to control the weather, for example by seeding clouds with chemicals to try to produce rain when and where it is needed. China has implemented a cloud seeding machine that is controlled through remote sensing technologies. The World Meteorological Organization (WMO) through its Commission for Atmospheric Sciences (CAS) opined in 2007: "Purposeful augmentation of precipitation, reduction of hail damage, dispersion of fog and other types of cloud and storm modifications by cloud seeding are developing technologies which are still striving to achieve a sound scientific foundation and which have to be adapted to enormously varied natural conditions."
A rather new activity in the domain of climatology applied to adaptation is the development and implementation of climate services that "provide climate information to help individuals and organizations to make climate smart decisions". Most recognized applications of climate services are in domains like agriculture, energy, disaster risk reduction, health and water. In Europe a large framework called C3S for supplying climate services has been implemented by the European Union Copernicus programme.
Adaptive capacity is the ability of a system (human, natural or managed) to adjust to climate change (including climate variability and extremes) to moderate potential damages, to take advantage of opportunities, or to cope with consequences. As a property, adaptive capacity is distinct from adaptation itself. Those societies that can respond to change quickly and successfully have a high adaptive capacity. High adaptive capacity does not necessarily translate into successful adaptation. For example, adaptive capacity in Western Europe is generally considered to be high, and the risks of warmer winters increasing the range of livestock diseases is well documented, but many parts of Europe were still badly affected by outbreaks of the Bluetongue virus in livestock in 2007. Adaptive capacity may include the capacity to produce, widely deploy and develop efficient and sustainable cooling technologies to protect populations against elevated temperatures.
Unmitigated climate change (i.e., future climate change without efforts to limit greenhouse gas emissions) would, in the long term, be likely to exceed the capacity of natural, managed and human systems to adapt.
It has been found that efforts to enhance adaptive capacity can help to reduce vulnerability to climate change. In many instances, activities to promote sustainable development can also act to enhance people's adaptive capacity to climate change. These activities can include: Improving access to resources, reducing poverty, lowering inequities of resources and wealth among groups, improving education and information, improving infrastructure, improving institutional capacity and efficiency, promoting local indigenous practices, knowledge, and experiences.
Others have suggested that certain forms of gender inequity should be addressed at the same time; for example women may have participation in decision-making, or be constrained by lower levels of education.
Researchers at the Overseas Development Institute found that development interventions to increase adaptive capacity have tended not to result in increased agency for local people. They argue that this should play a more prominent part in future intervention planning because agency is a central factor in all other aspects of adaptive capacity. Asset holdings and the ability to convert these resources through institutional and market processes are central to agency.
Migration can be seen as adaptation: people may be able to generate more income, diversify livelihoods, and spread climate risk. This contrasts with two other frames around migration and environmental change: migration as a human rights issue and migration as a security issue. In the human right's frame, normative implications include developing protection frameworks for migrants, whereas increased border security may be an implication of framing migration as a national security issue. Sometimes these approaches are combined for the development of solutions (laws and policies) that aim to be both viable, taking national concerns into account, and in accordance with human rights. Furthermore, there may also be economic aspects of migration – high levels of migration and emigration of skilled workers – that decision-makers in both the – distant or nearby – host country and the country of origin may consider. Vice versa, climate change could also exacerbate economic insecurity or political instability as causes for migration beyond temperatures and extreme weather events.
Would-be migrants often need access to social and financial capital, such as support networks in the chosen destination and the funds or physical resources to be able to move. Migration is frequently the last adaptive response households will take when confronted with environmental factors that threaten their livelihoods, and mostly resorted to when other mechanisms to cope have proven unsuccessful.
Migration events are multi-causal, with the environment being just a factor amongst many. Many discussions around migration are based on projections, while relatively few use current migration data. Migration related to sudden events like hurricanes, heavy rains, floods, and landslides is often short-distance, involuntary, and temporary. Slow-impact events, such as droughts and slowly rising temperatures, have more mixed effects. People may lose the means to migrate, leading to a net decrease in migration. The migration that does take place is seen as voluntary and economically motivated.
Focusing on climate change as the issue may frame the debate around migration in terms of projections, causing the research to be speculative. Migration as tool for climate change adaptation is projected to be a more pressing issue in the decade to come. In Africa, specifically, migrant social networks can help to build social capital to increase the social resilience in the communities of origin and trigger innovations across regions by the transfer of knowledge, technology, remittances and other resources.
In Africa, Mozambique and Zimbabwe are clear examples of adaptation strategies because they have implemented relocation policies that have reduced the exposure of populations and migrants to disaster. Tools can be put in place that limit forced displacement after a disaster; promote employment programs, even if only temporary, for internally displaced people or establish funding plans to ensure their security; to minimize the vulnerability of populations from risk areas. This can limit the displacement caused by environmental shocks and better channel the positive spillovers (money transfers, experiences, etc.) from the migration to the origin countries/communities.
Relocation from the effects of climate change has been brought to light more and more over the years from the constant increasing effects of climate change in the world. Coastal homes in the U.S. are in danger from climate change, this is leading residents to relocate to areas that are less affected. Flooding in coastal areas and drought have been the main reasons for relocation.
Assisted colonization is the act of moving plants or animals to a different habitat. The destination habitat may or may not have once previously held the species; the only requirement is the destination habitat must provide the bioclimatic requirements to support the species. The goal of assisted colonization is to remove the species from a threatening environment and give them a chance to survive and reproduce in an environment that does not pose an existential threat to the species.
In recent years, assisted colonization has been presented as a potential solution to the climate change crisis that has changed environments faster than natural selection can adapt to. While assisted colonization has the potential to allow species that have poor natural dispersal abilities to avoid extinction, it has also sparked intense debate over the possibility of the introduction of invasive species and diseases into previously healthy ecosystems. Despite these debates, scientists and land managers have already begun the process of assisted colonization for certain species.
In the North American context, assisted colonization is most often discussed in the context of the relocalization of the continent's forests. In the late 2000s and early 2010s, the Canadian provinces of Alberta and British Columbia modified their tree reseeding guidelines to account for the northward movement of forest's optimal ranges. British Columbia even gave the green light for the relocation of a single species, the Western Larch, 1000 km northward.
See also: climate risk insurance
Insurance spreads the financial impact of flooding and other extreme weather events. Although it can be preferable to take a proactive approach to eliminate the cause of the risk, reactive post-harm compensation can be used as a last resort. Access to reinsurance may be a form of increasing the resiliency of cities. Where there are failures in the private insurance market, the public sector can subsidize premiums. A study identified key equity issues for policy considerations:
Government-subsidized insurance, such as the U.S. National Flood Insurance Program, is criticized for providing a perverse incentive to develop properties in hazardous areas, thereby increasing overall risk. It is also suggested that insurance can undermine other efforts to increase adaptation, for instance through property level protection and resilience. This behavioral effect may be countered with appropriate land-use policies that limit new construction where current or future climate risks are perceived and/or encourage the adoption of resilient building codes to mitigate potential damages.
Policies have been identified as important tools for integrating issues of climate change adaptation. At national levels, adaptation strategies may be found in National Action Plans (NAPS ) and National Adaptation Programme of Action (NAPA, in developing countries), and/or in national policies and strategies on climate change. These are at different levels of development in different countries.
Cities, states, and provinces often have considerable responsibility in land use planning, public health, and disaster management. Some have begun to take steps to adapt to threats intensified by climate change, such as flooding, bushfires, heatwaves, and rising sea levels.
Adaptive policy can occur at the global, national, or local scale, with outcomes dependent on the political will in that area. Scheraga and Grambsch identify nine principles to be considered when designing adaptation policy, including the effects of climate change varying by region, demographics, and effectiveness. Scheraga and Grambsch make it clear that climate change policy is impeded by the high level of variance surrounding climate change impacts as well as the diverse nature of the problems they face. James Titus, project manager for sea level rise at the U.S. Environmental Protection Agency, identifies the following criteria that policy makers should use in assessing responses to global warming: economic efficiency, flexibility, urgency, low cost, equity, institutional feasibility, unique or critical resources, health and safety, consistency, and private versus public sector.
Adaptation can mitigate the adverse impacts of climate change, but it will incur costs and will not prevent all damage. The IPCC points out that many adverse effects of climate change are not changes in the average conditions, but changes in the variation or the extremes of conditions. For example, the average sea level in a port might not be as important as the height of water during a storm surge (which causes flooding); the average rainfall in an area might not be as important as how frequent and severe droughts and extreme precipitation events become. Additionally, effective adaptive policy can be difficult to implement because policymakers are rewarded more for enacting short-term change, rather than long-term planning. Since the impacts of climate change are generally not seen in the short term, policymakers have less incentive to act. Furthermore, climate change is occurring on a global scale, leading to global policy and research efforts such as the Paris Agreement and research through the IPCC, creating a global framework for adapting to and combating climate change. The vast majority of climate change adaptation and mitigation policies are being implemented on a more local scale because different regions must adapt differently and because national and global policies are often more challenging to enact.
Adaptation can either occur in anticipation of change (anticipatory adaptation), or be a response to those changes (reactive adaptation). Most adaptation being implemented at present[when?] is responding to current climate trends and variability, for example increased use of artificial snow-making in the European Alps. Some adaptation measures, however, are anticipating future climate change, such as the construction of the Confederation Bridge in Canada at a higher elevation to take into account the effect of future sea-level rise on ship clearance under the bridge.
Much adaptation takes place in relation to short-term climate variability, however this may cause maladaptation to longer-term climatic trends. For example, the expansion of irrigation in Egypt into the Western Sinai desert after a period of higher river flows is a maladaptation when viewed in relation to the longer term projections of drying in the region. Adaptations at one scale can also create externalities at another by reducing the adaptive capacity of other actors. This is often the case when broad assessments of the costs and benefits of adaptation are examined at smaller scales and it is possible to see that whilst the adaptation may benefit some actors, it has a negative effect on others.
People have always adapted to climatic changes and some community coping strategies already exist, for example changing sowing times or adopting new water-saving techniques. Traditional knowledge and coping strategies must be maintained and strengthened, otherwise adaptive capacity may be weakened as local knowledge of the environment is lost. Strengthening these local techniques and building upon them also makes it more likely that adaptation strategies will be adopted, as it creates more community ownership and involvement in the process. In many cases this will not be enough to adapt to new conditions which are outside the range of those previously experienced, and new techniques will be needed. The incremental adaptations which have been implemented become insufficient as the vulnerabilities and risks of climate change increase, this causes a need for transformational adaptations which are much larger and costlier. Current development efforts are increasingly focusing on community-based climate change adaptation, seeking to enhance local knowledge, participation and ownership of adaptation strategies.
The United Nations Framework Convention on Climate Change, under Article 11, incorporates a financial mechanism to developing country parties to support them with adaptation. Until 2009, three funds existed under the UNFCCC financial mechanism. The Special Climate Change Fund (SCCF) and the Least Developed Countries Fund (LDCF) are administered by the Global Environmental Facility. The Adaptation Fund was established a result of negotiations during COP15 and COP16 and is administered by its own Secretariat. Initially, when the Kyoto Protocol was in operation, the Adaptation Fund was financed by a 2% levy on the Clean Development Mechanism (CDM).
At the 2009 Copenhagen Summit, nations committed to the goal of sending $100 billion per year to developing countries for climate change mitigation and adaptation by 2020. The Green Climate Fund was created in 2010 as one of the channels for mobilizing this climate finance. At the 2015 Paris conference, it was clarified that the $100 billion per year should involve a balanced split between mitigation and adaptation. As of December 2020[update], the promised $100 billion per year had not been fully delivered, and most developing country finance was still targeted towards mitigation, with adaptation only receiving a 21% share of the public finance provided in 2020.
An extensive research literature assesses options for responses to global warming. Much of this literature addresses the potential economic costs associated with different strategies. The Asian Development Bank has a series of studies on the Economics of Climate Change in the Asia-Pacific region. These studies provide cost analysis of both adaptation and mitigation measures. The WEAP (Water Evaluation And Planning system) assists water resources researchers and planners in assessing impacts of and adaptations to climate change. The United Nations Development Programme's Climate Change Adaptation Portal includes studies on climate change adaptation in Africa, Europe and Central Asia, and Asia and the Pacific.
In addition to the direct costs associated with spending on adaptation and mitigation there is also research indicating the cost associated with diverting resources away from productive sources towards these adaptation purposes. Such a diversion is termed the adaptive investment effect (AIE) and evidence suggests that the impact of investment on economic growth is reduced by around 30% in areas which invest heavily in adaptive technologies. 
A key and defining feature of international adaptation finance is its premise on the concept of additionality. This reflects the linkages between adaptation finance and other levels of development aid. Many developed countries already provide international aid assistance to developing countries to address challenges such as poverty, malnutrition, food insecurity, availability of drinking water, indebtedness, illiteracy, unemployment, local resource conflicts, and lower technological development. Climate change threatens to exacerbate or stall progress on fixing some of these pre-existing problems, and creates new problems. To avoid existing aid being redirected, additionality refers to the extra costs of adaptation.
The four main definitions of additionality are:
A criticism of additionality is that it encourages business as usual that does not account for the future risks of climate change. Some advocates have thus proposed integrating climate change adaptation into poverty reduction programs.
From 2010 to 2020, Denmark increased its global warming adaptation aid 33%, from 0.09% of GDP to 0.12% of GDP, but not by additionality. Instead, the aid was subtracted from other foreign assistance funds. Politiken wrote: "Climate assistance is taken from the poorest."
One way economic systems may adapt and increase adaptation to climate change is by expanding industries and activities that develop and implement structural and physical adaptation options.
The economic impacts of climate change are the economic implications brought about by the effects of climate change. The effects of climate change include: ocean water becoming warmer and more acidic, rising sea levels, extreme weather events (such as, flooding and drought) becoming more common, and extended weather season. The economic impacts of climate change also include any mitigation (for example, limiting the global average temperature below 2 °C) or adaption (for example, building flood defences) employed by nations or groups of nations, which might infer economic consequences.The economic impacts of climate change are seen in recent studies. In 2017, climate change contributed to extreme weather events causing at least $100 billion in damages. The impact can be seen over a longer time period, where "over the past 20 years, an estimated 500,000 people have died and US$3.5 trillion was lost as a result of extreme weather events". Increasing temperature will lead to accelerating economic losses.: 16 A 2017 survey of independent economists looking at the effects of climate change found that future damage estimates range "from 2% to 10% or more of global GDP per year."
A 2020 United Nations report found that while 72% of countries had a high level adaption instrument – such as a plan, policy or strategy – relatively few had progressed to the tangible implementation of projects. At least not to the point where the climate risk their populations are exposed to had been significantly reduced.
See also: Climate change and cities
A May 2021 report based on a survey of 812 global cities found that while 93% reported they are at risk from climate change, 43% did not have an adaption plan, and 41% of cities had not carried out a climate risk and vulnerability assessment.