Global assessment climate security

A country’s national security may be negatively affected by climate change. Not just with respect to safety and conflict, but in a broader sense encompassing human welfare that could be threatened, for example by extreme weather phenomena, ocean acidification, or sea level rise. Scientists have developed a method to express this impact of climate change quantitatively (75). In their approach, climate security comprises seven dimensions: water security, food security, energy security, sea level rise impact on inhabited land, social stability, health, and economic resilience. For 187 countries, each dimension was evaluated by means of three related components:

• Exposure: the number of people and the amounts of resources and assets affected by climate change
• Sensitivity: the degree to which a sector is affected, either positively or negatively
• Adaptive capacity: the ability of the human system to adjust to, take advantage of, or respond to consequences of climate change 

Each of these three components is a function of one or more specialized indicators, which comprise time series from 1901 up to 2016, depending on the availability of data. 

As a result, they presented a ranking of these 187 countries according to their climate security standing. Finland is number 1. European countries, New Zealand, Canada, and Australia occupy the top ten places of their list. European countries also share places 11 to 20 with the USA. The most climate-vulnerable countries in the world are the Sub-Saharan Mauritania, Somalia, and South Sudan, and some Small Island Developing States, such as Maldives, Marshall Islands, and Tuvalu (75). 

In addition to this ranking, the study provides useful information about the strengths and weaknesses of a country to deal with the impacts of climate change, and thus helps to identify those policies that have the highest potential of improving climate security. It turns out that in the developed world the indicators with the highest potential to improve climate security are renewable energy consumption, population aging, and the impact of sea level rise. In less-developed countries, Gross Domestic Product per capita, corruption, and population growth are the most important indicators (75).

Indeed, in developing countries, more people die due to climate-related disasters because developing countries are more vulnerable to hazards such as floods, droughts and heat waves. The same hazard may cause a major disaster in one country while passing unnoticed in another. In developing countries, human health and food security are more exposed to variability in the climate system. This was confirmed by results from an analysis of natural disasters from 1950 to 2015, registered in the world’s best known and most used database of climate-related disasters, the Emergency Events Database (EM-DAT). Whether extreme weather, a climate anomaly, leads to a disaster largely depends on the vulnerability of a country. The more developed a country is, the less vulnerable it is to climate variability. This means that the same climate anomaly is more likely to cause a disaster in a developing compared with a developed country. Developed countries require larger climate anomalies to experience a disaster (98). 

No clear evidence relating climate change to armed conflict and refugee flows

People living in places affected by violent conflict are particularly vulnerable to climate change. Evidence shows that large-scale violent conflict harms infrastructure, institutions, natural capital, social capital and livelihood opportunities. Since these assets facilitate adaptation to climate change, there are strong grounds to infer that conflict strongly influences vulnerability to climate change impacts (67). Vice versa, research does not conclude that there is a strong positive relationship between warming and armed conflict (68,69,79,83,97,99,105).

Environmental scarcity caused by climate change has been implicated as a driver of violent conflict but there is significant bias in the regions analysed for climate-conflict links, and the potential for climate change to cause armed conflict may be exaggerated because of this. The large body of peer-reviewed research on climate–conflict links is skewed in three major ways: 1. Scholars have gone looking for climate-conflict links in countries and regions that have been conflict-affected, rather than
 those most affected by climate change; 2. Scholars have not focused
 more attention on those cases most likely to be affected by climate change; 3. Scholars focused on cases where it is more convenient to conduct research (78,100). 


Concerns about the implications of climate change for security through its impact on hydrological resources have been expressed at the highest political level, but research has still not established a causal link between hydro-climatic variability (or water scarcity) and international or civil violence (56). Although under certain social conditions they might aggravate the risk of conflict, water scarcity and climate change are overall not found to have an important association with armed conflict, especially if compared to poverty and dysfunctional institutions (57). In fact, the opposite effect has been discussed: periods of acute scarcity may incline individuals to focus on immediate survival rather than engage in costly, destructive, organized armed violence, while periods of relative abundance free up resources and labor can create more advantageous tactical environments for conflict (65).

The war in Syria may serve as an example. According to a number of experts, it was the Syrian regime’s failure to establish proper water governance and irrigation systems in the south of the country that led to unpreparedness when drought hit harder than usual. While drought led to major internal migration, the reasons were not the drought itself (70,74). The impact of droughts depends on the geopolitical setting and adaptive capacity of societies, as Syria’s civil war outbreak illustrates (74). Several social factors and causal mechanisms play a role in turning climate-induced stress into violent conflicts. The interactions between physical, geopolitical and intra-state factors need to be considered (74). 

The same line of reasoning holds for mass migration. Climate change-induced refugee flows are increasingly seen as one of the foremost crises of our times, blamed too easily on drought and climate change. The underlying reasons are far more complicated, however: poor governance, and poor water and land management also play a prominant role (69). 

Things may change in the future, though. Water may become a cause of war in the future due to climate change (62) and wars may not be fought over water, but caused by consequences of its scarcity, e.g. rising food prices or scarce arable land (58).

In 2009, the United Nations Secretary-General (UNSG) identified five ways in which climate change may be linked to international security (54):

1. by increasing human vulnerability to things like water and food insecurity;
2. obstructing and undermining economic development;
3. increasing the risk of violent conflict;
4. displacing large numbers of people or posing an existential threat to some states, such as those that could literally disappear under sea level rise;
5. contributing to international tensions by overwhelming bilateral and multilateral forms of cooperation in areas such as shared water basins.

Four possible pathways through which climate change could affect migration are (66):

1. Intensification of natural disasters
2. Increased warming and drought that affects agricultural production and access to clean water
3. Sea-level rise, which makes coastal areas and some island states increasingly uninhabitable
4. Competition over natural resources, leading to conflict and displacement of inhabitants.

However, some studies relate current climate variability to armed conflict

On the other hand, it has been demonstrated that civil conflict risk is associated with annual variations in the El Niño-Southern Oscillation (ENSO) during 1950–2004 (63): annual conflict risk, defined as the probability that a randomly selected country begins a civil conflict in a given year, doubles throughout the tropics when the global climate shifts from the cooler and wetter La Niña phase to the hotter and drier El Niño phase. According to the same study, 21% of conflicts since 1950 are attributable to movements in the global climate away from its most peaceful La Niña state. This study is considered the first to demonstrate that global climate changes, rather than just local or regional changes, have a measurable impact on conflict and stability around the world (64). In this respect it is important to stress that climate change is exacerbating pre-existing phenomena such as natural climatic variability (69). Warming trends since 1980 elevated conflict risk in Africa by 11% (73).

Besides, evidence from numerous contexts repeatedly finds that interpersonal violence increases with temperatures and sometimes low rainfall (72).  

Link between climate change and security is not that simple

The link between climate change and security threat is not as simple as often presented in the media (55,74,79,100):

• violence creates vulnerabilities that then make parts of the population more susceptible to direct damages from hydro-climatic change. Rather than climate change and water scarcity, it is political and economic factors that generate vulnerabilities that threaten the security of populations (59,74,99).
• dismantling of good institutions increases the likelihood of problems.
• in certain instances conflict may change institutions and/or reduce vulnerabilities in ways that enhance human security. Some researchers have argued that the Arab revolts were linked to drought and to the rise of grain prices (60). The Arab revolts may have had socially positive effects. Econometric studies confirm a link between droughts and democratic transitions for sub-Saharan countries (61).
• certain adaptation interventions (land-grabs or large dams) may generate conflict (mostly non-violent, and maladaptations may increase the vulnerability and undermine the security of certain parts of the population.
• what is good at one scale (e.g. national) may be bad at a different scale (e.g. human). A large dam that increases energy and national security may undermine the human security of local communities at its vicinity.

Again, the same can be concluded for mass migration and refugee flows.In the words of a recent report of the Stockholm International Water Institute SIWI (69): "Social, economic, and political factors affect the vulnerability or resilience of communities. In regions, the ability to cope with climate change and water scarcity decreases, and the likelihood of migration increases, as a result of factors that include poverty, low levels of education, lack of skills, weak institutions, limited infrastructure, lack
of technology and information, limited access to health care, poor access to resources, and the over-exploitation of resources, etc. Pull factors, such as a hope of a better life and employment, often combine to result in migration." 

It is also important to recognize that conflicts resulting from climate change will not necessarily be violent and can instead lead to changes in the distribution of power and resources, and protection of the things that are valued. Furthermore, research on international river basins shows that issues of water access and water scarcity in many cases lead to cooperation, rather than conflict (34). In short, the evidence about the links between environmental change and violent conflict is currently inconclusive.

Peacebuilding operations

Future security risks have been related to climate change by several countries and international organizations (52). Among scientists the link between climate change and conflict and national security is still a controversial topic, however (53). On the other hand, disaster and conflict often go hand in hand; in 60 years of peacebuilding operations in 49 countries, in only one case (Kosovo) were there no natural disasters (51).

Vulnerabilities - Transnational climate impacts

The countries that are most vulnerable to the direct impacts of climate change within their borders are concentrated in Africa and Asia (76,100). These direct impacts are only part of the story of a country’s vulnerability to climate change impacts, however. There are also so-called ‘transnational climate impacts’: climate impacts that reach across borders, affecting one country as a result of climate change or climate-induced extreme events in another country. When these transnational impacts are included as well in assessments of countries’ vulnerability to climate change, the world map of vulnerable countries has quite a different look (76).

The exposure to transnational climate impacts has been quantified and presented as a global index called the ‘Transnational Climate Impacts Index’. This index is made up of contributing indicators that cover four transnational risk pathways through which climate risk may propagate: biophysical systems, movement of people, financial flows and international trade (76).

The biophysical pathway encompasses changing flows of ecosystem services and resources from transboundary ecosystems such as river basins, oceans and the atmosphere. The finance pathway represents changing capital flows resulting from climate impacts on assets held overseas. The people pathway involves changing flows of people between countries as a result of climate impacts, e.g. migration and tourism. The trade pathway involves changing flows of goods and services via international supply chains and global markets. These four risk pathways operate over two different geographical scales; transboundary impacts are transmitted over borders between neighbouring countries, whereas teleconnected impacts result from more remote links, over greater distances (76).

European countries - direct risk low, transnational risk high: In a global perspective, the vulnerability of European countries to the direct impacts of climate change within their borders is low. However, the transnational climate impacts of some European countries is among the highest worldwide. These countries include mainly the Benelux countries, but also Germany, Switzerland and the Baltic States, as well as Montenegro, Malta and Portugal. In the top ranking of most vulnerable countries, The Netherlands stands out. Only eight countries are more vulnerable than The Netherlands, and all of them are in Sub-Saharan-Africa and the Middle East. The high position of The Netherlands seems to be related to its global openness as a trading nation that also makes the country highly exposed to transnational climate impacts (76).

Adaptation as a global collective endeavour: According to the authors of this study, their results should be used primarily to raise awareness and start discussions about the relevance of transnational climate impacts. Due to their global interconnected nature and the complexity described above, these impacts imply a need for enhanced international cooperation on adaptation. This places climate change adaptation in a new light, where adaptation is seen more as a global collective endeavour, rather than a purely local one, which tends to dominate current assessments of climate impacts (77). This also suggests that countries with a high score on transnational climate impacts’ might choose to engage in adaptation in countries upon which they depend heavily, or to undertake measures to stabilise volatile markets (76).

Cross-border vulnerabilities of the EU to drought

The EU’s economy is highly vulnerable to drought outside its borders due to climate change. The vulnerability of the EU’s agricultural imports to drought sharply increases within the next twenty to thirty years for some key imported crops such as sugar cane, cocoa, coffee, and palm oil. There is a moderate climate vulnerability for soybeans, imported to the EU on a large scale to meet the demand for animal feed. There is a high to very high vulnerability for coffee, cocoa, and palm oil imports. More than 44% of the EU’s agricultural imports will become highly vulnerable to drought in the future because of climate change (101).

Climate change and migration

Climate change can potentially influence the drivers of migration through different climatic hazards such as a rise in sea level, change in the frequency and intensity of tropical storms and cyclones, changes in rainfall patterns, increases in temperature and changes in atmospheric chemistry (80). These changes directly affect the environmental drivers of migration such as water availability and crop and pasture productivity, as well as provoking a loss of ecosystem services. Climate change also indirectly influences other drivers of migration. For instance, economic drivers are affected through the reduction of household incomes due to a decline in crop, livestock or fisheries productivity. Similarly, climate change exacerbates problems related to the availability of limited resources and violence emerges over access to these resources (81).

The relationship between climate change, conflict and migration is likely to follow the sequence of climate change exacerbating human conflict due to competition over scarce resources. For instance, recurrent severe droughts due to climate change can lead to conflict and instability in a country with poor management of natural resources. Consequently, climate- induced conflict outbreak drives displacement and outmigration (79).  

Recent studies suggest that climate change and associated adverse environmental impacts have the potential to trigger displacement of an increased number of people. Research further suggests that

• the bulk of migration will take place internally in individual countries;
• the majority of migration will come as a result of gradual changes in climate and not so much from individual catastrophic events;
• in most cases when hydro-climatic disasters occur in developing countries they will not lead to net out-migration because people tend to return to re-establish their lives after a disaster;
• long term environmental changes are likely to cause more permanent migration (31).

Recent studies (31) distinguish between migration driven by

• the increasing frequency and intensity of slow onset disasters such as drought and desertification;
• rapid onset disasters such as floods and cyclones, and
• incremental changes driven by sea-level rise.

Most studies agree that the most important climate change-related driver of migration will be sea-level rise, with the more careful assessments recognizing that the severity of migration will depend critically on the rate of localized changes in sea-level, and the degree to which adaptation takes place and is successful (32). These studies also recognize that the rate of migration driven by sea-level rise is likely to be slow, but steady, which suggests that disaster risk reduction and adaptation strategies may help avoid humanitarian crises and political instability.

Some studies also recognize that there may be some degree of exaggeration surrounding discussions of “environmental refugees” driven by climate change, creating the danger of inappropriate policy responses that do little to ensure the rights of those most at risk from climate change (33). While it does seem likely that climate change will be an additional contributor to migration, many studies emphasize that it is very unclear how many migrants there may be, where they may move from and to, and over what time scale. It is also widely recognized that environmental change is never a sole cause of migration, and that there are always one or more underlying economic, political or other social factors that make environmental change a proximate trigger, rather than an underlying driver of migration (33,82). Overall, the wide-ranging climatic effects on migration are not well understood (73,79).

Too poor to move

The wealth of a nation determines both the options and the willingness of its people to move to another part of the world. Citizens in wealthy nations can easily emigrate to another country but they will not do so because there is no reason to move. Citizens in poor countries have plenty of reasons to move but they lack the financial resources to do so. Emigration rates are highest in countries where people are rich enough to afford moving to another country and poor enough to feel the incentive to do so. Emigration rates tend to be highest in middle-income countries, and lower in both low-income and high-income countries (102).

Global warming may have reduced economic growth in most countries of the world over the last 30 years (123), and this reduction tends to be highest in the poorest countries. Climate change, therefore, may already have increased economic inequality between countries, on a global level (124). An analysis over the period 1990-2020 shows that, according to the authors, climate change is already a significant factor influencing migration patterns, be it less influential than other drivers of migration, such as economic inequalities, education, and demographic, social or cultural factors. They conclude that ‘recent climate change has acted to increase mobility in the richer parts of the world and decrease mobility in the poorest parts of the world’. In the richer parts of the world more people feel the incentive to migrate in response to climate change and can do so. In the poorest parts of the world, as a result of the adverse economic impacts of climate change, less people will have enough money to migrate (102).

The estimated impact of climate change on global migration patterns in the last 30 years is very small, though. Globally there were about 70 million migration movements per 5-year period, on average, according to the authors’ estimate. According to their analysis, climate change may have increased migration flows in the wealthier world regions by about 0.4%–0.5%. In the poorest world regions, on the other hand, migration flows may have decreased by roughly 0.5%–0.7% (102).

The Arab Spring

An analysis of refugee flows data for the years 2006-2015 for 157 countries showed no empirical evidence backing the existence of a robust link between climatic shocks, conflict and asylum seeking for the full period 2006–2015. Causal linkages were only found for the period 2010-2012, where global refugee flow dynamics were dominated by asylum seekers originating from Syria and countries affected by the Arab spring, as well as flows related to war episodes in Sub-Saharan Africa. For this 2010-2012 period, scientific evidence was found on the popular claim regarding the role of climate change on conflict and migration: climatic conditions, by affecting drought severity and the likelihood of armed conflict, seem to play a statistically significant role as an explanatory factor for asylum seeking exclusively for countries that were affected by the Arab Spring (79).

Excluding these regions from the analysis provides further statistical evidence, that the link between climate shocks, conflict and subsequent migration flows might rather be interpreted as a local phenomenon and therefore very specific to these regions. The authors of this study conclude that climate change will not generate asylum seeking everywhere but likely in a country undergoing political transformation where conflict represents a form of population discontent towards in- efficient response of the government to climate impacts (79).

Climate change and migration: Key role agriculture

The possible impact of climate change on migration is a complex issue. Among experts there is no clear consensus as to how gradual climate change, or natural disasters and extreme weather, influence migration (91). Migration is a complex phenomenon driven by a plurality of economic, social, demographic and historical factors, where climate change and natural disasters could, eventually, represent just one among many aspects (92).

The impact of global warming on agricultural productivity has been suggested as a potential key factor of the decision to migrate (93). This is because, on the one hand, agriculture is the main source of income and employment in the rural areas of developing countries, where the majority of migrants come from. On the other hand, agriculture is the sector mostly affected by climate change with important implications for agricultural productivity, rural livelihoods and food security, especially in the developing world (94).

The role of agriculture in the impact of climate change on migration was studied for a large data set of 108 countries covering data from 1960 to 2010. In their approach, the experts looked for a causalrelationship between changes in agricultural conditions driven by climatic shocks and migration outcomes. They also tested the role of other factors, such as overall income effects, conflicts, political instability and health issues, to make sure that it is really the agricultural channel through which climate change mainly impacts migration (90).

Agriculture is most vulnerable to weather changes. The more a country depends on agriculture, the stronger is the impact of weather anomalies on migration, some experts argue (95). Income in poor and middle-income countries, being largely dependent on the agricultural sector, therefore may be more affected by weather variability than incomes in more wealthy countries. Thus, the experts focused on these countries. A distinction was made in 60 poor and 48 middle-income countries. In poor countries people may not have the money to move and this may obscure climate change impacts. The poor countries are characterized by an agricultural share over GDP (30.8%) that is more than twice higher than the middle-poor sample (12.5%) (90). In principle the larger the importance of agriculture, the larger the potential impact of a climate shock in affecting the migration decision (96).

The results of this study show that negative climate-driven shocks to agriculture spur emigration from poor countries, but not from middle-poor ones. The impact on poor countries is at odds with the argument of many experts that poverty prevents the population in poor countries to emigrate. In poor countries, on average, climate-driven reduction in agricultural productivity of 1% from its decennial trend induces an increase in the emigration rate of about 4.5%, the study shows. Apparently, people are more likely to use migration as an adaptation response strategy in the poor and most vulnerable countries, where the agricultural sector represents the main income stream, technological adaptations are absent, and the population is more vulnerable to climate shocks (90).

The authors of this study conclude that their results support the idea that negative shocks to agricultural productivity caused by (long-run) weather variation, on average, positively affect net migration outflows (90).

Climate change and migration: the numbers

The current global stock of migrants consists of approximately 760 million internal migrants (based on figures from 2005) and 258 million international migrants. These estimates are conservative, and may not, for example, accurately account for return flows of migrants from destinations back to their places of origin. An estimated 67.5 million of these migrants are involuntarily displaced for reasons primarily related to conflict and natural hazards, because of political violence or persecution, or seek asylum in other countries for a variety of reasons (84).

Of these current migrant stocks and flows, it is difficult to estimate the number that move for reasons directly or indirectly attributable to climate events, due to uneven availability of statistical data on migration motivations, lack of a standard definition of what constitutes climate-related migration and the inherent multi-causality of migration (85). Climatic events and conditions typically interact with cultural, economic, political, social and other non-climatic processes to influence migration decision-making, and the climatic stimulus may be so tightly interwoven with other factors that it is difficult to disentangle and isolate (86).

Statistics from the International Displacement Monitoring Centre (IDMC) on the number of people directly displaced by climate-related hazards provide a rough indication of the relative influence of specific climate hazards on global migrant stocks (but underestimate the absolute numbers because involuntary displacement is only one form of climate-related migration). In 2018, approximately 16 million people, primarily in Asia, sub-Saharan Africa and the United States, were displaced by floods (5.4 million people), extreme storms (9.3 million people), droughts (764,000 people) and wildfires (424,000 people). Displacement numbers and locations vary from one year to the next, but the 2018 figures are generally reflective of average patterns of the past decade (84). Future decades will see more people living in locations that are increasingly exposed to the types of climatic hazards that regularly stimulate large population movements (84).

Vulnerabilities - According to the G7 members (2015)

In their 2015 report ‘A new climate for peace’ (71) the G7 members presented 7 ‘climate-fragility risks’:

1. Local resource competition. As the pressure on natural resources increases, competition can lead to instability and even violent conflict in the absence of effective dispute resolution.
2. Livelihood insecurity and migration. Climate changes will increase the human insecurity of people who depend on natural resources for their livelihoods, which could push them to migrate or turn to illegal sources of income.
3. Extreme weather events and disasters. Extreme weather events and disasters will exacerbate fragility challenges and can increase people’s vulnerability and grievances, especially in conflict-affected situations.
4. Volatile food prices and provision. Climate change is highly likely to disrupt food production in many regions, increasing prices and market volatility, and heightening the risk of protests, rioting, and civil conflict.
5. Transboundary water management. Transboundary waters are frequently a source of tension; as demand grows and climate impacts affect availability and quality, competition over water use will likely increase the pressure on existing governance structures.
6. Sea-level rise and coastal degradation. Rising sea levels will threaten the viability of low-lying areas even before they are submerged, leading to social disruption, displacement, and migration, while disagreements over maritime boundaries and ocean resources may increase.
7. Unintended effects of climate policies. As climate adaptation and mitigation policies are more broadly implemented, the risks of unintended negative effects — particularly in fragile contexts — will also increase. 

Vulnerabilities - According to the IPCC (2012)

In 2012 the IPCC published a special report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. Key findings in this report with respect to human security are summarized below (40).

Estimates of the numbers of current and future migrants due not only to disasters but generally to environmental change are divergent and controversial (41). A middle-range estimate puts the figure at 200 million by 2050 (42). Looking only at extreme weather as a cause of migration, a recent report estimates that over 20 million people were displaced due to sudden onset climate-related disasters in 2008 (43). This report and others, however, acknowledge the difficulty of disentangling the drivers of migration, including climate change risks, rising poverty, spread of infectious diseases, and conflict (44).

The relationship between climate risk and displacement is a complex one and there are numerous factors that affect migration (45). Nonetheless, recent research suggests that adverse environmental impacts associated with climate change have the potential to trigger displacement of an increased number of people (46). Studies suggest that most migration will take place internally within individual countries; that in most cases when climatic extremes occur in developing countries they will not lead to net outmigration because people tend to return to re-establish their lives after a disaster; and that while long-term environmental changes may cause more permanent migration this will also tend to be internal (47).

Attention has been mainly focused on population displacement associated with large disasters. However, the compound effect of smaller, more frequent events can also contribute to displacement. It is estimated that such extensive disasters account for an additional 19% displacement of people who are typically less visible than those displaced in larger events that attract international media and humanitarian assistance (48).

Concerns on the security implications of climate change range from increased needs for humanitarian assistance to concerns over environmental migration, emergent diseases for humans or in food chains, potentials for conflict between nations or localities over resources, and potential for political/governmental destabilization due to climate-related stresses in combination with other stresses, along with efforts to assign blame (49).

Climate change is generally regarded to act as a threat multiplier for instability in some of the most volatile regions of the world (50).

Vulnerabilities - According to the European Commission (2008)

Since the EU’s neighbours include some of the most vulnerable regions to climate change, e.g. North Africa and the Middle East, migratory pressure at the European Union's borders and political instability and conflicts could increase in the future. The European Commission published a paper that enumerates all the threats driven by climate change and related in one way or another to security issues (37):

• Conflicts over diminished resources: shortage of water, reduction of agricultural land, increased flooding and longer droughts may lead to economic losses and increased food prices. The overall effect is that climate change will fuel existing conflicts over depleting resources, especially where access to those resources is politicised.
• Economic damage and risk to coastal cities and critical infrastructure: Mega-cities, with their supporting infrastructure, such as port facilities and oil refineries, are often located by the sea or in river deltas. Sea-level rise and the increase in the frequency and intensity of natural disasters pose a serious threat to these regions and their economic prospects. The East coasts of China and India as well as the Caribbean region and Central America would be particularly affected. An increase in disasters and humanitarian crises will lead to immense pressure on the resources of donor countries, including capacities for emergency relief operations.
• Loss of territory and border disputes: Receding coastlines and submergence of large areas could result in loss of territory, including entire countries such as small island states. A further dimension of competition for energy resources lies in potential conflict over resources in Polar regions which will become exploitable as a consequence of global warming. Desertification could trigger a vicious circle of degradation, migration and conflicts over territory and borders that threatens the political stability of countries and regions.
• Environmentally-induced migration: Europe must expect more migration from its neighbouring and more vulnerable countries.
• Situations of fragility and radicalization: Climate change may significantly increase instability in weak or failing states by over-stretching the already limited capacity of governments to respond effectively to the challenges they face.
• Tension over energy supply: Intensified competition over access to, and control over, energy resources is, and will continue to be, a cause of instability. There is a possibility of greater energy insecurity and greater competition for resources. As previously inaccessible regions open up due to the effects of climate change, the scramble for resources will intensify.
• Pressure on international governance: Climate change impacts will fuel the politics of resentment between those most responsible for climate change and those most affected by it. Impacts of climate mitigation policies (or policy failures) will thus drive political tension nationally and internationally.

Vulnerabilities - According to the overview by O'Brien et al. (2008)

A very detailed overview on security implications of climate change has been presented by O’Brien et al. (2008) in the report: Disaster Risk Reduction, Climate Change Adaptation and Human Security (1). The implications presented in this report refer to the worldwide situation, not just one country in particular. Unless stated otherwise, the text presented below is a summary of this report.

Climate change, disaster risk reduction and security

Security concerns associated with climate change include the potential for conflict over natural resources, population displacement and migration as the result of sea-level rise or other large-scale biophysical, ecological or social disruptions, and the prospect of increasingly frequent humanitarian disasters as the result of extreme climate events.

Enhancing human security in the 21st century is about responding to climate change and disaster risks in ways that not only reduce vulnerability and conflict, but also create a more equitable, resilient and sustainable future.

The growing recognition that there may be an increasing number of disasters linked to floods, droughts, wildfires and other climate influenced events, coupled with increasing concern over the social implications of climate variability and change, calls for a much deeper and broader assessment of the connections between disaster risk reduction, climate change adaptation and human security.

Thus far, many of the discussions taking place on adaptation to climate change are not well-informed by disaster risk reduction strategies, tools, frameworks and experiences. At the same time, the disaster risk community has not fully incorporated climate change dimensions and information on climate impacts into its work. The risk of more complex, frequent, intense or unpredictable extreme weather events associated with global temperature increases, changing precipitation patterns and sea level rise, coupled with both gradual and non-linear changes to ecosystems and natural resources, suggests the need for a renewed focus on the ways that disaster risk reduction and adaptation can influence the context in which climate change occurs.

Climate change adaptation is defined as:“adjustments in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities” (2).

Disaster frequency

Records maintained by CRED (3) show that disaster frequency appears to be increasing, from about 100 events per decade in the 1900-1940, to 650 per decade in the 1960s, to 2000 per decade in the 1980s. By the 1990s this number had reached almost 2800 events per decade. The increase in reported disasters can be partly explained by a higher number of small and medium-level events that are related to natural and human-induced or socio-natural phenomena (4). While the number of geophysical disasters has remained fairly steady, the number of hydrometeorological disasters has increased significantly over the last decades (5).

It is estimated that global costs of weather-related disasters alone have increased from an annual average of USD 8.9 billion in 1977-1986 to USD 45.1 billion in the 1997-2006 period (6). According to ICSU about three-quarters of all disasters were triggered by weather-related events during the 1990s, and floods and drought are among the most prominent causes (7). A revised assessment of historical droughts (from 1900 to 2004) concludes that “more than half of all deaths associated with natural hazards are now classified as drought related, and only floods rank higher in terms of the number of people affected.” (8).

Mortality due to climate change is very likely to increase further through a range of direct effects (such as more intense heat waves, floods, and fires), indirect effects (such as declines in water quality and food security, and changes in disease vectors), and through social and economic disruptions (such as increased poverty and migration) (9). Climate change is likely to exacerbate the incidence of infectious diseases such as malaria, waterborne diseases such as diarrhea and cholera, and cardio-respiratory diseases. ERM estimated that even in the 1990s, some 35-40 percent of the worst disasters had a strong climate change signal, thus these statistics on losses are likely to increase in the absence of proactive climate change adaptation and disaster risk reduction (10).

Vulnerabilities - Urbanization

Recent research attention has also emphasized the linkages between rapid urbanization and disasters (11). Urbanization has become the dominant feature of human settlement patterns over the past century. More than half of the world’s current population lives in cities. By the year 2015 there are expected to be 60 megacities in the world, each with a population of 10 million or more people. Over the next several decades, the largest urban population changes are expected to occur in coastal areas, particularly in Asia and Africa (11).

The linkages between rapid urbanization and disasters have sometimes been described as reflexive: cities create their own risks by causing degradation of the local, regional, and global environments. High concentrations of resources and people within cities also mean that the economic, social, and environmental costs of extreme events are high in urban areas. Furthermore, these costs are likely to escalate as a result of growing populations in coastal cities, many of which are already highly vulnerable to sea-level rise, tsunamis, and other hazards.

Vulnerabilities – Mortality and damage

The private sector and their associated investments are also directly threatened by climate change. Ernst & Young describe climate change, coupled with its potential destabilizing affects linked to conflict and security, as the “greatest strategic risk facing the property and causality insurance industry” (12).

Concerning the economic and financial consequences of extreme events, many studies have explored the local and regional economic impacts of specific events, such as hurricanes, floods, earthquakes, heat waves, and wild fires. This research is generally focused on aggregate impacts including costs of business interruption, infrastructure damage and loss of business structures and productive capital, as well as on measures to reduce economic risks such as broader provision of private insurance, enforcement of building codes, and development of disaster preparedness plans. Limited attention has been directed toward the effects of extreme events on industries, businesses, and workers, including which industries are likely to expand or contract, which firms are likely to survive, and which types of workers are likely to gain or lose jobs.

Climate change may have a number of indirect effects as well. These may arise, for example, through changes in the costs of essential goods and services. Increasing water scarcity may lead to an increase in water prices; warmer temperatures are likely to influence demand for and the cost of energy for cooling; and climate-induced changes in the agricultural sector may drive up food prices. As with the direct effects of climate change, indirect effects will be unevenly distributed, with the burden falling most heavily on low-income households where a significant share of expenditures already goes towards food and energy, and where the opportunity costs of increased spending in these areas may lead to declining access to goods and services necessary to live dignified lives. Labor markets may also be affected, for example if production decreases associated with drought lead to a reduced demand for agricultural wage laborers.

Physical versus social vulnerability

A “physical vulnerability” approach emphasizes biogeophysical and technological interpretations that relate vulnerability to locations in high-risk areas (e.g., low-lying coastal areas), high concentrations of population and physical capital in small areas, a dependency on large-scale infrastructure projects, an increased risk of disease transmission due to crowded conditions, and location in fragile or vulnerable environments, such as deforested mountain slopes (13). This hazard-centered or impact-oriented paradigm focuses largely on the physical processes underlying vulnerability to climate change and disasters. Consequently, vulnerability reduction strategies often seek to control outcomes through monitoring and predicting, as well as through engineering projects and technological interventions that contain or reduce their effects (14).

A “social vulnerability” approach, in contrast, focuses on vulnerability as the result of an interplay among many contextual factors, including biophysical, social, economic, political, institutional, technological and cultural conditions that generate unequal exposure to risk and create differential capacities to respond to both shocks and long-term changes (15).

An individual or group’s vulnerability to climate change and climate-related disasters is thus influenced by the complex array of social, economic, political and environmental factors operating at a variety of levels that in combination affect vulnerability. Consequently, vulnerability is not evenly distributed across society, and some individuals, households, or groups are likely to be disproportionately affected by climate change or disasters.

In short, the possible effects of climate change extremes cannot be understood independently of larger social, economic and cultural changes. It is widely recognized within the disaster risk community that hazards themselves rarely create disasters, but instead it is the context in which the hazard occurs that contributes to disastrous outcomes (16).

This is relevant to climate change-related extreme events as well. Yet it is also important to recognize that the context in which climate extremes and hazards occur is constantly changing as the result of many factors, including rates of economic development and natural resource exploitation, urbanization, deforestation and land use changes. Among the many environmental and social processes that structure vulnerability, rising global food prices, warfare, corruption, trade dependency, macroeconomic policies, and a host of large-scale processes associated with globalization shape the social and economic entitlements that influence vulnerability (17).

There are also important path dependencies related to vulnerability; past processes such as colonization and war shape present insecurities, while ongoing processes such as climate change and changes to ecosystem services shape future insecurities.

Hazards and extreme events themselves can alter the context for economic and social development, which can in turn reduce the capacity to respond to future extremes. Cumulative effects of events such as hurricanes, floods, or droughts not only damage or destroy material assets and human lives, but they may also influence the capacity and resilience of individuals to recover their sense of well-being. Common emotional reactions after a disaster include shock, fear, grief, anger, guilt, shame, helplessness, numbness and sadness, which in combination with cognitive reactions such as confusion, indecisiveness, worry and difficulty concentrating, can make recovery a challenge for days, weeks, months, or years following a disaster.

Vulnerabilities - According to the German Advisory Council on Global Change (2007)

Climate-induced conflict constellations

The German Advisory Council on Global Change (WGBU) made an assessment on global security risks of climate change (38). WBGU considers that climate-induced inter-state wars are unlikely to occur. However, climate change could well trigger national and international distributional conflicts and intensify problems already hard to manage such as state failure, the erosion of social order, and rising violence. WBGU identifies four conflict constellations in which critical developments can be anticipated as a result of climate change and which may occur with similar characteristics in different regions of the world. “Conflict constellations” are defined as typical causal linkages at the interface of environment and society, whose dynamic can lead to social destabilization and, in the end, to violence.

1. Climate-induced degradation of freshwater resources.  1.1 billion people are currently without access to safe drinking water. The situation could worsen for hundreds of millions of people
2. Climate-induced decline in food production.More than 850 million people worldwide are currently undernourished. This situation is likely to worsen in future as a result of climate change, due to a drop in agricultural productivity, desertification, soil salinization and water scarcity.
3. Climate-induced increase in storm and flood disasters.The risk of natural disasters occurring in many cities and industrial regions in coastal zones will be further amplified by deforestation along the upper reaches of rivers, land subsidence in large urban areas and the ever greater spatial concentration of populations and assets.
4. Environmentally-induced migration.It can be assumed that the number of environmental migrants will substantially rise in future due to the impacts of climate change. Most environmental migration is initially likely to occur within national borders. Transboundary environmental migration will mainly take the form of south-south migration, but Europe and North America must also expect substantially increased migratory pressure from regions most at risk from climate change.

Six threats to international stability and security

In light of current knowledge about the social impacts of climate change, the German Advisory Council on Global Change (WGBU) identifies the following six key threats to international security and stability which will arise if climate change mitigation fails (38):

1. Possible increase in the number of weak and fragile states as a result of climate change.
2. Risks for global economic development.Unabated climate change is likely to result in substantially reduced rates of growth. This will increasingly limit the economic scope, at national and international level.
3. Risks of growing international distributional conflicts between the main drivers of climate change and those most affected.A key line of conflict in global politics in the 21st century would divide not only the industrialized and the developing countries, but also the rapidly growing newly industrializing countries and the poorer developing countries. The international community is ill-prepared at present for this type of distributional conflict.
4. The risk to human rights and the industrialized countries’ legitimacy as global governance actors.Unabated climate change could plunge the industrialized countries in particular into crises of legitimacy and limit their international scope for action.
5. Triggering and intensification of migration.The associated conflict potential is considerable, especially as “environmental migrants” are currently not provided for in international law.
6. Overstretching of classic security policy.A climate-induced increase in the number of weak and fragile states or even the destabilization of entire sub regions would overstretch conventional security policy.

Definition of water security according to the UNDP

Water security is about ensuring that every person has reliable access to enough safe water at an affordable price so as to lead a healthy, dignified and productive life, while maintaining the ecological systems that provide water and which also depend on water. If these conditions are not met, or if access to water is disrupted, people face acute human security risks transmitted through poor health and the disruption of livelihoods. Sufficient, safe, acceptable, physically accessible and affordable water for personal and domestic use are the five core attributes that represent the foundations for water security (39).

Adaptation strategies - According to the G7 members (2015)

The G7 members identified three key policy sectors to help strengthen the resilience of states and societies to climate-fragility risks (71):

1. Climate change adaptation programmes help countries anticipate the adverse effects of climate change and take action to prevent, minimize, and respond to its potential impacts.
2. Development and humanitarian aid programmes help states and populations build their economic, governance, and social capacities and improve their resilience to shocks.
3. Peacebuilding and conflict prevention programmes address the causes and effects of fragility and conflict by reducing tensions and creating an environment for sustainable peace. 


They proposed five specific action areas for a new multi-dimensional national and international cooperative approach for building resilience against climate-fragility risks (71):

1. Global Risk Assessment: G7 governments should establish a unified, shared, and accessible risk assessment methodology for identifying climate-fragility risks and generating actionable conclusions.
2. Food Security: In addition to developing resilient food systems, the risks posed by food insecurity can be miti- gated by better information, by keeping markets opera- ting during crisis and by market access.
3. Disaster Risk Reduction: Development partners should work together to invest in crisis prevention by integra- ting disaster risk reduction, peace building, and climate change adaptation.
4. Transboundary Water Disputes: A three-pronged approach can help ensure that transboundary waters become points of peaceful cooperation: stronger institutions, better dissemination of knowledge and encoura- ging cooperation between governments in transboundary river basins.
5. Building Local Resilience to Climate-Fragility Risks: G7 governments can embed support for resilience throughout their aid programmes and encourage others to do the same. 

Adaptation strategies - According to the European Commission (2008)

According to the European Commission (37), the EU should focus on:

• Enhancing capacities at the EU level: build up knowledge and assess the EU's own capacities, followed by an improvement in the prevention of, and preparedness for early responses to, disasters and conflicts. Monitoring and early warning needs to include in particular situations of state fragility and political radicalisation, tensions over resources and energy supplies, environmental and socio-economic stresses, threats to critical infrastructures and economic assets, border disputes, impact on human rights and potential migratory movements.
• EU multilateral leadership to promote global climate security: the EU needs to continue and strengthen its leadership towards an ambitious post-2012 agreement in 2009, including both mitigation and adaptation action by all countries as a key contribution to addressing climate security.
• Cooperation with third countries: greater prioritisation and enhanced support for climate change mitigation and adaptation, good governance, natural resource management, technology transfer, trans-boundary environmental cooperation (inter alia water and land), institutional strengthening and capacity building for crisis management.

Adaptation strategies - According to the German Advisory Council on Global Change (2007)

According to the German Advisory Council on Global Change (WGBU) a number of initiatives are needed (38):

1. Shaping global political change.In order to ensure the acceptance and, above all, the constructive participation of the ascendant new world powers China and India, a multilateral order is needed which is viewed as fair by all countries.
2. Reforming the United Nations.In general, WBGU is in favour of better coordinating the efforts of the relevant organizations and programmes under the auspices of the UN and significantly enhancing their role in the interests of prevention.
3. Ambitiously pursuing international climate policy.WBGU recommends the adoption, as an international standard, of a global temperature guard rail limiting the rise in near-surface air temperature to a maximum of 2°C relative to the pre-industrial value.
4. Implementing the energy turnaround in the EU.In order to be a credible negotiating partner within the climate process, the European Union should achieve its Kyoto commitments and set more far reaching and ambitious reduction targets for the future. In WBGU’s view, a 30 % reduction target for greenhouse gas emissions by 2020 compared with the 1990 baseline and an 80 % reduction target by 2050 are appropriate.
5. Developing mitigation strategies through partnerships. In development cooperation, path dependencies of emissions-intensive technologies should be avoided, and high priority should be granted to the promotion of sustainable energy systems in order to overcome energy poverty.
6. Supporting adaptation strategies for developing countries.Adapting water resources management to climate change and avoiding water crises, a.o. in order to avoid water conflicts, cooperation on transboundary water management should be encouraged for regions sharing waters. Focus should also be on gearing agriculture to climate change.
7. Stabilizing fragile states and weak states that are additionally threatened by climate change. Crisis prevention costs far less than crisis management at a later stage. Specifically, fragile states’ capacities to manage environmental risks must be maintained and reinforced, and if necessary re-established, even under difficult political and economic conditions.
8. Managing migration through cooperation and further developing international law.
9. Expanding global information and early warning systems.Both the gradual changes caused by climate change and the natural disasters which are expected to occur with increasing frequency could destabilize the affected regions and, in extreme cases, constitute a major risk factor for national and international security. Global information and early warning systems can therefore do much to mitigate these adverse effects and make a major contribution to conflict and crisis prevention.

WBGU anticipates that in the event of mitigation efforts failing, climate-induced security risks will begin to manifest themselves in various regions of the world from around 2025–2040. The key challenge is to take resolute climate policy action within the next 10–15 years, in order to avert the socioeconomic distortions and implications for international security that will otherwise intensify in subsequent decades (38).

Adaptation strategies - Vulnerability reduction

Vulnerability reduction is recognized as an important strategy for reducing disaster risks and minimizing the impacts of climate change. However, despite increased emphasis on the importance of social, political and economic contexts, climate change adaptation and traditional disaster risk management activities remain largely delinked from vulnerability reduction (18).

In fact, a synthesis of evaluation findings on humanitarian responses to natural disasters found relatively few examples of good practices related to vulnerability reduction (19). There tends to be, instead, a disproportionate emphasis on relief and recovery processes that prioritize a return to ‘normalcy,’ rather than focusing on the conditions that cause risk and vulnerability. In many cases, these ‘normal’ conditions are directly or indirectly contributing to risk and vulnerability (20).

Given these overlapping areas of expertise and empirical experience, there have been numerous calls for increased collaboration between the two communities. Yet strategies for disaster risk reduction and climate change adaptation have until now evolved largely in isolation from each other through different conceptual and institutional frameworks (21).

The disaster risk management community has gone through paradigm shifts from managing disasters by addressing the hazards, to understanding and addressing the underlying factors and vulnerabilities that turn hazards into disasters, culminating in the disaster risk reduction framework (22). The Hyogo Framework for Action (HFA) was adopted by 168 countries in 2005, and provides a technical and political agreement on the areas that needs to be addressed to reduce risk. The HFA presents five priorities for action:

1. ensure that disaster risk reduction is a national and a local priority with a strong institutional basis for implementation;
2. identify, assess and monitor disaster risks and enhance early warning;
3. use knowledge, innovation and education to build a culture of safety and resilience at all levels;
4. reduce the underlying risk factors;
5. strengthen disaster preparedness for effective response at all levels.

Climate change adaptation has a somewhat shorter history, emerging in the United Nations Framework Convention on Climate Change (UNFCCC) signed in 1992. However, the UNFCCC and the Kyoto protocol predominantly addressed climate change mitigation and policies and measures to reduce the emissions of greenhouse gases. It was not until quite recently that adaptation came to the forefront as a key concern within the UNFCCC (23). The Bali Action Plan (BAP), agreed upon at the UNFCCC Conference of Parties (COP) in Bali, puts adaptation on an equal footing with mitigation.

Disaster risk reduction and climate change adaptation must be closely linked to development

Enhancing collaboration across the disaster risk, climate change and development communities may be the most effective means of promoting sustainable adaptation to climate change. … Risk reduction and adaptation strategies must be carefully tailored to individual, household and community needs. Approaches that treat communities as homogeneous (i.e., able to adapt or reduce risks as a group) are prone to failure, as are adaptation and disaster risk reduction measures that do not explicitly and simultaneously address poverty (24).

Disaster risk reduction and climate change adaptation must address local needs

Engagement at the community level is underpinned by a reframing of vulnerable people not as passive victims but as capable of preventing disasters and adapting to climate change within their own communities. Bottom-up approaches promote locally-appropriate measures, empower people to change their own lives, and encourage greater ownership of disaster risk reduction and adaptation actions. Communications have been highlighted as extremely important, which suggests an emphasis on presenting knowledge in a community’s own language, through innovative media, and in understandable non-scientific terms.

Climate information must capture complexity and uncertainty to support adaptation and disaster risk reduction

Currently, the spatial resolution of many climate change projections is too coarse to enable effective disaster risk reduction at the local or regional scale. The gap between climate forecasts and projections and the needs of resource managers may pose some challenges to effective responses. … There is a need for a better understanding of complex and compound hazards, both from physical and social perspectives. The complexity of future extreme events, which are likely to be characterized by one or more hazard that is compounded by other factors (e.g. flooding combined with a cholera outbreak that coincides with an economic crisis), requires more robust and flexible disaster risk strategies and institutional responses than has been typically used in the past. … Communication about climate change needs to be made accessible in order to engage vulnerable people without compromising scientific credibility (25).

There are thresholds and limits to disaster risk reduction and adaptation

There are likely to be some thresholds and limits to the potential for disaster risk reduction and adaptation to enhance human security in the face of climate change. It has been noted that “the risk-reducing potential of planned adaptation is either very limited or very costly for some key vulnerabilities, such as loss of biodiversity, melting of mountain glaciers or disintegration of major ice sheets” (26)

In other words, there are absolute limits that are faced by many ecosystems and individual species in adapting to new climatic conditions, particularly given constraints of urban land use and conversion of natural habitats to agriculture; over-exploitation of resources such as fisheries; and other stresses such as pollution loading to terrestrial and marine environments (27). Hence there are major non-linearities and uncertainties related to climate change.

It is argued that “adaptation assessments need to consider not only the technical feasibility of certain adaptations but also the availability of required resources, the costs and side effects of adaptation, the knowledge about those adaptations, their timeliness, the incentives for the adaptation actors to actually implement them, and their compatibility with individual or cultural preferences” (26). Six broad categories have been discussed of limits to adaptation closely linked to the rate and magnitude of climate change, as well as associated key vulnerabilities: physical and ecological limits, technological limits, informational and cognitive limits, social and cultural limits, institutional political limits, and financial limits (28).

Links between migration and adaptation

Climate-related migration flows depend on the adaptive capacity of people living in areas exposed to increasing or intensifying climatic risks (87). Populations with strong adaptive capacity at the household and institutional levels are better able to cope with and adjust to climate hazards with minimal amounts of displacement and migration (88). Consequently, climate-related migration is less common in industrialized, urbanized countries than it is in low-income countries with large rural populations. Where migrants are able to access labour markets at the destination and remit money home, migration can be a successful form of adaptation (89). Take migration options away from people and their adaptive capacity may decline (84).

Adaptation - Costs

Financial barriers to both adaptation and disaster risk reduction have been highlighted, but primarily in policy documents around the international climate regime, rather than in scientific and economic literatures. The SBSTA body of the UNFCCC, the Stern Review, the World Bank, OECD, Oxfam and UNDP have estimated adaptation costs for developing countries (29).

The Stern Review presents the lowest estimate of USD 4 billion per year to adapt to climate change. The highest estimate is made by UNDP which estimates adaptation costs to USD 86-109 billion a year. An OECD study on the economics of adaptation demonstrates that these numbers, which have already been widely used in political statements and demand for more funds, should be handled with caution (30). … The important point is that the costs of adaptation are significant and hence there are real financial barriers, especially in developing countries, to implementing adaptation in a sustainable manner.

Adaptation - Peace building

Opportunities for integrating climate change into peacebuilding have been investigated (51). The opportunities refer to socio-economic recovery, politics and governance, security and rule of law, and human rights. More attention needs to be given to these opportunities in order to build resilience and reduce the likelihood of more daunting and costly challenges in the future. To make this work, three obstacles have to be overcome (51):

1. the lack of climate change tools and policies that can be easily introduced into typical peacebuilding programming;
2. the skepticism and complacency of the donor community (climate change constitutes an additional cost and is unlikely to generate quick benefits);
3. tensions between the objectives and timeframes of peacebuilding (the need to deliver immediate results) and those of climate change response (long-term thinking and planning).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Europe.

1. O’Brien et al. (2008)
2. Parry et al. (2007), in: O’Brien et al. (2008)
3. www.cred.be
4. UNISDR (2007), in O’Brien et al. (2008)
5. IFRC (2002), in: O’Brien et al. (2008)
6. Bouwer et al. (2007), in: O’Brien et al. (2008)
7. ICSU (2008), in: O’Brien et al. (2008)
8. Below et al. (2007), in: O’Brien et al. (2008)
9. Confalonieri et al. (2007), in: O’Brien et al. (2008)
10. ERM (2002), in: O’Brien et al. (2008)
11. Sanchez-Rodriguez et al. (2005), in: O’Brien et al. (2008)
12. Ernst & Young (2008), in: O’Brien et al. (2008)
13. Mitchell (1999), in: O’Brien et al. (2008)
14. Hilhorst (2004), in: O’Brien et al. (2008)
15. Cannon (1994); Bankoff et al. (2004); Roberts and Parks (2006), all in: O’Brien et al. (2008)
16. Wisner et al. (2004), in: O’Brien et al. (2008)
17. Adger and Kelly (1999), in: O’Brien et al. (2008)
18. Schipper (2008), in: O’Brien et al. (2008)
19. Stokke (2007), in: O’Brien et al. (2008)
20. Schipper (2008), in: O’Brien et al. (2008)
21. Yamin et al. (2005),in: O’Brien et al. (2008)
22. UNDP (2006), in: O’Brien et al. (2008)
23. UNFCCC (2007), in: O’Brien et al. (2008)
24. Tanner and Mitchell (2008), in: O’Brien et al. (2008)
25. Patt (2005), in: O’Brien et al. (2008)
26. Schneider et al. (2007), in: O’Brien et al. (2008)
27. Gordon et al. (2008), in: O’Brien et al. (2008)
28. Adger et al. (2007), in: O’Brien et al. (2008)
29. UNFCCC (2007); Stern Review (2006); World Bank (2006); Oxfam (2007); OECD (2008); UNDP (2007), all in: O’Brien et al. (2008)
30. OECD (2008), in: O’Brien et al. (2008)
31. Piguet (2008), in: O’Brien et al. (2008)
32. Brown (2008); Gleditsch (2007); Meze-Hausken (2000), all in: O’Brien et al. (2008)
33. Adger and Barnett (2005), in: O’Brien et al. (2008)
34. Wolf et al. (2006), in: O’Brien et al. (2008)
35. Ministry of the Environment of Norway (2009)
36. ACIA (2004)
37. European Commission (2008)
38. German Advisory Council on Global Change (2007)
39. UNDP (2009)
40. IPCC (2012)
41. Myers (2001); Christian Aid (2007), both in: IPCC (2012)
42. Brown (2008), in: IPCC (2012)
43. OCHA/IDMC (2009), in: IPCC (2012)
44. Castles (2002); Myers (2005); Thomalla et al. (2006); Barnett and Adger (2007); CIENS (2007); Dun and Gemenne (2008); Guzmán (2009); Morrissey (2009), all in: IPCC (2012)
45. UNDP (2009), in: IPCC (2012)
46. Kolmannskog (2008); Feng et al. (2010), both in: IPCC (2012)
47. Piguet (2008); UNDP (2009), both in: IPCC (2012)
48. UNISDR (2011), in: IPCC (2012)
49. Ahmed (2009); Brauch and Oswald Spring (2011), both in: IPCC (2012)
50. CAN Corporation (2007), in: IPCC (2012)
51. Matthew (2014)
52. German Advisory Council on Global Change (2008); McElroy and Baker (2012), both in: Matthew (2014)
53. Benjaminsen et al. (2012); Gartzke (2012); Slettebak (2012), all in: Matthew (2014)
54. United Nations General Assembly (2009), in: Matthew (2014)
55. Kallis et al. (2014)
56. Wolf (2009); Buhaug (2010), both in: Kallis et al. (2014)
57. Gleditsch (2012), in: Kallis et al. (2014)
58. Serageldin (2009), in: Kallis et al. (2014)
59. Selby and Hoffman (2013), in: Kallis et al. (2014)
60. Johnstone and Mazo (2011), in: Kallis et al. (2014)
61. Bruckner and Ciccone (2011), in: Kallis et al. (2014)
62. De Stefano et al. (2012), in: Kallis et al. (2014)
63. Hsiang et al. (2011), in: Hsiang and Burke (2014)
64. Hsiang and Burke (2014)
65. Salehyan and Hendrix (2014)
66. Martin (2009), in: IPCC (2014)
67. IPCC (2014)
68. Theisen et al. (2013), in: IPCC (2014)
69. Jägerskog and Swain (2016)
70. De Chatel (2014); Sowers et al. (2013); Weinthal et al. (2015), all in: Jägerskog and Swain (2016)
71. Rüttinger et al. (2015)
72. Hsiang et al. (2013); Burke et al. (2015), both in: Carleton and Hsiang (2016)
73. Carleton and Hsiang (2016) 
74. Feitelson and Tubi (2017)
75. Phillis et al. (2018)
76. Hedlund et al. (2018)
77. Davis et al. (2016), in: Hedlund et al. (2018)
78. Adams et al. (2018), in: Hendrix et al. (2018)
79. Abel et al. (2019)
80. Black et al. (2011), in: Abel et al. (2019)
81. Raleigh (2010), in: Abel et al. (2019)
82. Borderon et al. (2018), in: Abel et al. (2019)
83. Mach et al. (2019)
84. McLeman (2019)
85. Gemenne (2011), in: McLeman (2019)
86. Black et al. (2011); Warner and Afifi (2014); McLeman (2017), all in: McLeman (2019)
87. Tacoli (2009); Afifi et al. (2016); Black (2011), all in: McLeman (2019)
88. McLeman (2014); Gemenne and Blocher (2017), both in: McLeman (2019)
89. Adget et al. (2018), all in: McLeman (2019)
90. Falco et al. (2019)
91. Mastrorillo et al. (2016), in: Falco et al. (2019)
92. Black et al. (2011); Adger et al. (2014), both in: Falco et al. (2019)
93. Cai et al. (2016); Cattaneo and Peri (2016), both in: Falco et al. (2019)
94. Lobell et al. (2011); FAO (2017), both in: Falco et al. (2019)
95. Marchiori et al. (2012), in: Falco et al. (2019)
96. Feng et al. (2010), in: Falco et al. (2019)
97. Helman et al. (2020)
98. Tschumi and Zscheischler (2020)
99. Ide et al. (2020)
100. Sharifi et al. (2021)
101. Ercin et al. (2021)
102. Rikani et al. (2023)
103. Carleton and Hsiang (2016); Diffenbaugh and Burke (2019); Kalkuhl and Wenz (2020), all in: Rikani et al. (2023)
104. Diffenbaugh and Burke (2019), in: Rikani et al. (2023)
105. Buhaug et al. (2023)