Climate change vulnerability is a concept that describes how strongly people or ecosystems are likely to be affected by climate change. Its formal definition is the "propensity or predisposition to be adversely affected" by climate change. It can apply to humans and also to natural systems (or ecosystems).[1] Issues around the capacity to cope and adapt are also part of this concept. Vulnerability is a component of climate risk. Vulnerability differs within communities and also across societies, regions, and countries. It can increase or decrease over time.
Vulnerability is higher in some locations than in others. Higher levels of vulnerability are found in areas with poverty, poor governance and conflict. Also, some livelihoods are more climate-sensitive than others. Smallholder farmers, pastoralists, and fishing communities are generally more vulnerable. Further drivers for vulnerability of people and ecosystems are unsustainable land and ocean use, inequity, marginalization, and historical and ongoing patterns of inequity such as colonialism, and governance.
There are many different notions of what it means to be vulnerable. However, an important distinction is between biophysical and social (or socioeconomic) vulnerability. Biophysical vulnerability is about the effects of physical climate hazards such as a heat wave or heavy rain events. Social vulnerability is about the underlying political, institutional, economic and social factors that set the scene for climate change. These factors matter for how and why people are affected, and they put some people and places more at risk than others. People who are more vulnerable include for example people with low incomes, indigenous peoples, women, children, the elderly.
Global vulnerability assessments use spatial mapping with aggregated data for the regional or national level. Tools for vulnerability assessment vary depending on the sector, the scale and the entity or system which is thought to vulnerable. For example, the Vulnerability Sourcebook is a guide for practical and scientific knowledge on vulnerability assessment. Climate vulnerability mapping helps to understand which areas are the most vulnerable. For example, vulnerability is generally a bigger problem for people in low-income countries than for those in high-income countries. Mapping can also help to communicate climate vulnerability to stakeholders. It is useful to carry out vulnerability assessments in advance of preparing local climate adaptation plans or risk management plans.
Climate change vulnerability is defined as the "propensity or predisposition to be adversely affected" by climate change. It can apply to humans but also to natural systems (ecosystems), and both are interdependent. Vulnerability is a component of climate risk. Vulnerability will be higher if the capacity to cope and adapt is low.
Climate vulnerability can include a wide variety of different meanings, situations, and contexts in climate change research. It has been a central concept in academic research and IPCC assessments since 2001.[2]
The concept was defined in the Third IPCC report (2001) as "the degree to which a system is susceptible to, and unable to cope with, adverse effects of climate change, including climate variability and extremes".[3] [4]
Early studies focused on biophysical vulnerability to climate change.[5] In other words, the effects of physical climate hazards such as a heat wave or heavy rain events. This direction of research was shaped by earlier natural hazards research and it emphasised physical changes and energy flows in the landscape. It aims to quantify and measure the impacts of an event on the environment and on people. Since (biophysical) vulnerability is interpreted here as the negative outcome of climate change on people or places, it is also sometimes referred to as 'outcome vulnerability'.[6] [7]
An alternative framing focuses on social dimensions of vulnerability that set the context in which climate change happens. These dimensions include the political, institutional, economic and social structures that interact with the physical climate changes. For example, water privatization might affect the ability of people to respond to drought. This direction of research was shaped by human security research and they focus on the current context or 'starting point' for the social and biophysical processes. They are sometimes also referred to as 'contextual vulnerability' approaches. Research in this area focuses on analysing the factors that "put people and places at risk and reduce capacity to respond".[8] See the section on 'Causes' below.
In the Fifth IPCC report, the social context was emphasized. It noted factors such as wealth and employment, access to technology and information, societal values and the role of institutions to resolve conflicts or develop relations among states as important.[9] Vulnerability was defined as a characteristic of people or places independently of physical events. The report included two additional definitions, one of contextual vulnerability and one of outcome vulnerability.
In the climate change context, exposure is defined as "the presence of people; livelihoods; species or ecosystems; environmental functions, services, and resources; infrastructure; or economic, social, or cultural assets in places and settings that could be adversely affected.".
In earlier definitions of vulnerability to climate change (in the Third IPCC report and Fourth IPCC report) vulnerability was defined as a function of exposure, sensitivity and adaptive capacity. This changed during the Fifth IPCC cycle. In this report, exposure was defined as one of the three interacting elements of climate risk, rather than as one of the external drivers of vulnerability. This change had two main implications. First, it means that vulnerability is understood as independent of exposure (and hazard) but is contextual. Second, it means that vulnerability assessment could focus on indicators for sensitivity and adaptive capacity to understand the current system weaknesses. For example, weaknesses such as the high ground slope of a farmland or marginalization of households in a community would make people or places sensitive to climate impacts. This makes it important to select the most hazard-relevant indicators for any vulnerability assessment. For example, to assess the vulnerability of traditional coastal fishing communities to sea surge, ‘distance of dwellings from sea’ and ‘elevation of dwellings from sea level’ would be hazard-relevant indicators.[10]
Climate change vulnerability has a wide variety of different meanings and uses of the term have varied and evolved over time. The main distinction is between biophysical and social (or socioeconomic) vulnerability:
Early studies focused on biophysical vulnerability to climate change. In other words, the effects of physical climate hazards such as a heat wave or heavy rain events. This direction of research was shaped by earlier natural hazards research and it emphasised physical changes and energy flows in the landscape. It aims to quantify and measure the impacts of an event on the environment and on people. It plays down the role of people themselves in managing these impacts. Since (biophysical) vulnerability is interpreted here as the negative outcome of climate change on people or places, it is also sometimes referred to as 'outcome vulnerability'.
Social vulnerability is a more people-centred, holistic perspective on how and why people are affected by climate change. Vulnerability of ecosystems and people to climate change is driven by certain unsustainable development patterns such as "unsustainable ocean and land use, inequity, marginalization, historical and ongoing patterns of inequity such as colonialism, and governance". Therefore, vulnerability is higher in some locations than in others. Certain aspects within a region increase vulnerability, for example poverty, governance challenges and violent conflict. Some types of livelihoods are regarded as particularly climate-sensitive, resulting in a higher level of climate change vulnerability. These include for example smallholder farmers, pastoralists and fishing communities.
At its basic level, a community that is economically vulnerable is one that is ill-prepared for the effects of climate change because it lacks the needed financial resources.[11] Preparing a climate resilient society will require huge investments in infrastructure, city planning, engineering sustainable energy sources, and preparedness systems. From a global perspective, it is more likely that people living at or below poverty will be affected the most by climate change and are thus the most vulnerable, because they will have the least amount of resource dollars to invest in resiliency infrastructure. They will also have the least amount of resource dollars for cleanup efforts after more frequently occurring natural climate change related disasters.[12]
Vulnerability for people of a certain gender or age can be caused by "systemic reproduction of historical legacies of inequality", for example as part of "(post)colonial, (post)apartheid, and poverty discrimination".[13] Social vulnerability of people can be related to aspects that make people different from one another (gender, class, race, age, etc.), and also the situational variables (where they live, their health, who lives with them in the household, how much they earn).
Geographic, or place-based vulnerability to climate change is an important dimension. The most geographically vulnerable locations to climate change are those that will be impacted by side effects of natural hazards, such as rising sea levels and by dramatic changes in ecosystem services, including access to food. Island nations are usually noted as more vulnerable but communities that rely heavily on a sustenance based lifestyle are also at greater risk.[14]
Around the world, climate change affects rural communities that heavily depend on their agriculture and natural resources for their livelihood. Increased frequency and severity of climate events disproportionately affects women, rural, dryland, and island communities.[15] This leads to more drastic changes in their lifestyles and forces them to adapt to this change. It is becoming more important for local and government agencies to create strategies to react to change and adapt infrastructure to meet the needs of those impacted. Various organizations work to create adaptation, mitigation, and resilience plans that will help rural and at risk communities around the world that depend on the earth's resources to survive.[16]
See also: Effects of climate change.
It has been estimated in 2021 that "approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change".
The vulnerability of ecosystems and people to climate change is not the same everywhere: there are marked differences among and within regions (see regions that are particularly vulnerable below). Vulnerability can also increase or decrease over time.
People who are more vulnerable to the effects of climate change than others include for example people with low incomes, indigenous peoples, women, children, the elderly. For example, when looking at the effects of climate change on human health, a report published in The Lancet found that the greatest impact tends to fall on the most vulnerable people such as the poor, women, children, the elderly, people with pre-existing health concerns, other minorities and outdoor workers.[17]
There can be "structural deficits related to social, economic, cultural, political, and institutional conditions" which would explain why some parts of the population are impacted more than others. This applies for example to climate-related risks to household water security for women in remote rural regions in Burkina Faso or the urban poor in sub-Saharan Africa.
Vulnerability can be reduced through climate change adaptation measures. For this reason, vulnerability is often framed in dialogue with climate change adaptation. Furthermore, measures that reduce poverty, gender inequality, bad governance and violent conflict would also reduce vulnerability. And finally, vulnerability would be reduced for everyone if decisive action on climate change was taken (climate change mitigation) so that the effects of climate change are less severe.
Equity is another essential component of vulnerability and is closely tied to issues of environmental justice and climate justice. As the most vulnerable communities are likely to be the most heavily impacted, a climate justice movement is coalescing in response. There are many aspects of climate justice that relate to vulnerability and resiliency. The frameworks are similar to other types of justice movements and include contractarianism which attempts to allocate the most benefits for the poor, utilitarianism which seeks to find the most benefits for the most people, egalitarianism which attempts to reduce inequality, and libertarianism which emphasizes a fair share of burden but also individual freedoms.[18]
Examples of climate justices approach can be seen by the work done by the United States government on both federal and local levels. On a federal level, The Environmental Protection Agency works toward the goals of Executive Order 12898,[19] Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations. E.O 12898 states the goals of implementing federal environmental justice initiatives that work toward aiding minority and low-income communities that suffer from disproportionate environmental or human health impacts. To alleviate environmental and health challenges within many American communities the U.S Environmental Protection Agency has implemented projects[20] region by region to ensure the development of environmental justice. These developments include but are not limited to population vulnerability, green space development locally as well as federally, and the reevaluation of environmentally disproportionate health burdens.
See also: Vulnerability assessment.
Vulnerability assessment is important because it provides information that can be used to develop management actions in response to climate change.[21] Climate change vulnerability assessments and tools are available at all scales. Macro-scale vulnerability assessment often uses indices. Modelling and participatory approaches are also in use. Global vulnerability assessments are based on spatial mapping using aggregated data for the regional or national level.[22]
Assessments are also done at sub-national and sectoral level, and also increasingly for cities on an urban district or neighbourhood scale. Vulnerability assessment is also done for local communities to evaluate where and how communities and livelihoods are vulnerable to climate change. Studies can vary widely in scope and scale— for example the World Bank and Ministry of Economy of Fiji commissioned a report for the whole country in 2017-18[23] while the Rochester, New York commissioned a much more local report for the city in 2018.[24] Or, for example, NOAA Fisheries commissioned Climate Vulnerability assessments for marine fishers in the United States.[25] In some cases vulnerability assessment is done in advance of preparing local climate adaptation plans or risk management plans.[26]
Global indices for climate change vulnerability include the ND-GAIN Country Index, which measures national climate vulnerability globally, INFORM Risk Index and the WorldRiskIndex, which include social vulnerability indices.[27] Indicator approaches are also used at national and sub-national levels. They use a composite index of many individual quantifiable indicators. To generate the index value or 'score', most often a simple average is calculated across a set of standardized values. However, sometimes weighting is done according what are thought to be the most important determinants of vulnerability.
Climate vulnerability tracking starts identifying the relevant information, preferably open access, produced by state or international bodies at the scale of interest. Then a further effort to make the vulnerability information freely accessible to all development actors is required.[28] Vulnerability tracking has many applications. It constitutes an indicator for the monitoring and evaluation of programs and projects for resilience and adaptation to climate change. Vulnerability tracking is also a decision making tool in regional and national adaptation policies.
Similarly as for climate risk assessment, tools for vulnerability assessment vary depending on the sector, the scale at which the study is being carried out, and the entity or system which is thought to vulnerable. Modelling and other participatory tools include WEAP for understanding water resource vulnerabilities and assessing adaptation options. The Vulnerability Sourcebook is a guide for practical and scientific knowledge on vulnerability assessment.[29] Climate vulnerability mapping is also used to understand which areas are the most geographically vulnerable. A systematic review published in 2019 found 84 studies focused on the use of mapping to communicate and do analysis of climate vulnerability.[30]
All regions of the world are vulnerable to climate change but to a different degree. With high confidence, researchers concluded in 2001 that developing countries would tend to be more vulnerable to climate change than developed countries.[31] Based on development trends in 2001, scientists have found that few developing countries would have the capacity to efficiently adapt to climate change.[32] This was partly due to their low adaptive capacity and the high costs of adaptation in proportion to their GDP.
The Arctic is extremely vulnerable to climate change. It was predicted in 2007 that there would be major ecological, sociological, and economic impacts in the region.[33] Among those being disproportionately impacted by issues regarding climate change have been the Indigenous peoples of the Arctic, such as the Inuit, Yupik, and Saami, who are particularly vulnerable.[34] Traditional livelihoods, including hunting, fishing, and reindeer herding, are threatened by changes in ice conditions, wildlife migration patterns, and habitat availability. Additionally, thawing permafrost can damage infrastructure and contaminate water sources, posing health and safety risks to communities.[35]
Small island Developing States are particularly vulnerable to climate change.[36] Partly this was attributed to their low adaptive capacity and the high costs of adaptation in proportion to their GDP. Climate change leads to more frequent and intense extreme weather events such as hurricanes, typhoons, and cyclones. Small islands are especially susceptible to these events, which can cause widespread destruction, loss of life, and economic setbacks.
In comparison, the climate vulnerability of Europe is lower than in developing countries. This was attributed to Europe's high GNP, stable growth, stable population, and well-developed political, institutional, and technological support systems.[37]