myanmar which was submerged by cyclone nargis given high coastal population density, estimates of the number of people at risk of coastal flooding from climate-driven sea level rise varies from 190 million, to 300 million or even 640 million in a worst-case scenario related to the instability of the antarctic ice sheet. the most people affected are in the densely-populated and low-lying megadeltas of asia and africa. small islands developing states are especially vulnerable. they are expected to experience more intense storm surges, salt water intrusion, and coastal destruction. low-lying small islands in the pacific, indian, and caribbean regions are at risk of permanent inundation and population displacement. on the islands of fiji, tonga and western samoa, concentrations of migrants from outer islands inhabit low and unsafe areas along the coasts. small atoll nations such as kiribati, maldives, the marshall islands, and tuvalu are at risk of entire population displacement. a loss of these island could lead to issues of statelessness. vulnerability is increased by small size, isolation from other land, low financial resources, and lack of protective infrastructure. impacts on societies climate change impacts health, the availability of drinking water and food, inequality and economic growth. the effects of climate change are often interlinked and can exacerbate each other as well as existing vulnerabilities. some areas may become too hot for humans to live in. people in some areas may be displaced within their countries or to other countries due to climate-related changes or disasters. the effects of climate change, in combination with the sustained increases in greenhouse gas emissions, have led some scientists to call it a "climate emergency" or "climate crisis". some climate researchers and activists have called it an "existential threat to civilization". the consequences of climate change, and the failure to address it, can draw focus and resources from tackling its root causes, leading to what researchers have termed a "climate doom loop". displacement and migration climate change affects displacement of people in several ways. firstly, involuntary displacement may increase due to more frequent and severe weather-related disasters, which destroy homes and habitats. effects of climate change such as desertification and rising sea levels gradually erode livelihood and force communities to abandon traditional homelands. other forms of migration are adaptive and voluntary, based on individual or household decisions.: 1079 on the other hand, some households may fall (further) into poverty due to climate change, limiting their ability to move to areas less affected. migration due to climate and weather is usually national, but long-distance. slow-onset disasters such as droughts and heat are more likely to induce long-term migration than weather disasters like floods. migration due to desertification and reduced soil fertility is likely to be predominantly from rural areas in developing countries to towns and cities.: 109 according to the internal displacement monitoring centre, in 2020 approximately 30 million people were displaced by extreme weather events. in the same year, approximately 10 million were displaced by violence and wars; there may have been a contribution of climate change to these conflicts. in 2018, the world bank estimated that climate change will cause internal migration of between 31 and 143 million people by 2050, as they escape crop failures, water scarcity, and sea level rise. the study only included sub-saharan africa, south asia, and latin america. sea level rise at the marshall islands, reaching the edge of a village (from the documentary one word) conflict overlap between state fragility, extreme heat, and nuclear and biological catastrophic hazards climate change can worsen water conflicts and tensions over other limited resources. climate change also has the potential to cause large population dislocations and migration, which can also lead to increased tensions. however, factors other than climate change were judged to be substantially more important in affecting conflict over the last century. these factors include intergroup inequality and low socio-economic development. in some cases, climate change can even lead to more peaceful relationships between groups, as environmental problems require common policy to be developed. global warming has been described as a "threat multiplier". conditions in certain places make it more likely that climate change impacts conflict: ethnic exclusion, an economy dependent on agriculture, insufficient infrastructure, poor local governance, and low levels of development. a spike in wheat prices following crop losses from a period of drought may have contributed to the onset of the "arab spring" protests and revolutions in 2010. economic impacts business activities affected by climate changed as found in the european investment bank investment survey 2020 economic forecasts of the impact of global warming vary considerably, but are worse if there is only limited adaptation. economic modelling may underrate the impact of potentially catastrophic climatic changes. when estimating losses, economists choose a discount rate which determines how much one prefers to have a good or cash now compared to at a future date. choosing a high discount rate may understate economic losses, as losses for future generations weigh less heavily. total economic impacts increase for higher temperature rise. for instance, total damages are estimated to be 90% less if global warming is limited to 1.5 °c (2.7 °f) compared to 3.66 °c (6.59 °f), a warming level chosen to represent no mitigation. one study found a 3.5% reduction in global gdp by the end of the century if warming is limited to 3 °c (5.4 °f), excluding the potential effect of tipping points. another study noted that global economic impact is underestimated by a factor of two to eight when tipping points are excluded from consideration. in a study on a high-emission scenario, a temperature rise of 2 °c (3.6 °f) by 2050 would reduce global gdp by 2.5%–7.5%. by 2100 in this scenario the temperature would rise by 4 °c (7.2 °f), which could reduce the global gdp by 30% in the worst case. global losses reveal rapidly rising costs due to extreme weather events since the 1970s. socio-economic factors have contributed to the observed trend of global losses, such as population growth and increased wealth. part of the growth is also related to regional climatic factors, such as changes in precipitation and flooding events. it is difficult to quantify the relative impact of socio-economic factors and climate change on the observed trend. the trend does, however, suggest increasing vulnerability of social systems to climate change. economic inequality rich nations have done the most to fuel climate change. climate change has contributed towards global economic inequality. wealthy countries in colder regions have either felt little overall economic impact from climate change, or possibly benefited, whereas poor hotter countries very likely grew less than if global warming had not occurred. highly affected sectors economic sectors directly affected by weather are more impacted by climate change than other sectors. for instance, the agriculture, fisheries and forestry sectors are all heavily affected, but also the tourism and energy sectors. agriculture and forestry have suffered economic losses due to droughts and extreme heat, for instance in europe. if global warming surpasses 1.5 degrees, there may be limits to adaptation for existing tourism and for outdoor work. in the energy sector, thermal power plants depend on water to cool them. climate change can increase the likelihood of drought and fresh water shortages. in addition, higher operating temperatures reduces their efficiency and hence their output. hydropower is affected by changes in the water cycle such as river flows. the result of diminished river flow can be a power shortage in areas that depend heavily on hydroelectric power. brazil in particular, is vulnerable due to its reliance on hydroelectricity, as rising temperatures, lower water flow, and alterations in rainfall, could reduce total energy production by 7% annually by the end of the century. oil and natural gas infrastructure is affected by climate change and the increased risk of disasters such as storms, cyclones, flooding and rising sea levels. the insurance and financial services sectors are impacted by global warming. insurance is an important tool to manage risks, but often unavailable to poorer households. due to climate change, premiums are going up for certain types of insurance, such as flood insurance. poor adaptation to climate change further widens the gap between what people can afford and the costs of insurance, as risks increase. in 2019, munich re noted that climate change could cause home insurance to become unaffordable for households at or below average incomes. social impacts on vulnerable groups climate change does not impact people within communities in the same way. vulnerable groups such as women, the elderly, religious minorities and refugees may be more impacted by climate change than others. people living in poverty: climate change disproportionally affects poor people in low-income communities and developing countries around the world. those in poverty have a higher chance of experiencing the ill-effects of climate change, due to their increased exposure and vulnerability. a 2020 world bank paper estimated that between 32 million to 132 million additional people will be pushed into extreme poverty by 2030 due to climate change. women: climate change increases gender inequality, reduces women's ability to be financially independent, and has an overall negative impact on the social and political rights of women, especially in economies that are heavily based on agriculture. indigenous peoples: indigenous communities tend to rely more on the environment for food and other necessities, which makes them more vulnerable to disturbances in ecosystems. indigenous communities across the globe generally have economic disadvantages that are not as prevalent in non-indigenous communities, due to the oppression they have experienced. these disadvantages include less access to education and jobs and higher rates of poverty, which add to their vulnerability to climate change. children: the lancet review on health and climate change lists children among the worst-affected by global warming. children are 14–44 percent more likely to die from environmental factors. possibility of societal collapse climate change has long been described as a severe risk to humans. climate change as an existential threat has emerged as a key theme in the climate movement discourse; the theme is also used by people from small island nations. the topic has not been researched extensively. the research community on existential risks typically defines existential risks as threats that could cause the extinction of humanity or destroy the potential of intelligent life on earth. key risks of climate change do not fit that definition. however, some key climate risks do impact survivability. for instance, areas may become too hot to survive, or sea level rise makes it impossible to live at a specific location. this section is an excerpt from climate apocalypse § apocalyptic impacts of climate change and ecological breakdown. severe impacts of climate change can combine, including with climate-unrelated, concurrent risks such as worldwide pollution, fragility, resource depletion, political disenchantment, poverty or wealth inequality, and biotechnology risk, to result in a confluence of developments that cause a drastically aggravated impact on societies or humanity – such multiple concurrent crises are sometimes referred to as a "perfect storm". climate change may also be considered as a threat multiplier "which exacerbates existing trends, tensions, and instability". climate-related factors of a potential collapse may include famine (crop loss, drought), extreme weather (hurricanes, floods), war (caused by scarce resources) and conflict, systemic risk (relating to migration, famine, or conflict), and disease.