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Effects of climate change are well documented and growing for Earth's natural environment and human societies. Changes to the climate system include an overall warming trend, changes to precipitation patterns, and more extreme weather. As the climate changes it impacts the natural environment with effects such as more intense forest fires, thawing permafrost, and desertification. These changes impact ecosystems and societies, and can become irreversible once tipping points are crossed. Climate activists are engaged in a range of activities around the world that seek to ameliorate these issues or prevent them from happening.
The effects of climate change vary in timing and location. Up until now the Arctic has warmed faster than most other regions due to climate change feedbacks. Surface air temperatures over land have also increased at about twice the rate they do over the ocean, causing intense heat waves. These temperatures would stabilize if greenhouse gas emissions were brought under control. Ice sheets and oceans absorb the vast majority of excess heat in the atmosphere, delaying effects there but causing them to accelerate and then continue after surface temperatures stabilize. Sea level rise is a particular long term concern as a result. The effects of ocean warming also include , ocean stratification, deoxygenation, and changes to ocean currents. The ocean is also acidifying as it absorbs carbon dioxide from the atmosphere.
The ecosystems most immediately threatened by climate change are in the mountains, , and the Arctic. Excess heat is causing environmental changes in those locations that exceed the ability of animals to adapt. Species are escaping heat by migrating towards the poles and to higher ground when they can. Sea level rise threatens coastal wetlands with coastal flooding. Decreases in soil moisture in certain locations can cause desertification and damage ecosystems like the Amazon Rainforest.IPCC, 2019: Summary for Policymakers. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems P.R.. At of warming, around 10% of species on land would become critically endangered.
Humans are vulnerable to climate change in many ways. Sources of food security and fresh water can be threatened by environmental changes. Human health can be impacted by weather extremes or by ripple effects like the spread of infectious diseases. Economic impacts include changes to agriculture, fisheries, and forestry. Higher temperatures will increasingly prevent outdoor labor in Tropics due to heat stress. Island nations and coastal cities may be inundated by rising sea levels. Some groups of people may be particularly at risk from climate change, such as the poor, children, and indigenous peoples. Industrialised countries, which have emitted the vast majority of CO2, have more resources to adapt to global warming than developing nations do. Cumulative effects and extreme weather events can lead to displacement and migration.
Scientists use several methods to predict the effects of human-caused climate change. One is to investigate past natural changes in climate. To assess changes in Earth's paleoclimate scientists have studied tree rings, , , and ocean and lake . These show that recent temperatures have surpassed anything in the last 2,000 years. The 20th century was the hottest in nearly 2,000 years, studies show , 25 July 2019 By the end of the 21st century, temperatures may increase to a level last seen in the mid-Pliocene. This was around 3 million years ago.Nicholls, R.J., P.P. Wong, V.R. Burkett, J.O. Codignotto, J.E. Hay, R.F. McLean, S. Ragoonaden and C.D. Woodroffe, 2007: Chapter 6: Coastal systems and low-lying areas. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 315-356. At that time, mean global temperatures were about warmer than pre-industrial temperatures. The global mean sea level was up to higher than it is today.Oppenheimer, M., B.C. Glavovic , J. Hinkel, R. van de Wal, A.K. Magnan, A. Abd-Elgawad, R. Cai, M. Cifuentes-Jara, R.M. DeConto, T. Ghosh, J. Hay, F. Isla, B. Marzeion, B. Meyssignac, and Z. Sebesvari, 2019: Chapter 4: Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate H.-O.. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 321–445. . The modern observed rise in temperature and concentrations has been rapid. Even abrupt geophysical events in Earth's history do not approach current rates.Allen, M.R., O.P. Dube, W. Solecki, F. Aragón-Durand, W. Cramer, S. Humphreys, M. Kainuma, J. Kala, N. Mahowald, Y. Mulugetta, R. Perez, M.Wairiu, and K. Zickfeld, 2018: Chapter 1: Framing and Context. In: Global Warming of 1.5 °C. An IPCC Special Report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty Masson-Delmotte,. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 49-92. .
How much the world warms depends on human greenhouse gas emissions and on how sensitive the climate is to greenhouse gases. The more carbon dioxide () is emitted in the 21st century the hotter the world will be by 2100. For a doubling of greenhouse gas concentrations, the global mean temperature would rise by about . If emissions of stopped abruptly and there was no use of negative emission technologies, the Earth's climate would not start moving back to its pre-industrial state. Temperatures would stay at the same high level for several centuries. After about a thousand years, 20% to 30% of human-emitted would remain in the atmosphere. The ocean and land would not have taken them. This would commit the climate to a warmer state long after emissions have stopped.
With current mitigation policies the temperature will be about 2.7 °C (2.0–3.6 °C) above pre-industrial levels by 2100. It would rise by if governments achieved all their unconditional pledges and targets. If all the countries that have set or are considering net-zero targets achieve them, the temperature will rise by around . There is a big gap between national plans and commitments and the actions that governments have taken around the world.
Evaporation and atmospheric moisture content increase as temperatures rise. Water vapor is a greenhouse gas, so this process is a self-reinforcing feedback.
The excess water vapour also gets caught up in storms. This makes them more intense, larger, and potentially longer-lasting. This in turn causes rain and snow events to become stronger and leads to increased risk of flooding. Extra drying worsens natural dry spells and droughts. This increases risk of and wildfires. Scientists have identified human activities as the cause of recent climate trends. They are now able to estimate the impact of climate change on extreme weather events using a process called extreme event attribution. For instance such research can look at historical data for a region and conclude that a specific heat wave was more intense due to climate change. In addition, the time shifts of the season onsets, changes in the length of the season durations have been reported in many regions of the world.Schwartz, M.D. and Reiter, B.E. (2000) Changes in North American spring. International Journal of Climatology, 20, 929–932.Hekmatzadeh, A.A., Kaboli, S. and Torabi Haghighi, A. (2020) New indices for assessing changes in seasons and in timing characteristics of air temperature. Theoretical and Applied Climatology, 140, 1247–1261. .Kozlov, M.V. and Berlina, N.G. (2002) Decline in the length of the summer season on the Kola Peninsula, Russia. Climatic Change, 54, 387–398Sparks, T.H. and Menzel, A. (2002) Observed changes in seasons: an overview. International Journal of Climatology, 22, 1715–1725.Aksu, H. (2022). A determination of season shifting across Turkey in the period 1965–2020. International Journal of Climatology, 42(16), 8232–8247. As a result of changes in climatic patterns and rising global temperatures, extreme weather events like heatwaves and heavy precipitation are occurring more frequently and with increasing severity.
Heatwaves over land have become more frequent and more intense in almost all world regions since the 1950s, due to climate change. Heat waves are more likely to occur simultaneously with droughts. Marine heatwaves are twice as likely as they were in 1980. Climate change will lead to more very hot days and fewer very cold days.IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change Stocker,. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US. There are fewer .
Experts can often attribute the intensity of individual heat waves to global warming. Some extreme events would have been nearly impossible without human influence on the climate system. A heatwave that would occur once every ten years before global warming started now occurs 2.8 times as often. Under further warming, heatwaves are set to become more frequent. An event that would occur every ten years would occur every other year if global warming reaches .
Hyperthermia is related to temperature. It also increases if humidity is higher. The wet-bulb temperature measures both temperature and humidity. Humans cannot adapt to a wet-bulb temperature above . This heat stress can kill people. If global warming is kept below , it will probably be possible to avoid this deadly heat and humidity in most of the tropics. But there may still be negative health impacts.
There is some evidence climate change is leading to a weakening of the polar vortex. This would make the jet stream more wavy. This would lead to outbursts of very cold winter weather across parts of Eurasia and North America and incursions of very warm air into the Arctic. Some studies found a weakening of the AMOC by about 15% since 1950, causing cold blob and warming in the Gulf Stream region. Climate change is expected to weaken AMOC in all emissions scenarios and, in some high emissions scenarios, can bring it to collapse. This can result in cooling of some parts of Europe by up to 30 degrees and warming in the southern hemisphere.
Climate change has increased contrasts in rainfall amounts between wet and dry seasons. Wet seasons are getting wetter and dry seasons are getting drier. In the northern high latitudes, warming has also caused an increase in the amount of snow and rain. In the Southern Hemisphere, the rain associated with the has shifted south. Changes in vary a lot. More monsoon systems are becoming wetter than drier. In Asia summer monsoons are getting wetter. The West African monsoon is getting wetter over the central Sahel, and drier in the far western Sahel.
Higher temperatures increase evaporation. This dries the soil and increases plant stress. Agriculture suffers as a result. This means even regions where overall rainfall is expected to remain relatively stable will experience these impacts. These regions include central and northern Europe. Without climate change mitigation, around one third of land areas are likely to experience moderate or more severe drought by 2100. Due to global warming droughts are more frequent and intense than in the past.
Several social factors may worsen the impact of droughts. These are increased water demand, population growth and urban expansion in many areas. Land restoration techniques, such as agroforestry, can help reduce the impact of droughts.Daniel Tsegai, Miriam Medel, Patrick Augenstein, Zhuojing Huang (2022) Drought in Numbers 2022 - restoration for readiness and resilience, United Nations Convention to Combat Desertification (UNCCD)
Weather conditions are raising the risks of wildfires. But the total area burnt by wildfires has decreased. This is mostly because savanna has been converted to croplands, so there are fewer trees to burn. Prescribed burning is an indigenous practice in the US and Australia. It can reduce wildfire burning.
The carbon released from wildfires adds to carbon dioxide in Earth's atmosphere and therefore contributes to the greenhouse effect. Climate models do not yet fully reflect this climate change feedback.
Earthquakes can be triggered by changes in the amount of stress on a fault in the Earth's crust. Strong rain, snow, drought and more pumping of groundwater by humans during droughts, can do it by increasing or reducing the weight of water on some pieces of the Earth's crust. So, as climate change will cause more extreme weather, it can induce more earthquakes. Glacier retreat reduce stress loads on Earth's crust underneath, creating glacial earthquakes. Glacial earthquakes in Greenland for example, peak in frequency in the summer months and are increasing over time, possibly in response to global warming.
Sea level rise can also create pressure on tectonic faults, increasing risk for earthquakes.
In Greenland, melting glaciers triggered a landslide, which caused a mega-tsunami in September 2023. Earthquake sensors around the world detected the resulting vibration, but the scale and duration of the event was unprecedented, so at first scientists failed to understand it. Further investigation revealed that the cause was the collapse of a 1,200-metre-high mountain peak into the remote Dickson Fjord on September 16, 2023, after the glacier below the mountain melted to a sufficient degree. The collapse into the fjord, in turn, launched a wave 200 metres high, which caused repeated movement of water back and forth in the fjord, generating seismic waves that were detectable worldwide for nine days.The Guardian, 12 Sept. 2024 "Entire Earth Vibrated for Nine Days After Climate-Triggered Mega-Tsunami "Landslide in Greenland Caused Unprecedented Seismic Event that Shows Impact of Global Heating, Say Scientists
Future melt of the West Antarctic ice sheet is potentially abrupt under a high emission scenario, as a consequence of a partial collapse.Collins M., M. Sutherland, L. Bouwer, S.-M. Cheong, T. Frölicher, H. Jacot Des Combes, M. Koll Roxy, I. Losada, K. McInnes, B. Ratter, E. Rivera-Arriaga, R.D. Susanto, D. Swingedouw, and L. Tibig, 2019: Chapter 6: Extremes, Abrupt Changes and Managing Risk. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate H.-O.. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 589–655. . Part of the ice sheet is grounded on bedrock below sea level. This makes it possibly vulnerable to the self-enhancing process of marine ice sheet instability. Marine ice cliff instability could also contribute to a partial collapse. But there is limited evidence for its importance. A partial collapse of the ice sheet would lead to rapid sea level rise and a local decrease in ocean salinity. It would be irreversible for decades and possibly even millennia. The complete loss of the West Antarctic ice sheet would cause over of sea level rise.
In contrast to the West Antarctic ice sheet, melt of the Greenland ice sheet is projected to take place more gradually over millennia. Sustained warming between (low confidence) and (medium confidence) would lead to a complete loss of the ice sheet. This would contribute to sea levels globally. The ice loss could become irreversible due to a further self-enhancing feedback. This is called the elevation-surface mass balance feedback. When ice melts on top of the ice sheet, the elevation drops. Air temperature is higher at lower altitudes, so this promotes further melting.
Sea ice in the Arctic has declined in recent decades in area and volume due to climate change. It has been melting more in summer than it refreezes in winter. The decline of sea ice in the Arctic has been accelerating during the early twenty-first century. It has a rate of decline of 4.7% per decade. It has declined over 50% since the first satellite records. Ice-free summers are expected to be rare at degrees of warming. They are set to occur at least once every decade with a warming level of .IPCC, 2018: Summary for Policymakers. In: Global Warming of 1.5 °C. An IPCC Special Report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty Masson-Delmotte,. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 3-24. . The Arctic will likely become ice-free at the end of some summers before 2050.Fox-Kemper, B., H.T. Hewitt, C. Xiao, G. Aðalgeirsdóttir, S.S. Drijfhout, T.L. Edwards, N.R. Golledge, M. Hemer, R.E. Kopp, G. Krinner, A. Mix, D. Notz, S. Nowicki, I.S. Nurhati, L. Ruiz, J.-B. Sallée, A.B.A. Slangen, and Y. Yu, 2021: Chapter 9: Ocean, Cryosphere and Sea Level Change. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Masson-Delmotte,. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US
Sea ice extent in Antarctica varies a lot year by year. This makes it difficult to determine a trend, and record highs and record lows have been observed between 2013 and 2023. The general trend since 1979, the start of the Satellite era, has been roughly flat. Between 2015 and 2023, there has been a decline in sea ice, but due to the high variability, this does not correspond to a significant trend.
The impacts of climate change on nature are likely to become bigger in the next few decades. The stresses caused by climate change, combine with other stresses on ecological systems such as land conversion, land degradation, harvesting, and pollution. They threaten substantial damage to unique ecosystems. They can even result in their complete loss and the extinction of species. This can disrupt key interactions between species within ecosystems. This is because species from one location do not leave the warming habitat at the same rate. The result is rapid changes in the way the ecosystem functions. Impacts include changes in regional rainfall patterns, earlier leafing of trees and plants over many regions, movements of species to higher latitudes and altitudes, changes in bird migrations, and shifting of the oceans' plankton and fish from cold- to warm-adapted communities.
These changes of land and ocean ecosystems have direct effects on human well-being.Cooley, S., D. Schoeman, L. Bopp, P. Boyd, S. Donner, D.Y. Ghebrehiwet, S.-I. Ito, W. Kiessling, P. Martinetto, E. Ojea, M.-F. Racault, B. Rost, and M. Skern-Mauritzen, 2022: Chapter 3: Oceans and Coastal Ecosystems and Their Services. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change H.-O.. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 379–550, doi:10.1017/9781009325844.005. For instance, ocean ecosystems help with coastal protection and provide food. Freshwater and land ecosystems can provide water for human consumption. Furthermore, these ecosystems can store carbon. This helps to stabilize the climate system.
Ocean acidification can harm marine organisms in various ways. Shell-forming organisms like are particularly vulnerable. Some phytoplankton and seagrass species may benefit. However, some of these are toxic to fish phytoplankton species. Their spread poses risks to fisheries and aquaculture. Fighting pollution can reduce the impact of acidification.
Coral reef are very sensitive to global warming and ocean acidification. Coral reefs provide a habitat for thousands of species. They provide ecosystem services such as coastal protection and food. But 70–90% of today's warm-water coral reefs will disappear even if warming is kept to .Hoegh-Guldberg, O., D. Jacob, M. Taylor, M. Bindi, S. Brown, I. Camilloni, A. Diedhiou, R. Djalante, K.L. Ebi, F. Engelbrecht, J.Guiot, Y. Hijioka, S. Mehrotra, A. Payne, S.I. Seneviratne, A. Thomas, R. Warren, and G. Zhou, 2018: Chapter 3: Impacts of 1.5 °C Global Warming on Natural and Human Systems. In: Global Warming of 1.5 °C. An IPCC Special Report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty Masson-Delmotte,. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 175-312. . Coral reefs are framework organisms. They build physical structures that form habitats for other sea creatures. Other framework organisms are also at risk from climate change. Mangroves and seagrass are considered to be at moderate risk from lower levels of global warming.
target="_blank" rel="nofollow"> 2017: Potential surprises – compound extremes and tipping elements. In: ''
target="_blank" rel="nofollow"> Climate Science Special Report: Fourth National Climate Assessment, Volume I'' Wuebbles,. U.S. Global Change Research Program, Washington, DC, USA, pp. 411-429, doi: 10.7930/J0GB227J There is already moderate risk of global tipping points at above pre-industrial temperatures. That becomes a high risk at . It is possible that some tipping points are close or have already been crossed. Examples are the West Antarctic and Greenland ice sheets, the Amazon rainforest, and warm-water coral reefs.
Tipping points are perhaps the most dangerous aspect of future climate change, potentially leading to irreversible impacts on society. A collapse of the Atlantic meridional overturning circulation would likely halve rainfall in India and lead to severe drops in temperature in Northern Europe. Many tipping points are interlinked such that triggering one may lead to a cascade of effects. This remains a possibility even well below of warming. A 2018 study states that 45% of environmental problems, including those caused by climate change, are interconnected. This increases the risk of a domino effect.
Further impacts may be irreversible, at least over the timescale of many human generations.Schneider, S.H., S. Semenov, A. Patwardhan, I. Burton, C.H.D. Magadza, M. Oppenheimer, A.B. Pittock, A. Rahman, J.B. Smith, A. Suarez and F. Yamin, 2007: Chapter 19: Assessing key vulnerabilities and the risk from climate change. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 779-810 This includes warming of the deep ocean and acidification. These are set to continue even when global temperatures stop rising. In biological systems, the extinction of species would be an irreversible impact. In social systems, unique may be lost. Climate change could make it more likely that endangered languages disappear.
Climate change is projected to negatively affect all four pillars of food security. It will affect how much food is available. It will also affect how easy food is to access through prices, food quality, and how stable the food system is. Climate change is already affecting the productivity of wheat and other staples.
In many areas, fishery catches are already decreasing because of global warming and changes in biochemical cycles. In combination with overfishing, warming waters decrease the amount of fish in the ocean. Per degree of warming, ocean biomass is expected to decrease by about 5%. Tropical and subtropical oceans are most affected, while there may be more fish in polar waters.
Between 1.5 and 2.5 billion people live in areas with regular water security issues. If global warming reaches , water insecurity would affect about twice as many people. Water resources are likely to decrease in most dry Subtropics regions and mid-latitudes. But they will increase in high latitudes. However, variable streamflow means even regions with increased water resources can experience additional short-term Water scarcity.Jiménez Cisneros, B.E., T. Oki, N.W. Arnell, G. Benito, J.G. Cogley, P. Döll, T. Jiang, and S.S. Mwakalila, 2014: Chapter 3: Freshwater resources. In: Climate Change 2014: Impacts,Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change Field,. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 229-269. In the arid regions of India, China, the US and Africa dry spells and drought are already affecting water availability.
Increased extreme heat exposure from climate change and the urban heat island effect threatens urban settlements. This is made worse by the loss of shade from Urban forest that cannot withstand the heat stress.
In 2019, the Crowther Lab from ETH Zurich paired the climatic conditions of 520 major cities worldwide with the predicted climatic conditions of cities in 2050. It found that 22% of the major cities would have climatic conditions that do not exist in any city today. For instance, 2050 London would have a climate similar to 2019 Melbourne in Australia. Athens and Madrid would be like Fez in Morocco. Nairobi in Kenya would be like Maputo in Mozambique. The Indian city Pune would be like Bamako in Mali and Bamako would be like Niamey in Niger. Brasilia would be like Goiania, both in Brazil. Cities of the future: visualizing climate change to inspire action, current vs future cities , Crowther Lab, Department für Umweltsystemwissenschaften, Institut für integrative Biologie, ETH Zürich, zugegriffen: 11 July 2019. Understanding climate change from a global analysis of city analogues, Bastin J-F, Clark E, Elliott T, Hart S, van den Hoogen J, Hordijk I, et al. (2019), PLOS ONE 14(7): e0217592, Crowther Lab, Department for Environmental Systems Science, Institut for Integrative Biology, ETH Zürich, 10 July 2019.
Small island developing states are especially vulnerable. They are likely to experience more intense storm surges, salt water intrusion and coastal destruction. Low-lying small islands in the Pacific, Indian, and Caribbean regions even risk permanent inundation. This would displace their population.
On the islands of Fiji, Tonga and western Samoa, migrants from outer islands inhabit low and unsafe areas along the coasts. The entire populations of small atoll nations such as Kiribati, Maldives, the Marshall Islands, and Tuvalu are at risk of being displaced.
This could raise issues of statelessness.
Some scientists describe the effects of climate change, with continuing increases in greenhouse gas emissions, as a "climate emergency" or "climate crisis". Scientists Around the World Declare 'Climate Emergency' , Smithsonian Magazine, 5 November 2019 Some researchers Climate change could pose 'existential threat' by 2050: report , CNN, 5 June 2019. and activists Greta Thunberg showed the world what it means to lead , The Guardian, 25 September 2019 describe them as an existential threat to civilization. Some define these threats under climate security. The consequences of climate change, and the failure to address it, can distract people from tackling its root causes. This leads to what some researchers have termed a "climate doom loop". Explained by Tigue, Kristoffer,
Migration due to climate and weather is usually within countries. But it is long-distance. Slow-onset disasters such as droughts and heat are more likely to cause long-term migration than weather disasters like floods. Migration due to desertification and reduced soil fertility is typically from rural areas in developing countries to towns and cities.
According to the Internal Displacement Monitoring Centre, extreme weather events displaced approximately 30 million people in 2020. Violence and wars displaced approximately 10 million in the same year. 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. This would be as they escape crop failures, water scarcity, and sea level rise. The study covered only Sub-Saharan Africa, South Asia, and Latin America. 143 Million People May Soon Become Climate Migrants , National Geographic, 19 March 2018
Climate change can increase conflict risks by causing tensions about scarce resources like food, water and land, by weakening state institutions, by reducing the for impoverished individuals to join armed groups, and by causing tensions related to (climate-induced) migration. Efforts to mitigate or adapt to climate change can also cause conflicts, for instance due to higher food and energy prices or when people are forcibly re-located from vulnerable areas.
Research has shown that climate change is not the most important conflict driver, and that it can only affect conflict risks under certain circumstances. Relevant context factors include agricultural dependence, a history of political instability, poverty, and the political exclusion of ethnic groups. Climate change has thus been described as a "threat multiplier". Yet, an impact of climate change on specific conflicts like the Syrian civil war or the Darfur genocide remains hard to prove. At the micro level, temperature volatility associated with climate change has likewise been found to act as a risk multiplier for short-term spikes in interpersonal violent crime.
As of October 2024, the possibility of societal collapse became more probable, the number of articles speaking about climate change and societal collapse increased sharply. Leading climate scientists emphasize that ""Climate change is a glaring symptom of a deeper systemic issue: ecological overshoot, which is an inherently unstable state that cannot persist indefinitely". To prevent it, they propose phase down fossil fuels, reduce methane emissions, overconsumption, and birth rate, switch to Plant-based diet, protect and restore and adopt an ecological, post-growth economics which includes climate justice. Climate change education should be integrated into core curriculums worldwide.
Economic impacts are bigger the more the temperature rises.* Scientists have compared impacts with warming of 1.5 °C (2.7 °F) and a level of 3.66 °C (6.59 °F). They use this higher figure to represent no efforts to stop emissions. They found that total damages at 1.5 °C were 90% less than at 3.66 °C. One study found that global GDP at the end of the century would be 3.5% less if warming is limited to . This study excludes the potential effect of tipping points. Another study found that excluding tipping points underestimates the global economic impact by a factor of two to eight. Another study found that a temperature rise of by 2050 would reduce global GDP by 2.5%–7.5%. By 2100 in this scenario the temperature would rise by . This could reduce global GDP by 30% in the worst case. A 2024 study, which checked the data from the last 120 years, found that climate change has already reduced welfare by 29% and further temperature rise will rise the number to 47%. The temperature rise during the years 1960–2019 alone has cut current GDP per capita by 18%. A 1 degree warming reduces global GDP by 12%. An increase of 3 degrees by 2100, will reduce capital by 50%. The effects are similar to experiencing the Great Depression permanently. The correct social cost of carbon according to the study is 1065 dollars per tonne of CO2.
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. These factors include population growth and increased wealth. Regional climatic factors also play a role. These include 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., p. 55, . The trend does suggest social systems are increasing vulnerable to climate change.
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. Higher operating temperatures make them less efficient. This reduces their output.Dr. Frauke Urban and Dr. Tom Mitchell 2011. Climate change, disasters and electricity generation . London: Overseas Development Institute and Institute of Development Studies Hydropower is affected by changes in the water cycle such as river flows. Diminished river flows can cause power shortages in areas that depend on hydroelectric power. Brazil relies on hydroelectricity. So it is particularly vulnerable. Rising temperatures, lower water flow, and changes in rainfall could reduce total energy production by 7% annually by the end of the century. Climate change affects oil and natural gas infrastructure. This is also vulnerable to the increased risk of disasters such as storms, cyclones, flooding and rising sea levels.
Global warming affects the insurance and financial services sectors. Insurance is an important tool to manage risks. But it is 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 said climate change could make home insurance unaffordable for households at or below average incomes.
It is possible that climate change has already begun to affect the shipping by impacting the Panama Canal. Lack of rainfall possibly linked to climate change reduced the number of ships passing through the canal per day, from 36 to 22 and by February 2024, it is expected to be 18.
target="_blank" rel="nofollow"> Climate from the World Meteorological Organization
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