Impacts of 1.5°C of Global Warming on Natural and Human Systems. Who said-“It’ll change back again”? Answer is found in this REPORT.

Looking very strongly that future Generations will be killed by Climate Issues. And the Greed will be the prime cause. Greed will be Number One reason why they will die. What would a person need to see to make them believe? A long Article? A Picture? Or hasn’t the stinging, hurting heat seem eeriely more hurting today than 20 years ago? Doesn’t something seem oddly strange going on to the Planet? Can’t you see it? Feel it? Here, read about it-

https://www.ipcc.ch/sr15/download/

But World Leaders can shake their hands or wash their hands of the Deaths of People that will be coming. And like so many things, there really isn’t a Plan other than Talking about all of this stuff.

Oil Industry will fight tooth and nail to Keep Oil Use Number One. And they are a Powerful Lobby Group.

Legislators VOTE where the Money Donations are from. They ain’t stupid. They’ll take a million over $20 every time. But stupid people will send in that $20 every month.

Let’s face one Truth-we won’t be here to see the Worst of Global Warming and it’s affect on all things living. We won’t. And there’s a ton of Blame going on. But what can we do? Do your little part. Think before you use.

The Special Report on Global Warming of 1.5 °C (SR15)[note 1] was published by the Intergovernmental Panel on Climate Change (IPCC) on 8 October 2018.[1] The report, approved in IncheonSouth Korea, includes over 6,000 scientific references, and was prepared by 91 authors from 40 countries.[2] In December 2015, the 2015 United Nations Climate Change Conference called for the report.[2] The report was delivered at the United Nations’ 48th session of the IPCC to “deliver the authoritative, scientific guide for governments” to deal with climate change.[3]

Its key finding is that meeting a 1.5 °C (2.7 °F) target is possible but would require “deep emissions reductions”[4] and “rapid, far-reaching and unprecedented changes in all aspects of society.”[2] Furthermore, the report finds that “limiting global warming to 1.5 °C compared with 2 °C would reduce challenging impacts on ecosystems, human health and well-being” and that a 2 °C temperature increase would exacerbate extreme weather, rising sea levels and diminishing Arctic sea icecoral bleaching, and loss of ecosystems, among other impacts.[2] SR15 also has modelling that shows that, for global warming to be limited to 1.5 °C, “Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050.”[2] The reduction of emissions by 2030 and its associated changes and challenges, including rapid decarbonisation, was a key focus on much of the reporting which was repeated through the world.[5][6][7][8][9][10]

https://en.m.wikipedia.org/wiki/Special_Report_on_Global_Warming_of_1.5_%C2%B0C

In his 1 October 2018 opening statement at the 48th Session held in IncheonKoreaHoesung Lee, who has been Chair of the IPCC since 6 October 2015,[61] described this IPCC meeting as “one of the most important” in its history.[62][3] Debra Roberts, IPCC contributor called it the “largest clarion bell from the science community”. Roberts hopes “it mobilises people and dents the mood of complacency.”[63]

In a CBC interview, Paul Romer was asked if the Nobel Prize in economic sciences that he and William Nordhaus received shortly before the SR15 was released, was timed as a message. Romer said that he was optimistic that measures will be taken in time to avert climate catastrophe. Romer compared the angst and lack of political will in imposing a carbon tax to the initial angst surrounding the chlorofluorocarbon (CFC) ban and the positive impact it had on restoring the depleted ozone layer.[note 2][64] In giving the Nobel to Nordhaus and Romer, the Royal Swedish Academy of Sciences cited Nordhaus as saying “the most efficient remedy for problems caused by greenhouse gases is a global scheme of universally imposed carbon taxes”.[65]

Howard J. Herzog, a senior research engineer at the Massachusetts Institute of Technology, said that carbon capture and storage technologies, except reforestation, are problematic because of their impact on the environment, health and high cost.[66] In the article there is a link to another article that refers to a study published in the scientific journal “Nature Energy”. The study says that we can limit warming to 1.5 degrees without carbon capture and storage, by technological innovation and changing lifestyle.[67]

A 2021 study found that degrowth scenarios, where economic output either “declines” or declines in terms of contemporary economic metrics such as current GDP, have been neglected in considerations of 1.5 °C scenarios in the report, finding that investigated degrowth scenarios “minimize many key risks for feasibility and sustainability compared to technology-driven pathways” with a core problem of such being feasibility in the context of contemporary decision-making of politics and globalized rebound- and relocation-effects.[68][69][70]

Politics

Australia

Prime Minister Scott Morrison emphasised that the report was not specifically for Australia but for the whole world.[71] Energy Minister Angus Taylor said the Government would “not be distracted” by the IPCC report saying “A debate about climate change and generation technologies in 2050 won’t bring down current power prices for Australian households and small businesses.”[71] Environment Minister Melissa Price said that scientists are “drawing a very long bow” to say coal should be phased out by 2050 and supported new coal-fired power stations pledging not to legislate the Paris targets.[72][73] Australia is not on track to meet the commitments under Paris agreement according to modelling conducted by ClimateWorks Australia.[74][75][76]

Canada

Canadian Environment Minister Catherine McKenna acknowledged that the SR15 report would say Canada is not “on track” for 1.5 °C.[77] Canada will not be implementing new plans but it will continue to move forward on a “national price on carbon, eliminating coal-fired power plants, making homes and businesses more energy-efficient, and investing in clean technologies and renewable energy”. In response to a question on the sense of urgency of the SR15 report during a 9 October interview on CBC News‘s Power and Politics Andrew Scheer, the Leader of the Opposition, promised that they are putting forward a “comprehensive plan to reduce CO2 without imposing a carbon tax” which Scheer said “raised costs without actually reducing emissions.”[78]

European Union

According to The New York Times, the European Union indicated it might add more ambitious reform goals centered around reducing emissions.[79] On 9 October, the Council of the European Union presented their response to SR15 and their position for the Katowice Climate Change Conference of the Parties (COP 24) held in Poland in December 2018.[80] Their environment ministers noted recent progress in legislation to reduce greenhouse gas emissions.[80][note 3]

India

The Centre for Science and Environment said the repercussions for developing countries such as India, would be “catastrophic” at 2 °C warming and that the impact even at 1.5 °C described in SR15 is much greater than anticipated. Crop yields would decline and poverty would increase.[81]

New Zealand

The Minister for Climate Change James Shaw said that the Report “has laid out a strong case for countries to make every effort to limit temperature rise to 1.5° Celsius above pre-industrial levels. … The good news is that the IPCC’s report is broadly in line with this Government’s direction on climate change and it’s highly relevant to the work we are doing with the Zero Carbon Bill.”[82]

United States

President Donald Trump said that he had received the report, but wanted to learn more about those who “drew it” before offering conclusions.[10] In an interview with ABC’s “This Week” the director of the National Economic CouncilLarry Kudlow, stated, “personally, I think the UN study is way too difficult,” and that the authors “overestimate” the likelihood for environmental disasters.[83] Since the publication Trump stated in an interview on 60 Minutes that he didn’t know that climate change is manmade and that “it’ll change back again”, the scientists who say it’s worse than ever have “a very big political agenda” and that “we have scientists that disagree with [manmade climate change].”[84]

COP24

The governments of four countries (the gas/oil-producers USA, Russia, Saudi Arabia and Kuwait) blocked a proposal to welcome the Intergovernmental Panel on Climate Change’s (IPCC) Special Report on Global Warming of 1.5 °C at the 2018 United Nations Climate Change Conference (COP24).[85]

Other

The “Special Report on Global Warming of 1.5 °C” (SR15) is cited by Greta Thunberg in her speeches “Wherever I Go I Seem to Be Surrounded by Fairy Tales” (United States Congress, Washington DC, 18 September 2019) and “We Are the Change and Change Is Coming” (Week For Future, Climate Strike, Montreal, 27 September 2019), both published in the second edition of No One Is Too Small to Make a Difference.

At the 2019 World Economic Forum, the head of the International Monetary FundKristalina Georgieva, said that: “The big eye opener [into climate change and its effects] was when last year I read [the SR15] IPCC report. I tell you, I could not sleep that night. […] What have we done?”.[86]

Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth’s climate system and caused change on a global scale.[2]Average surface air temperatures from 2011 to 2020 compared to a baseline average from 1951 to 1980 (Source: NASA)Observed temperature from NASA versus the 1850–1900 average as a pre-industrial baseline. The main driver for increased global temperatures in the industrial era is human activity, with natural forces adding variability.[1]

The largest driver of warming is the emission of gases that create a greenhouse effect, of which more than 90% are carbon dioxide (CO
2) and methane.[3] Fossil fuel burning (coaloil, and natural gas) for energy consumption is the main source of these emissions, with additional contributions from agriculture, deforestation, and manufacturing.[4] The human cause of climate change is not disputed by any scientific body of national or international standing.[5] Temperature rise is accelerated or tempered by climate feedbacks, such as loss of sunlight-reflecting snow and ice cover, increased water vapour (a greenhouse gas itself), and changes to land and ocean carbon sinks.

Temperature rise on land is about twice the global average increase, leading to desert expansion and more common heat waves and wildfires.[6] Temperature rise is also amplified in the Arctic, where it has contributed to melting permafrostglacial retreat and sea ice loss.[7] Warmer temperatures are increasing rates of evaporation, causing more intense storms and weather extremes.[8] Impacts on ecosystems include the relocation or extinction of many species as their environment changes, most immediately in coral reefs, mountains, and the Arctic.[9] Climate change threatens people with food insecuritywater scarcity, flooding, infectious diseases, extreme heat, economic losses, and displacement. These human impacts have led the World Health Organization to call climate change the greatest threat to global health in the 21st century.[10] Even if efforts to minimise future warming are successful, some effects will continue for centuries, including rising sea levels, rising ocean temperatures, and ocean acidification.[11]Energy flows between space, the atmosphere, and Earth’s surface. Current greenhouse gas levels are causing a radiative imbalance of about 0.9 W/m2.[12]

Many of these impacts are already felt at the current level of warming, which is about 1.2 °C (2.2 °F).[13][14] The Intergovernmental Panel on Climate Change (IPCC) has issued a series of reports that project significant increases in these impacts as warming continues to 1.5 °C (2.7 °F) and beyond.[15] Additional warming also increases the risk of triggering critical thresholds called tipping points.[16] Responding to these impacts involves both mitigation and adaptation.[17] Mitigation – limiting climate change – consists of reducing greenhouse gas emissions and removing them from the atmosphere.[17] Methods to achieve this include the development and deployment of low-carbon energy sources such as wind and solar, a phase-out of coal, enhanced energy efficiency, and forest preservation. Adaptation consists of adjusting to actual or expected climate,[17] such as through improved coastline protection, better disaster managementassisted colonisation, and the development of more resistant crops. Adaptation alone cannot avert the risk of “severe, widespread and irreversible” impacts.[18]

Under the 2015 Paris Agreement, nations collectively agreed to keep warming “well under 2.0 °C (3.6 °F)” through mitigation efforts. However, with pledges made under the Agreement, global warming would still reach about 2.8 °C (5.0 °F) by the end of the century.[19] Limiting warming to 1.5 °C (2.7 °F) would require halving emissions by 2030 and achieving near-zero emissions by 2050.[20]

Before the 1980s, when it was unclear whether warming by greenhouse gases would dominate aerosol-induced cooling, scientists often used the term inadvertent climate modification to refer to humankind’s impact on the climate. In the 1980s, the terms global warming and climate change were popularised, the former referring only to increased surface warming, the latter describing the full effect of greenhouse gases on the climate.[21] Global warming became the most popular term after NASA climate scientist James Hansen used it in his 1988 testimony in the U.S. Senate.[22] In the 2000s, the term climate change increased in popularity.[23] Global warming usually refers to human-induced warming of the Earth system, whereas climate change can refer to natural as well as anthropogenic change.[24] The two terms are often used interchangeably.[25]

Various scientists, politicians and media figures have adopted the terms climate crisis or climate emergency to talk about climate change, while using global heating instead of global warming.[26] The policy editor-in-chief of The Guardian explained that they included this language in their editorial guidelines “to ensure that we are being scientifically precise, while also communicating clearly with readers on this very important issue”.[27] Oxford Dictionary chose climate emergency as its word of the year in 2019 and defines the term as “a situation in which urgent action is required to reduce or halt climate change and avoid potentially irreversible environmental damage resulting from it”.[28]

Drivers of recent temperature rise

Main article: Attribution of recent climate changeContributors to climate change in 2011, as reported in the fifth IPCC assessment report

The climate system experiences various cycles on its own which can last for years (such as the El Niño–Southern Oscillation), decades or even centuries.[52] Other changes are caused by an imbalance of energy that is “external” to the climate system, but not always external to the Earth.[53] Examples of external forcings include changes in the composition of the atmosphere (e.g. increased concentrations of greenhouse gases), solar luminosityvolcanic eruptions, and variations in the Earth’s orbit around the Sun.[54]

To determine the human contribution to climate change, known internal climate variability and natural external forcings need to be ruled out. A key approach is to determine unique “fingerprints” for all potential causes, then compare these fingerprints with observed patterns of climate change.[55] For example, solar forcing can be ruled out as a major cause because its fingerprint is warming in the entire atmosphere, and only the lower atmosphere has warmed, as expected from greenhouse gases (which trap heat energy radiating from the surface).[56] Attribution of recent climate change shows that the primary driver is elevated greenhouse gases, but that aerosols also have a strong effect.[57]

Greenhouse gases

Main articles: Greenhouse gasGreenhouse gas emissionsGreenhouse effect, and Carbon dioxide in Earth’s atmosphereCO
2 concentrations over the last 800,000 years as measured from ice cores (blue/green) and directly (black)

The Earth absorbs sunlight, then radiates it as heat. Greenhouse gases in the atmosphere absorb and reemit infrared radiation, slowing the rate at which it can pass through the atmosphere and escape into space.[58] Before the Industrial Revolution, naturally-occurring amounts of greenhouse gases caused the air near the surface to be about 33 °C (59 °F) warmer than it would have been in their absence.[59][60] While water vapour (~50%) and clouds (~25%) are the biggest contributors to the greenhouse effect, they increase as a function of temperature and are therefore considered feedbacks. On the other hand, concentrations of gases such as CO
2 (~20%), tropospheric ozone,[61] CFCs and nitrous oxide are not temperature-dependent, and are therefore considered external forcings.[62]

Human activity since the Industrial Revolution, mainly extracting and burning fossil fuels (coaloil, and natural gas),[63] has increased the amount of greenhouse gases in the atmosphere, resulting in a radiative imbalance. In 2018, the concentrations of CO
2 and methane had increased by about 45% and 160%, respectively, since 1750.[64] These CO
2 levels are much higher than they have been at any time during the last 800,000 years, the period for which reliable data have been collected from air trapped in ice cores.[65] Less direct geological evidence indicates that CO
2 values have not been this high for millions of years.[66]The Global Carbon Project shows how additions to CO
2 since 1880 have been caused by different sources ramping up one after another.

Global anthropogenic greenhouse gas emissions in 2018, excluding those from land use change, were equivalent to 52 billion tonnes of CO
2. Of these emissions, 72% was actual CO
2, 19% was methane, 6% was nitrous oxide, and 3% was fluorinated gases.[3] CO
2 emissions primarily come from burning fossil fuels to provide energy for transport, manufacturing, heating, and electricity.[67] Additional CO
2 emissions come from deforestation and industrial processes, which include the CO
2 released by the chemical reactions for making cementsteelaluminum, and fertiliser.[68] Methane emissions come from livestock, manure, rice cultivation, landfills, wastewater, coal mining, as well as oil and gas extraction.[69] Nitrous oxide emissions largely come from the microbial decomposition of inorganic and organic fertiliser.[70] From a production standpoint, the primary sources of global greenhouse gas emissions are estimated as: electricity and heat (25%), agriculture and forestry (24%), industry and manufacturing (21%), transport (14%), and buildings (6%).[71]

Despite the contribution of deforestation to greenhouse gas emissions, the Earth’s land surface, particularly its forests, remain a significant carbon sink for CO
2. Natural processes, such as carbon fixation in the soil and photosynthesis, more than offset the greenhouse gas contributions from deforestation. The land-surface sink is estimated to remove about 29% of annual global CO
2 emissions.[72] The ocean also serves as a significant carbon sink via a two-step process. First, CO
2 dissolves in the surface water. Afterwards, the ocean’s overturning circulation distributes it deep into the ocean’s interior, where it accumulates over time as part of the carbon cycle. Over the last two decades, the world’s oceans have absorbed 20 to 30% of emitted CO
2.[73]

Aerosols and clouds

Air pollution, in the form of aerosols, not only puts a large burden on human health, but also affects the climate on a large scale.[74] From 1961 to 1990, a gradual reduction in the amount of sunlight reaching the Earth’s surface was observed, a phenomenon popularly known as global dimming,[75] typically attributed to aerosols from biofuel and fossil fuel burning.[76] Aerosol removal by precipitation gives tropospheric aerosols an atmospheric lifetime of only about a week, while stratospheric aerosols can remain in the atmosphere for a few years.[77] Globally, aerosols have been declining since 1990, meaning that they no longer mask greenhouse gas warming as much.[78]

In addition to their direct effects (scattering and absorbing solar radiation), aerosols have indirect effects on the Earth’s radiation budget. Sulfate aerosols act as cloud condensation nuclei and thus lead to clouds that have more and smaller cloud droplets. These clouds reflect solar radiation more efficiently than clouds with fewer and larger droplets.[79] This effect also causes droplets to be more uniform in size, which reduces the growth of raindrops and makes clouds more reflective to incoming sunlight.[80] Indirect effects of aerosols are the largest uncertainty in radiative forcing.[81]

While aerosols typically limit global warming by reflecting sunlight, black carbon in soot that falls on snow or ice can contribute to global warming. Not only does this increase the absorption of sunlight, it also increases melting and sea-level rise.[82] Limiting new black carbon deposits in the Arctic could reduce global warming by 0.2 °C (0.36 °F) by 2050.[83]

Changes of the land surface

The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy.[84]

Humans change the Earth’s surface mainly to create more agricultural land. Today, agriculture takes up 34% of Earth’s land area, while 26% is forests, and 30% is uninhabitable (glaciers, deserts, etc.).[85] The amount of forested land continues to decrease, largely due to conversion to cropland in the tropics.[86] This deforestation is the most significant aspect of land surface change affecting global warming. The main causes of deforestation are: permanent land-use change from forest to agricultural land producing products such as beef and palm oil (27%), logging to produce forestry/forest products (26%), short term shifting cultivation (24%), and wildfires (23%).[87]

In addition to affecting greenhouse gas concentrations, land-use changes affect global warming through a variety of other chemical and physical mechanisms. Changing the type of vegetation in a region affects the local temperature, by changing how much of the sunlight gets reflected back into space (albedo), and how much heat is lost by evaporation. For instance, the change from a dark forest to grassland makes the surface lighter, causing it to reflect more sunlight. Deforestation can also contribute to changing temperatures by affecting the release of aerosols and other chemical compounds that influence clouds, and by changing wind patterns.[88] In tropic and temperate areas the net effect is to produce significant warming, while at latitudes closer to the poles a gain of albedo (as forest is replaced by snow cover) leads to an overall cooling effect.[88] Globally, these effects are estimated to have led to a slight cooling, dominated by an increase in surface albedo.[89]

Solar and volcanic activity

Further information: Solar activity and climate

Physical climate models are unable to reproduce the rapid warming observed in recent decades when taking into account only variations in solar output and volcanic activity.[90] As the Sun is the Earth’s primary energy source, changes in incoming sunlight directly affect the climate system.[81] Solar irradiance has been measured directly by satellites,[91] and indirect measurements are available from the early 1600s.[81] There has been no upward trend in the amount of the Sun’s energy reaching the Earth.[92] Further evidence for greenhouse gases being the cause of recent climate change come from measurements showing the warming of the lower atmosphere (the troposphere), coupled with the cooling of the upper atmosphere (the stratosphere).[93] If solar variations were responsible for the observed warming, warming of both the troposphere and the stratosphere would be expected, but that has not been the case.[56]

Explosive volcanic eruptions represent the largest natural forcing over the industrial era. When the eruption is sufficiently strong (with sulfur dioxide reaching the stratosphere) sunlight can be partially blocked for a couple of years, with a temperature signal lasting about twice as long. In the industrial era, volcanic activity has had negligible impacts on global temperature trends.[94] Present-day volcanic CO2 emissions are equivalent to less than 1% of current anthropogenic CO2 emissions.[95]

Climate change feedback

Main articles: Climate change feedback and Climate sensitivitySea ice reflects 50% to 70% of incoming solar radiation while the dark ocean surface only reflects 6%, so melting sea ice is a self-reinforcing feedback.[96]

The response of the climate system to an initial forcing is modified by feedbacks: increased by self-reinforcing feedbacks and reduced by balancing feedbacks.[97] The main reinforcing feedbacks are the water-vapour feedback, the ice–albedo feedback, and probably the net effect of clouds.[98] The primary balancing feedback to global temperature change is radiative cooling to space as infrared radiation in response to rising surface temperature.[99] In addition to temperature feedbacks, there are feedbacks in the carbon cycle, such as the fertilizing effect of CO
2 on plant growth.[100] Uncertainty over feedbacks is the major reason why different climate models project different magnitudes of warming for a given amount of emissions.[101]

As air gets warmer, it can hold more moisture. After initial warming due to emissions of greenhouse gases, the atmosphere will hold more water. As water vapour is a potent greenhouse gas, this further heats the atmosphere.[98] If cloud cover increases, more sunlight will be reflected back into space, cooling the planet. If clouds become more high and thin, they act as an insulator, reflecting heat from below back downwards and warming the planet.[102] Overall, the net cloud feedback over the industrial era has probably exacerbated temperature rise.[103] The reduction of snow cover and sea ice in the Arctic reduces the albedo of the Earth’s surface.[104] More of the Sun’s energy is now absorbed in these regions, contributing to amplification of Arctic temperature changes.[105] Arctic amplification is also melting permafrost, which releases methane and CO
2 into the atmosphere.[106]

Around half of human-caused CO
2 emissions have been absorbed by land plants and by the oceans.[107] On land, elevated CO
2 and an extended growing season have stimulated plant growth. Climate change increases droughts and heat waves that inhibit plant growth, which makes it uncertain whether this carbon sink will continue to grow in the future.[108] Soils contain large quantities of carbon and may release some when they heat up.[109] As more CO
2 and heat are absorbed by the ocean, it acidifies, its circulation changes and phytoplankton takes up less carbon, decreasing the rate at which the ocean absorbs atmospheric carbon.[110] Climate change can increase methane emissions from wetlands, marine and freshwater systems, and permafrost.[111]

Future warming and the carbon budget

Further information: Carbon budgetClimate model, and Carbon cycleAverage climate model projections for 2081–2100 relative to 1986–2005, under low and high emission scenarios

Future warming depends on the strengths of climate feedbacks and on emissions of greenhouse gases.[112] The former are often estimated using various climate models, developed by multiple scientific institutions.[113] A climate model is a representation of the physical, chemical, and biological processes that affect the climate system.[114] Models include changes in the Earth’s orbit, historical changes in the Sun’s activity, and volcanic forcing.[115] Computer models attempt to reproduce and predict the circulation of the oceans, the annual cycle of the seasons, and the flows of carbon between the land surface and the atmosphere.[116] Models project different future temperature rises for given emissions of greenhouse gases; they also do not fully agree on the strength of different feedbacks on climate sensitivity and magnitude of inertia of the climate system.[117]

The physical realism of models is tested by examining their ability to simulate contemporary or past climates.[118] Past models have underestimated the rate of Arctic shrinkage[119] and underestimated the rate of precipitation increase.[120] Sea level rise since 1990 was underestimated in older models, but more recent models agree well with observations.[121] The 2017 United States-published National Climate Assessment notes that “climate models may still be underestimating or missing relevant feedback processes”.[122]

Various Representative Concentration Pathways (RCPs) can be used as input for climate models: “a stringent mitigation scenario (RCP2.6), two intermediate scenarios (RCP4.5 and RCP6.0) and one scenario with very high [greenhouse gas] emissions (RCP8.5)”.[123] RCPs only look at concentrations of greenhouse gases, and so do not include the response of the carbon cycle.[124] Climate model projections summarised in the IPCC Fifth Assessment Report indicate that, during the 21st century, the global surface temperature is likely to rise a further 0.3 to 1.7 °C (0.5 to 3.1 °F) in a moderate scenario, or as much as 2.6 to 4.8 °C (4.7 to 8.6 °F) in an extreme scenario, depending on the rate of future greenhouse gas emissions and on climate feedback effects.[125]Four possible future concentration pathways, including CO
2 and other gases’ CO
2-equivalents

subset of climate models add societal factors to a simple physical climate model. These models simulate how population, economic growth, and energy use affect – and interact with – the physical climate. With this information, these models can produce scenarios of how greenhouse gas emissions may vary in the future. This output is then used as input for physical climate models to generate climate change projections.[126] In some scenarios emissions continue to rise over the century, while others have reduced emissions.[127] Fossil fuel resources are too abundant for shortages to be relied on to limit carbon emissions in the 21st century.[128] Emissions scenarios can be combined with modelling of the carbon cycle to predict how atmospheric concentrations of greenhouse gases might change in the future.[129] According to these combined models, by 2100 the atmospheric concentration of CO2 could be as low as 380 or as high as 1400 ppm, depending on the socioeconomic scenario and the mitigation scenario.[130]

The remaining carbon emissions budget is determined by modelling the carbon cycle and the climate sensitivity to greenhouse gases.[131] According to the IPCC, global warming can be kept below 1.5 °C (2.7 °F) with a two-thirds chance if emissions after 2018 do not exceed 420 or 570 gigatonnes of CO
2, depending on exactly how the global temperature is defined. This amount corresponds to 10 to 13 years of current emissions. There are high uncertainties about the budget; for instance, it may be 100 gigatonnes of CO
2 smaller due to methane release from permafrost and wetlands.[132]

Impacts

Main article: Effects of climate change

Physical environment

Main article: Physical impacts of climate changeHistorical sea level reconstruction and projections up to 2100 published in 2017 by the U.S. Global Change Research Program[133]

The environmental effects of climate change are broad and far-reaching, affecting oceans, ice, and weather. Changes may occur gradually or rapidly. Evidence for these effects comes from studying climate change in the past, from modelling, and from modern observations.[134] Since the 1950s, droughts and heat waves have appeared simultaneously with increasing frequency.[135] Extremely wet or dry events within the monsoon period have increased in India and East Asia.[136] The rainfall rate and intensity of hurricanes and typhoons is likely increasing.[8] Frequency of tropical cyclones has not increased as a result of climate change.[137] While tornado and severe thunderstorm frequency has not increased as a result of climate change, the areas affected by such phenomena may be changing. [138]

Global sea level is rising as a consequence of glacial melt, melt of the ice sheets in Greenland and Antarctica, and thermal expansion. Between 1993 and 2017, the rise increased over time, averaging 3.1 ± 0.3 mm per year.[139] Over the 21st century, the IPCC projects that in a very high emissions scenario the sea level could rise by 61–110 cm.[140] Increased ocean warmth is undermining and threatening to unplug Antarctic glacier outlets, risking a large melt of the ice sheet[141] and the possibility of a 2-meter sea level rise by 2100 under high emissions.[142]

Climate change has led to decades of shrinking and thinning of the Arctic sea ice, making it vulnerable to atmospheric anomalies.[143] While ice-free summers are expected to be rare at 1.5 °C (2.7 °F) degrees of warming, they are set to occur once every three to ten years at a warming level of 2.0 °C (3.6 °F).[144] Higher atmospheric CO
2 concentrations have led to changes in ocean chemistry. An increase in dissolved CO
2 is causing oceans to acidify.[145] In addition, oxygen levels are decreasing as oxygen is less soluble in warmer water,[146] with hypoxic dead zones expanding as a result of algal blooms stimulated by higher temperatures, higher CO
2 levels, ocean deoxygenation, and eutrophication.[147]

Tipping points and long-term impacts

The greater the amount of global warming, the greater the risk of passing through ‘tipping points’, thresholds beyond which certain impacts can no longer be avoided even if temperatures are reduced.[148] An example is the collapse of West Antarctic and Greenland ice sheets, where a temperature rise of 1.5 to 2.0 °C (2.7 to 3.6 °F) may commit the ice sheets to melt, although the time scale of melt is uncertain and depends on future warming.[149][15] Some large-scale changes could occur over a short time period, such as a collapse of the Atlantic Meridional Overturning Circulation,[150] which would trigger major climate changes in the North Atlantic, Europe, and North America.[151]

The long-term effects of climate change include further ice melt, ocean warming, sea level rise, and ocean acidification. On the timescale of centuries to millennia, the magnitude of climate change will be determined primarily by anthropogenic CO
2 emissions.[152] This is due to CO
2’s long atmospheric lifetime.[152] Oceanic CO
2 uptake is slow enough that ocean acidification will continue for hundreds to thousands of years.[153] These emissions are estimated to have prolonged the current interglacial period by at least 100,000 years.[154] Sea level rise will continue over many centuries, with an estimated rise of 2.3 metres per degree Celsius (4.2 ft/°F) after 2000 years.[155]

Nature and wildlife

Main article: Climate change and ecosystems

Recent warming has driven many terrestrial and freshwater species poleward and towards higher altitudes.[156] Higher atmospheric CO
2 levels and an extended growing season have resulted in global greening, whereas heatwaves and drought have reduced ecosystem productivity in some regions. The future balance of these opposing effects is unclear.[157] Climate change has contributed to the expansion of drier climate zones, such as the expansion of deserts in the subtropics.[158] The size and speed of global warming is making abrupt changes in ecosystems more likely.[159] Overall, it is expected that climate change will result in the extinction of many species.[160]

The oceans have heated more slowly than the land, but plants and animals in the ocean have migrated towards the colder poles faster than species on land.[161] Just as on land, heat waves in the ocean occur more frequently due to climate change, with harmful effects found on a wide range of organisms such as corals, kelp, and seabirds.[162] Ocean acidification is impacting organisms who produce shells and skeletons, such as mussels and barnacles, and coral reefs; coral reefs have seen extensive bleaching after heat waves.[163] Harmful algae bloom enhanced by climate change and eutrophication cause anoxia, disruption of food webs and massive large-scale mortality of marine life.[164] Coastal ecosystems are under particular stress, with almost half of wetlands having disappeared as a consequence of climate change and other human impacts.[165]

Ecological collapse. Bleaching has damaged the Great Barrier Reef and threatens reefs worldwide.[166] Extreme weather. Drought and high temperatures worsened the 2020 bushfires in Australia.[167] Arctic warmingPermafrost thaws undermine infrastructure and release methane, a greenhouse gas.[106] Habitat destruction. Many arctic animals rely on sea ice, which has been disappearing in a warming Arctic.[168] Pest propagation. Mild winters allow more pine beetles to survive to kill large swaths of forest.[169]

Humans

Main article: Effects of climate change on humansFurther information: Effects of climate change on human healthClimate securityEconomics of climate change, and Climate change and agriculture

The effects of climate change on humans, mostly due to warming and shifts in precipitation, have been detected worldwide. Regional impacts of climate change are now observable on all continents and across ocean regions,[170] with low-latitude, less developed areas facing the greatest risk.[171] Continued emission of greenhouse gases will lead to further warming and long-lasting changes in the climate system, with potentially “severe, pervasive and irreversible impacts” for both people and ecosystems.[172] Climate change risks are unevenly distributed, but are generally greater for disadvantaged people in developing and developed countries.[173]

Food and health

Health impacts include both the direct effects of extreme weather, leading to injury and loss of life,[174] as well as indirect effects, such as undernutrition brought on by crop failures.[175] Various infectious diseases are more easily transmitted in a warmer climate, such as dengue fever, which affects children most severely, and malaria.[176] Young children are the most vulnerable to food shortages, and together with older people, to extreme heat.[177] The World Health Organization (WHO) has estimated that between 2030 and 2050, climate change is expected to cause approximately 250,000 additional deaths per year from heat exposure in elderly people, increases in diarrheal disease, malaria, dengue, coastal flooding, and childhood undernutrition.[178] Over 500,000 additional adult deaths are projected yearly by 2050 due to reductions in food availability and quality.[179] Other major health risks associated with climate change include air and water quality.[180] The WHO has classified human impacts from climate change as the greatest threat to global health in the 21st century.[181]

Climate change is affecting food security and has caused reduction in global mean yields of maize, wheat, and soybeans between 1981 and 2010.[182] Future warming could further reduce global yields of major crops.[183] Crop production will probably be negatively affected in low-latitude countries, while effects at northern latitudes may be positive or negative.[184] Up to an additional 183 million people worldwide, particularly those with lower incomes, are at risk of hunger as a consequence of these impacts.[185] The effects of warming on the oceans impact fish stocks, with a global decline in the maximum catch potential. Only polar stocks are showing an increased potential.[186] Regions dependent on glacier water, regions that are already dry, and small islands are at increased risk of water stress due to climate change.[187]

Livelihoods

Economic damages due to climate change have been underestimated, and may be severe, with the probability of disastrous tail-risk events being nontrivial.[188] Climate change has likely already increased global economic inequality, and is projected to continue doing so.[189] Most of the severe impacts are expected in sub-Saharan Africa and South-East Asia, where existing poverty is already exacerbated.[190] The World Bank estimates that climate change could drive over 120 million people into poverty by 2030.[191] Current inequalities between men and women, between rich and poor, and between different ethnicities have been observed to worsen as a consequence of climate variability and climate change.[192] An expert elicitation concluded that the role of climate change in armed conflict has been small compared to factors such as socio-economic inequality and state capabilities, but that future warming will bring increasing risks.[193]

Low-lying islands and coastal communities are threatened through hazards posed by sea level rise, such as flooding and permanent submergence.[194] This could lead to statelessness for populations in island nations, such as the Maldives and Tuvalu.[195] In some regions, rise in temperature and humidity may be too severe for humans to adapt to.[196] With worst-case climate change, models project that almost one-third of humanity might live in extremely hot and uninhabitable climates, similar to the current climate found mainly in the Sahara.[197] These factors, plus weather extremes, can drive environmental migration, both within and between countries.[198] Displacement of people is expected to increase as a consequence of more frequent extreme weather, sea level rise, and conflict arising from increased competition over natural resources. Climate change may also increase vulnerabilities, leading to “trapped populations” in some areas who are not able to move due to a lack of resources.[199]

Environmental migration. Sparser rainfall leads to desertification that harms agriculture and can displace populations. Shown: Telly, Mali.[200] Agricultural changes. Droughts, rising temperatures, and extreme weather negatively impact agriculture. Shown: Texas, US.[201] Tidal flooding. Sea-level rise increases flooding in low-lying coastal regions. Shown: Venice, Italy.[202] Storm intensification. Bangladesh after Cyclone Sidr is an example of catastrophic flooding from increased rainfall.[203] Heat wave intensification. Events like the June 2019 European heat wave are becoming more common.[204]

The effects of climate change on humans are far reaching and include effects on health, environment, displacement and migration, security, society, human settlement, energy, and transport. Climate change has brought about possibly irreversible alterations to Earth’s geological, biological, and ecological systems.[1] These changes have led to the emergence of large-scale environmental hazards to human health; such as extreme weather,[2] ozone depletion, increased danger of wildfires,[3] loss of biodiversity,[4] stresses to food-producing systems, and the global spread of infectious diseases.[5] In addition, climatic changes were estimated to cause over 150,000 deaths annually in 2002, with the World Health Organization estimating this number will increase to 250,000 deaths annually between 2030 and 2050.[6][7]Flooding in the Midwestern United States, June 2008

A growing body of research explores the many impacts of climate change on human health, food supply, economic growthmigration, security, societal change, and public goods, such as drinking water. The consequences of these changes are most likely detrimental in the long term. For example, Bangladesh has experienced an increase in climate-sensitive diseases; such as malariadengue fever, childhood diarrhea, and pneumonia, among vulnerable communities.[8] Numerous studies suggest that the net current and future impacts of climate change on human society will continue being overwhelmingly negative.[9][10]

Most adverse effects of climate change are experienced by poor and low-income communities around the world, who have much higher levels of vulnerability to environmental determinants of healthwealth and other factors. They also have much lower levels of capacity available for coping with environmental change. A report on the global human impact of climate change published by the Global Humanitarian Forum in 2009, estimated more than 300,000 deaths and about $125 billion in economic losses each year. This indicates how most climate change induced mortality is due to worsening floods and droughts in developing countries.

Key vulnerabilities

Most of the key vulnerabilities to climate change are related to climate phenomena that exceed thresholds for adaptation; such as extreme weather events or abrupt climate change, as well as limited access to resources (financial, technical, human, institutional) to cope. In 2007, the IPCC published a report of key vulnerabilities of industry, settlements, and society to climate change.[11] This assessment included a level of confidence for each key vulnerability:

  • Very high confidence: Interactions between climate change and urbanization: this is most notable in developing countries, where urbanization is often focused in vulnerable coastal areas.
  • High confidence:
    • Interactions between climate change and global economic growth: Stresses due to climate change are not only linked to the impacts of climate change, but also to the impacts of climate change policies. For example, these policies might affect development paths by requiring high cost fuel choices.
    • Fixed physical infrastructures that are important in meeting human needs: These include infrastructures that are susceptible to damage from extreme weather events or sea level rise, and infrastructures that are already close to being inadequate.
  • Medium confidence: Interactions with governmental and social cultural structures that already face other pressures (e.g., limited economic resources).

It has been estimated in the year 2020 that for every degree of temperature rise there will be 1 billion people that will live in areas with temperatures considered as too high for a normal life.[12] Humans generally live in areas where the average temperature is between 6 °C and 28 °C, with the majority of life in regions with a temperature of 11 °C – 15 °C. A temperature of 29 degrees or higher is considered as too hot for normal life and currently found only in 0.8% of the land surface (mainly in Sahara desert). However, according to the study by the year 2070 in the RCP8.5 (business as usual) scenario, 30% of human population will live in this area.[13][12] In the supplementary materials of the study, it is said that according to this scenario the global average temperature will be 3.2 degree higher in the year 2070 relatively to the pre – industrial baseline.[14] According to the United Nations Environmental Program report, the temperature will rise by 3.2 degrees by the end of the century. Even if all the pledges in Paris Agreement (as they were in 2019) will be accomplished.[15]

Health

Main article: Effects of climate change on human healthClimate Crisis = Health Crisis

Climate change poses a wide range of risks to population health. If global climate change continues on its current trajectory, these risks will increase in future decades to potentially critical levels.[16] The three main categories of health risks include: (i) direct-acting effects (e.g. due to heat waves, amplified air pollution, and physical weather disasters), (ii) impacts mediated via climate-related changes in ecological systems and relationships (e.g. crop yields, mosquito ecology, marine productivity), and (iii) the more diffuse (indirect) consequences relating to impoverishment, displacement, resource conflicts (e.g. water), and post-disaster mental health problems.

Climate change threatens to slow, halt or reverse international progress towards reducing child under-nutrition, deaths from diarrheal diseases and the spread of other infectious diseases. Climate change acts predominantly by exacerbating the existing, often enormous, health problems, especially in the poorer parts of the world. Current variations in weather conditions already have many adverse impacts on the health of poor people in developing nations,[17] and these too are likely to be ‘multiplied’ by the added stresses of climate change.

A changing climate thus affects the prerequisites of population health: clean air and water, sufficient food, natural constraints on infectious disease agents, and the adequacy and security of shelter. A warmer and more variable climate leads to higher levels of some air pollutants. It increases the rates and ranges of transmission of infectious diseases through unclean water and contaminated food, and by affecting vector organisms (such as mosquitoes) and intermediate or reservoir host species that harbour the infectious agent (such as cattle,[18] bats and rodents). Changes in temperature, rainfall and seasonality compromise agricultural production in many regions, including some of the least developed countries, thus jeopardising child health and growth and the overall health and functional capacity of adults. As warming proceeds, the severity (and perhaps frequency) of weather-related disasters will increase – and appears to have done so in a number of regions of the world over the past several decades.[19]

Health equity and climate change have a major impact on human health and quality of life, and are interlinked in a number of ways. The report of the WHO Commission on Social Determinants of Health points out that disadvantaged communities are likely to shoulder a disproportionate share of the burden of climate change because of their increased exposure and vulnerability to health threats. Over 90 percent of malaria and diarrhea deaths are borne by children aged 5 years or younger, mostly in developing countries.[20] Other severely affected population groups include women, the elderly and people living in small island developing states and other coastal regions, mega-cities or mountainous areas.[21]

Psychological impacts

The USNS Comfort on its way to deliver relief after Hurricane Katrina. Rapid assistance and restoration of security for those affected by extreme weather reduces the risk of long term psychological impact.This section is an excerpt from Psychological impact of climate change[edit]

Climate change causes a number of psychological effects on the earth’s inhabitants. These include emotional states such as eco-anxiety, eco-grief and eco-anger. While unpleasant, such emotions are often not harmful, and can be rational responses to the degradation of the natural world, motivating adaptive action. Other effects, such as Post-traumatic stress (PTS), can be more dangerous. In the 21st century, academics, medical professionals and various other actors are seeking to understand these impacts, in order to assist in their relief, make more accurate predictions, and to assist efforts to mitigate and adapt to global warming.There are three broad channels by which climate change affects people’s mental state: directly, indirectly or via awareness. The direct channel includes stress related conditions being caused by exposure to extreme weather events. The indirect pathway can be via disruption to economic and social activities, such as when an area of farmland is less able to produce food. And the third channel can be of mere awareness of the climate change threat, even by individuals who are not otherwise affected by it. There are many exceptions, but generally it is people in developing countries who are more exposed to the direct impact and economic disruption caused by climate changes. Whereas recently identified climate related psychological conditions like eco-anxiety, which can result just from awareness of the threat, tend to affect people across the planet.

Infectious diseases

This section is an excerpt from Climate change and infectious diseases[edit]Global climate change has resulted a wide range of impacts on the spread of infectious diseases. Like other climate change impacts on human health, climate change exacerbates existing inequalities and challenges in managing infectious disease. It also increases the likelihood of certain kinds of new infectious disease challenges. Infectious diseases whose transmission can be impacted by climate change include dengue fevermalariatick-borne diseaseleishmaniasisebola. There is no direct evidence that the spread of COVID-19 is worsened or is caused by climate change, although investigations continue.

Environment

Climate change may dramatically impact habitat loss, for example, arid conditions may cause the deforestation of rainforests, as has occurred in the past.[22]

Temperature changes

A sustained wet-bulb temperature exceeding 35 °C is a threshold at which the resilience of human systems is no longer able to adequately cool the skin. A study by NOAA from 2013 concluded that heat stress will reduce labor capacity considerably under current emissions scenarios.[23] One study found that limiting warming to 1.5 degrees is necessary for avoiding from large and densely populated territories in tropical regions to pass the threshold of 35 °C of wet bulb temperature[24] There is evidence to show that high temperatures can increase mortality rates among fetuses and children.[25] Although the main focus is often on the health impacts and risks of higher temperatures, it should be remembered that they also reduce learning and worker productivity, which can impact a country’s economy and development.

Low temperature

Climate change contributes to cold snaps due to disruptions in the polar vortex caused by a decline in Arctic sea ice.[26] This causes frigid, cold air to spill from the Arctic and into areas of the northern hemisphere that usually don’t experience such cold temperatures, such as the North American southeast, midwest, northeast, and parts of Europe.[26] This is a predicted short-term effect of climate change in the winter. This brings along extreme cold temperatures for a short period of time, and results in large scale disruption to human life. A statistic from data on the winter season of 2013-14 found that of the most notable of the winter storms – most of which were caused by the disruption of the polar vortex – caused $263 million in damage, 32 fatalities, and 9 injuries.[27] Furthermore, infrastructure damage in the form of closed roads, schools, airports, and other civil functions occurred throughout the northeast, and in some parts of the Midwestern and Southeastern United States. A commercial airliner skidded off the runway and into a nearby snowbank at John F. Kennedy International Airport in New York during the 2014 cold snap.[27] The winter season of 2013-2014 also caused some crop damage as shown in Ohio losing 97% of their grape harvest.[28] Further harvests in the following years were also affected as freeze damage reached deep into the trunks of some plants killing off the plant. The total damages extended to roughly $4 million, impacting Ohio’s economy and wine production. Cold events are expected to increase in the short term while in the long term the increasing global temperature is going to give way to more heat-related events.

Water

See also: Water crisisBaseline water stress per region: the ratio of total annual water withdrawals to total available annual renewable supply, accounting for upstream consumptive use

The freshwater resources that humans rely on are highly sensitive to variations in weather and climate. The sustained alteration of climate directly impacts the hydrosphere and hydrologic cycle changing how humans interact with water across the globe In 2007, the IPCC reported with high confidence that climate change has a net negative impact on water resources and freshwater ecosystems in all regions.[29] The IPCC also found with very high confidence that arid and semi-arid areas are particularly exposed to freshwater impacts.[29] In addition, the IPCC forecasts increased uncertainty in the amount and frequency of precipitation from the year 2000 to 2100.[30]

As the climate warms, it changes the nature of global rainfall, evaporation, snow, stream flow and other factors that affect water supply and quality. Specific impacts include:

  • Warmer water temperatures affect water quality and accelerate water pollution.[31]
  • Sea level rise is projected to increase salt-water intrusion into groundwater in some regions. This reduces the amount of freshwater available for drinking and farming.[31][32]
  • In some areas, shrinking glaciers and snow deposits threaten the water supply.[33] Areas that depend on melted water runoff will likely see that runoff depleted, with less flow in the late summer and spring peaks occurring earlier.[31] This can affect the ability to irrigate crops. (This situation is particularly acute for irrigation in South America,[34] for irrigation and drinking supplies in Central Asia, and for hydropower in Norway, the Alps, and the Pacific Northwest of North America.)
  • Increased extreme weather means more water falls on hardened ground unable to absorb it, leading to flash floods instead of a replenishment of soil moisture or groundwater levels.[35]
  • Increased evaporation will reduce the effectiveness of reservoirs.
  • At the same time, human demand for water will grow for the purposes of cooling and hydration.
  • Increased precipitation can lead to changes in water-borne and vector-borne diseases.[36]

Changes in freshwater availability extend to groundwater as well and human activities in conjunction with climate change interfere with groundwater recharge patterns. One of the leading anthropogenic activities resulting in the depletion of groundwater includes irrigation. Roughly 40% of global irrigation is supported by groundwater and irrigation is the primary activity resulting in groundwater storage loss across the U.S.[37] Furthermore, in the US an estimated 800 km^3 of groundwater was depleted in the past century.[37] The development of cities and other areas of highly concentrated water usage has created a strain on groundwater resources. Surface water and groundwater interactions experience reduced “interflow” between the surface and subsurface in post- development scenarios leading to depleted water tables.[38] Groundwater recharge rates are also affected by rising temperatures which increase surface evaporation and transpiration resulting in decreased soil water content.[39] These anthropogenic changes to groundwater storage, such as over pumping and the depletion of water tables combined with climate change, effectively reshape the hydrosphere and impact the ecosystems that depend on the groundwater.[40]

Drowning

Researchers found that there is a strong correlation between higher temperatures and drowning accidents in large lakes, and that’s because the ice gets thinner and weaker. In fact Canadian studies show that since 1990, around 4000 cases of drowning were detected. Study leader Sapna Sharma, from York University in Toronto, Canada conformed that “We can confidently say that there is a quite a strong correlation between warmer winter air temperatures and more winter drownings”.[41] Even though not all drowning accidents lead to death, drowning itself could be a very harmful experience, especially since most victims are children or young adults. Due to very cold water, children suffer from cardiac arrest and later from neurological damages.

In addition, the fear of drowning affects the lifestyle of indigenous people, who rely on icy lakes to hunt, fish and travel.

Although authorities are spreading awareness about the danger of drowning, prohibiting snowmobiles on lakes, and limiting access until ice is safe, researchers predict that the cases will still increase, especially during the lockdown, because people are spending more time outdoor.

Lack of oxygen

The possibility has been discussed of a massive mortality of humans due to lack of oxygen in case of a temperature rise of 6 degrees above preindustrial levels. This is because such conditions can harm phytoplankton which produces a large part of the oxygen on Earth.[42][43]

Displacement and migration

See also: Environmental migrantA refugee camp north of Goma near the Rwandan border

Climate change causes displacement of people in several ways, the most obvious—and dramatic—being through the increased number and severity of weather-related disasters which destroy homes and habitats causing people to seek shelter or livelihoods elsewhere. Effects of climate change such as desertification and rising sea levels gradually erode livelihood and force communities to abandon traditional homelands for more accommodating environments. This is currently happening in areas of Africa’s Sahel, the semi-arid belt that spans the continent just below its northern deserts. Deteriorating environments triggered by climate change can also lead to increased conflict over resources which in turn can displace people.[44]

The IPCC has estimated that 150 million environmental migrants will exist by the year 2050, due mainly to the effects of coastal flooding, shoreline erosion and agricultural disruption.[45] However, the IPCC also cautions that it is extremely difficult to measure the extent of environmental migration due to the complexity of the issue and a lack of data.[11]

According to the Internal Displacement Monitoring Centre, more than 42 million people were displaced in Asia and the Pacific during 2010 and 2011, more than twice the population of Sri Lanka. This figure includes those displaced by storms, floods, and heat and cold waves. Still others were displaced by drought and sea-level rise. Most of those compelled to leave their homes eventually returned when conditions improved, but an undetermined number became migrants, usually within their country, but also across national borders.[46] The same organization issued a report in 2021, saying that in 2020 approximately 30 million people were displaced by extreme weather events while approximately 10 million by violence and wars and climate change significantly contributed to this.[47][48]

Asia and the Pacific is the global area most prone to natural disasters, both in terms of the absolute number of disasters and of populations affected. It is highly exposed to climate impacts, and is home to highly vulnerable population groups, who are disproportionately poor and marginalized. A recent Asian Development Bank report highlights “environmental hot spots” that are particular risk of flooding, cyclonestyphoons, and water stress.[49]

Some Pacific Ocean island nations, such as TuvaluKiribati, and the Maldives,[50] are considering the eventual possibility of evacuation, as flood defense may become economically unrealistic. Tuvalu already has an ad hoc agreement with New Zealand to allow phased relocation.[51] However, for some islanders relocation is not an option. They are not willing to leave their homes, land and families. Some simply don’t know the threat that climate change has on their island and this is mainly down to the lack of awareness that climate change even exists. In Vutia on Viti Levu, Fiji’s main island, half the respondents to a survey had not heard of climate change (Lata and Nuun 2012). Even where there is awareness many believe that it is a problem caused by developed countries and should therefore be solved by developed countries.[52] As of 2020 many Pacific islands are growing in size, contradicting earlier claims.[53]

Governments have considered various approaches to reduce migration compelled by environmental conditions in at-risk communities, including programs of social protection, livelihoods development, basic urban infrastructure development, and disaster risk management. Some experts even support migration as an appropriate way for people to cope with environmental changes. However, this is controversial because migrants – particularly low-skilled ones – are among the most vulnerable people in society and are often denied basic protections and access to services.[49]

Climate change is only one factor that may contribute to a household’s decision to migrate; other factors may include povertypopulation growth or employment options.[54] For this reason, it is difficult to classify environmental migrants as actual “refugees” as legally defined by the UNHCR.[55] Neither the UN Framework Convention on Climate Change nor its Kyoto Protocol, an international agreement on climate change, includes any provisions concerning specific assistance or protection for those who will be directly affected by climate change.[56]

In small islands and megadeltasinundation as a result of sea level rise is expected to threaten vital infrastructure and human settlements.[57][58] This could lead to issues of statelessness for populations in countries such as the Maldives and Tuvalu[59] and homelessness in countries with low-lying areas such as Bangladesh.

The World Bank predicts that a “severe hit” will spur conflict and migration across the Middle EastCentral Asia, and Africa.[60]