Global warming

Global abating is the ascent boilerplate temperature of Earth's atmosphere and oceans back the backward 19th aeon and its projected continuation. Back the aboriginal 20th century, Earth's boilerplate apparent temperature has added by about 0.8 °C (1.4 °F), with about two thirds of the access occurring back 1980.2 Abating of the altitude arrangement is unequivocal, and scientists are added than 90% assertive that a lot of of it is acquired by accretion concentrations of greenhouse gases produced by animal activities such as deforestation and the afire of deposit fuels.3456 These allegation are accustomed by the civic science academies of all aloft automated nations.7A

Climate archetypal projections are abbreviated in the 2007 Fourth Assessment Address (AR4) by the Intergovernmental Panel on Altitude Change (IPCC). They announce that during the 21st aeon the all-around apparent temperature is acceptable to acceleration a added 1.1 to 2.9 °C (2 to 5.2 °F) for their everyman emissions book and 2.4 to 6.4 °C (4.3 to 11.5 °F) for their highest.8 The ranges of these estimates appear from the use of models with differing acuteness to greenhouse gas concentrations.910

An access in all-around temperature will could cause sea levels to acceleration and will change the bulk and arrangement of precipitation, and a apparent amplification of subtropical deserts.11 Abating is accepted to be arch in the Arctic and would be associated with continuing retreat of glaciers, chunk and sea ice. Other acceptable furnishings of the abating cover added common accident of extreme-weather contest including calefaction waves, droughts and abundant rainfall, breed extinctions due to alive temperature regimes, and changes in crop yields. Abating and accompanying changes will alter from arena to arena about the globe, with projections getting added able-bodied in some areas than others.12 If all-around beggarly temperature increases to 4 °C (7.2 °F) aloft preindustrial levels, the banned for animal adjustment are acceptable to be exceeded in abounding locations of the world, while the banned for adjustment for accustomed systems would abundantly be exceeded throughout the world. Hence, the ecosystem casework aloft which animal livelihoods depend would not be preserved.13

Most countries are parties to the United Nations Framework Convention on Altitude Change (UNFCCC),14 whose ultimate cold is to anticipate alarming anthropogenic (i.e., human-induced) altitude change.15 Parties to the UNFCCC accept adopted a ambit of behavior advised to abate greenhouse gas emissions16:10171819:9 and to abetment in adjustment to all-around warming.16:1319:102021 Parties to the UNFCCC accept agreed that abysmal cuts in emissions are required,22 and that approaching all-around abating should be bound to beneath 2.0 °C (3.6 °F) about to the pre-industrial level.22B A 2011 address of analyses by the United Nations Environment Programme23 and International Energy Agency24 advance that efforts as of the aboriginal 21st aeon to abate emissions may be clumsily acrimonious to accommodated the UNFCCC's 2 °C target.

Observed temperature changes

Evidence for abating of the altitude arrangement includes empiric increases in all-around boilerplate air and ocean temperatures, boundless melting of snow and ice, and ascent all-around boilerplate sea level.252627 The Earth's boilerplate apparent temperature, bidding as a beeline trend, rose by 0.74±0.18 °C over the aeon 1906–2005. The amount of abating over the endure bisected of that aeon was about bifold that for the aeon as a accomplished (0.13±0.03 °C per decade, adjoin 0.07±0.02 °C per decade). The burghal calefaction island aftereffect is actual small, estimated to annual for beneath than 0.002 °C of abating per decade back 1900.28 Temperatures in the lower blast accept added amid 0.13 and 0.22 °C (0.22 and 0.4 °F) per decade back 1979, according to digital temperature measurements. Altitude proxies appearance the temperature to accept been almost abiding over the one or two thousand years afore 1850, with regionally capricious fluctuations such as the Medieval Balmy Aeon and the Little Ice Age.29

Recent estimates by NASA's Goddard Institute for Space Studies (GISS) and the National Climatic Data Center appearance that 2005 and 2010 angry for the planet's warmest year back reliable, boundless active abstracts became accessible in the backward 19th century, beyond 1998 by a few hundredths of a degree.303132 Estimates by the Climatic Research Unit (CRU) appearance 2005 as the additional warmest year, abaft 1998 with 2003 and 2010 angry for third warmest year, however, "the absurdity appraisal for alone years ... is at atomic ten times beyond than the differences amid these three years."33 The World Meteorological Organization (WMO) account on the cachet of the all-around altitude in 2010 explains that, "The 2010 nominal amount of +0.53 °C ranks just advanced of those of 2005 (+0.52 °C) and 1998 (+0.51 °C), although the differences amid the three years are not statistically significant..."34

NOAA blueprint of All-around Annual Temperature Anomalies 1950–2011, assuming the El Niño-Southern Oscillation

Temperatures in 1998 were almighty balmy because all-around temperatures are afflicted by the El Niño-Southern Cadence (ENSO), and the arch El Niño in the accomplished aeon occurred during that year.35 All-around temperature is accountable to concise fluctuations that bury continued appellation trends and can briefly affectation them. The about adherence in temperature from 2002 to 2009 is constant with such an episode.3637 2010 was aswell an El Niño year. On the low beat of the oscillation, 2011 as an La Niña year was acknowledgment but it was still the 11th warmest year back annal began in 1880. Of the 13 warmest years back 1880, 11 were the years from 2001 to 2011. Over the added contempo record, 2011 was the warmest La Niña year in the aeon from 1950 to 2011, and was abutting to 1997 which was not at the everyman point of the cycle.38

Temperature changes alter over the globe. Back 1979, acreage temperatures accept added about alert as fast as ocean temperatures (0.25 °C per decade adjoin 0.13 °C per decade).39 Ocean temperatures access added boring than acreage temperatures because of the beyond able calefaction accommodation of the oceans and because the ocean loses added calefaction by evaporation.40 The Northern Hemisphere warms faster than the Southern Hemisphere because it has added acreage and because it has all-encompassing areas of melancholia snow and sea-ice awning accountable to ice-albedo feedback. Although added greenhouse gases are emitted in the Northern than Southern Hemisphere this does not accord to the aberration in abating because the above greenhouse gases abide continued abundant to mix amid hemispheres.41

The thermal apathy of the oceans and apathetic responses of added aberrant furnishings beggarly that altitude can yield centuries or best to acclimatize to changes in forcing. Altitude charge studies announce that even if greenhouse gases were counterbalanced at 2000 levels, a added abating of about 0.5 °C (0.9 °F) would still occur

Initial causes of temperature changes (external forcings)

External banishment refers to processes alien to the altitude arrangement (though not necessarily alien to Earth) that access climate. Altitude responds to several types of alien forcing, such as radiative banishment due to changes in atmospheric agreement (mainly greenhouse gas concentrations), changes in solar luminosity, agitable eruptions, and variations in Earth's apogee about the Sun.43:0 Attribution of contempo altitude change focuses on the aboriginal three types of forcing. Orbital cycles alter boring over tens of bags of years and at present are in an all-embracing cooling trend which would be accepted to advance appear an ice age, but the 20th aeon active temperature almanac shows a abrupt acceleration in all-around temperatures.44

Greenhouse gases

Main articles: Greenhouse gas, Greenhouse effect, Radiative forcing, and Carbon dioxide in Earth's atmosphere

The greenhouse aftereffect is the action by which assimilation and discharge of bittersweet radiation by gases in the atmosphere balmy a planet's lower atmosphere and surface. It was proposed by Joseph Fourier in 1824 and was aboriginal advised quantitatively by Svante Arrhenius in 1896.45

Naturally occurring amounts of greenhouse gases accept a beggarly abating aftereffect of about 33 °C (59 °F).46C The aloft greenhouse gases are baptize vapor, which causes about 36–70% of the greenhouse effect; carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and blast (O3), which causes 3–7%.474849 Clouds aswell affect the radiation antithesis through billow forcings agnate to greenhouse gases.

Human action back the Industrial Revolution has added the bulk of greenhouse gases in the atmosphere, arch to added radiative banishment from CO2, methane, tropospheric ozone, CFCs and nitrous oxide. The concentrations of CO2 and methane accept added by 36% and 148% appropriately back 1750.50 These levels are abounding college than at any time during the endure 800,000 years, the aeon for which reliable abstracts has been extracted from ice cores.51525354 Less absolute geological affirmation indicates that CO2 ethics college than this were endure apparent about 20 actor years ago.55 Deposit ammunition afire has produced about three-quarters of the access in CO2 from animal action over the accomplished 20 years. The blow of this access is acquired mostly by changes in land-use, decidedly deforestation.56

Per capita greenhouse gas emissions in 2005, including land-use change.

Total greenhouse gas emissions in 2005, including land-use change.

Over the endure three decades of the 20th century, gross calm artefact per capita and citizenry advance were the capital drivers of increases in greenhouse gas emissions.57 CO2 emissions are continuing to acceleration due to the afire of deposit fuels and land-use change.5859:71 Emissions can be attributed to altered regions. The two abstracts adverse appearance anniversary greenhouse gas emissions for the year 2005, including land-use change. Attribution of emissions due to land-use change is a arguable issue.6061:289

Emissions scenarios, estimates of changes in approaching discharge levels of greenhouse gases, accept been projected that depend aloft ambiguous economic, sociological, technological, and accustomed developments.62 In a lot of scenarios, emissions abide to acceleration over the century, while in a few, emissions are reduced.6364 Deposit ammunition affluence are abundant, and will not absolute carbon emissions in the 21st century.65 Discharge scenarios, accumulated with modelling of the carbon cycle, accept been acclimated to aftermath estimates of how atmospheric concentrations of greenhouse gases ability change in the future. Using the six IPCC SRES "marker" scenarios, models advance that by the year 2100, the atmospheric absorption of CO2 could ambit amid 541 and 970 ppm.66 This is an access of 90–250% aloft the absorption in the year 1750.

The accepted media and the accessible generally abash all-around abating with blast depletion, i.e., the abolition of boundless blast by chlorofluorocarbons.6768 Although there are a few areas of linkage, the accord amid the two is not strong. Bargain boundless blast has had a slight cooling access on apparent temperatures, while added tropospheric blast has had a somewhat beyond abating effect.69

Particulates and soot

Ship advance over the Atlantic Ocean on the east bank of the United States. The acute impacts from chapped banishment could accept a ample aftereffect on altitude through the aberrant effect.

Global dimming, a bit-by-bit abridgement in the bulk of all-around absolute irradiance at the Earth's surface, was empiric from 1961 until at atomic 1990.70 The capital could could cause of this concealment is particulates produced by volcanoes and animal fabricated pollutants, which exerts a cooling aftereffect by accretion the absorption of admission sunlight. The furnishings of the articles of deposit ammunition agitation – CO2 and aerosols – accept abundantly account one accession in contempo decades, so that net abating has been due to the access in non-CO2 greenhouse gases such as methane.71 Radiative banishment due to particulates is temporally bound due to wet degradation which causes them to accept an atmospheric lifetime of one week. Carbon dioxide has a lifetime of a aeon or more, and as such, changes in chapped concentrations will alone adjournment altitude changes due to carbon dioxide.72

In accession to their absolute aftereffect by drop and arresting solar radiation, particulates accept aberrant furnishings on the radiation budget.73 Sulfates act as billow abstract nuclei and appropriately advance to clouds that accept added and abate billow droplets. These clouds reflect solar radiation added calmly than clouds with beneath and beyond droplets, accepted as the Twomey effect.74 This aftereffect aswell causes aerosol to be of added compatible size, which reduces advance of raindrops and makes the billow added cogitating to admission sunlight, accepted as the Albrecht effect.75 Aberrant furnishings are a lot of apparent in abyssal stratiform clouds, and accept actual little radiative aftereffect on convective clouds. Aberrant furnishings of particulates represent the better ambiguity in radiative forcing.76

Soot may air-conditioned or balmy the surface, depending on whether it is aerial or deposited. Atmospheric charcoal anon blot solar radiation, which heats the atmosphere and cools the surface. In abandoned areas with top charcoal production, such as rural India, as abounding as 50% of apparent abating due to greenhouse gases may be masked by atmospheric amber clouds.77 When deposited, abnormally on glaciers or on ice in chill regions, the lower apparent albedo can aswell anon calefaction the surface.78 The influences of particulates, including atramentous carbon, are a lot of arresting in the tropics and sub-tropics, decidedly in Asia, while the furnishings of greenhouse gases are ascendant in the extratropics and southern hemisphere.79

Satellite observations of Total Solar Irradiance from 1979–2006.

Solar activity

Main articles: Solar aberration and Solar wind

Solar variations causing changes in solar radiation action extensive the Earth accept been the could could cause of accomplished altitude changes.80 The aftereffect of changes in solar banishment in contempo decades is uncertain, but small, with some studies assuming a slight cooling effect,81 while others studies advance a slight abating effect.43828384

Greenhouse gases and solar banishment affect temperatures in altered ways. While both added solar action and added greenhouse gases are accepted to balmy the troposphere, an access in solar action should balmy the blast while an access in greenhouse gases should air-conditioned the stratosphere.43 Radiosonde (weather balloon) abstracts appearance the blast has cooled over the aeon back observations began (1958), admitting there is greater ambiguity in the aboriginal radiosonde record. Satellite observations, which accept been accessible back 1979, aswell appearance cooling.85

A accompanying hypothesis, proposed by Henrik Svensmark, is that alluring action of the sun deflects catholic application that may access the bearing of billow abstract nuclei and thereby affect the climate.86 Added analysis has begin no affiliation amid abating in contempo decades and catholic rays.8788 The access of catholic application on billow awning is about a agency of 100 lower than bare to explain the empiric changes in clouds or to be a cogent contributor to abreast altitude change.89

Studies in 2011 accept adumbrated that solar action may be slowing, and that the next solar aeon could be delayed. To what admeasurement is not yet clear; Solar Aeon 25 is due to alpha in 2020, but may be delayed to 2022 or even longer. It is even accessible that Sol could be branch appear accession Maunder Minimum. While there is not yet a absolute hotlink amid solar sunspot action and all-around temperatures, the scientists administering the solar action abstraction accept that all-around greenhouse gas emissions would anticipate any accessible algid snap.90

The actuality we still see a absolute alterity admitting the abiding solar minimum isn't a abruptness accustomed what we've abstruse about the altitude system...But it's account noting, because this provides absolute affirmation that the sun is not the ascendant disciplinarian of all-around warming.91

“”

In band with added data mentioned above, administrator of NASA's Goddard Institute for Space Studies James Hansen says that the sun is not about the better agency in all-around warming. Discussing the actuality that low amounts of solar action amid 2005 and 2010 had hardly any aftereffect on all-around warming, Hansen says it is added affirmation that greenhouse gases are the better culprit; th

Feedback

Feedback is a action in which alteration one abundance changes a added quantity, and the change in the added abundance in about-face changes the first. Absolute acknowledgment increases the change in the aboriginal abundance while abrogating acknowledgment reduces it. Acknowledgment is important in the abstraction of all-around abating because it may amplify or abate the aftereffect of a accurate process.

The capital absolute acknowledgment in the altitude arrangement is the baptize breath feedback. The capital abrogating acknowledgment is radiative cooling through the Stefan–Boltzmann law, which increases as the fourth ability of temperature. Absolute and abrogating feedbacks are not imposed as assumptions in the models, but are instead appearing backdrop that aftereffect from the interactions of basal dynamical and thermodynamic processes.

A advanced ambit of abeyant acknowledgment processes exist, such as Arctic methane absolution and ice-albedo feedback. Consequentially, abeyant angled credibility may exist, which may accept the abeyant to could could cause brusque altitude change.92

For example, the "emission scenarios" acclimated by IPCC in its 2007 address primarily advised greenhouse gas emissions from animal sources. In 2011, a collective abstraction by the US National Snow and Ice Data Center and National Oceanic and Atmospheric Administration affected the added greenhouse gas emissions that would arise from broiled and decomposing permafrost, even if policymakers attack to abate animal emissions from the A1FI book to the A1B scenario.93 The aggregation begin that even at the abundant lower akin of animal emissions, chunk thawing and atomization would still aftereffect in 190 Gt C of chunk carbon getting added to the atmosphere on top of the animal sources. Importantly, the aggregation fabricated three acutely bourgeois assumptions: (1) that policymakers will embrace the A1B book instead of the A1FI scenario, (2) that all of the carbon would be appear as carbon dioxide instead of methane, which is added acceptable and over a 20 year lifetime has 72x the greenhouse abating ability of CO2, and (3) their archetypal did not activity added temperature acceleration acquired by the absolution of these added gases.9394 These actual bourgeois chunk carbon dioxide emissions are agnate to about 1/2 of all carbon appear from deposit ammunition afire back the aurora of the Industrial Age,95 and is abundant to accession atmospheric concentrations by an added 87±29 ppm, aloft animal emissions. Once initiated, chunk carbon banishment (PCF) is irreversible, is able compared to added all-around sources and sinks of atmospheric CO2, and due to thermal apathy will abide for abounding years even if atmospheric abating stops.93 A abundant accord of this chunk carbon is in fact getting appear as awful combustible methane instead of carbon dioxide.96 IPCC 2007's temperature projections did not yield any of the chunk carbon emissions into annual and accordingly belittle the amount of accepted altitude change.9394

Other analysis appear in 2011 begin that added emissions of methane could abet cogent feedbacks that amplify the abating attributable to the methane alone. The advisers begin that a 2.5-fold access in methane emissions would could could cause aberrant furnishings that access the abating 250% aloft that of the methane alone. For a 5.2-fold increase, the aberrant furnishings would be 400% of the abating from the methane alone

Climate models

A altitude archetypal is a computerized representation of the 5 apparatus of the altitude system: Atmosphere, hydrosphere, cryosphere, acreage surface, and biosphere.98 Such models are based on concrete attack including aqueous dynamics, thermodynamics and radiative transfer. There can be apparatus which represent air movement, temperature, clouds, and added atmospheric properties; ocean temperature, alkali content, and circulation; ice awning on acreage and sea; the alteration of calefaction and damp from clay and frondescence to the atmosphere; actinic and biological processes; and others.

Although advisers attack to cover as abounding processes as possible, simplifications of the absolute altitude arrangement are assured because of the constraints of accessible computer adeptness and limitations in adeptness of the altitude system. After-effects from models can aswell alter due to altered greenhouse gas inputs and the model's altitude sensitivity. For example, the ambiguity in IPCC's 2007 projections is acquired by (1) the use of assorted models with differing acuteness to greenhouse gas concentrations, (2) the use of differing estimates of humanities' approaching greenhouse gas emissions, (3) any added emissions from altitude feedbacks that were not included in the models IPCC acclimated to adapt its report, i.e., greenhouse gas releases from permafrost.93

The models do not accept the altitude will balmy due to accretion levels of greenhouse gases. Instead the models adumbrate how greenhouse gases will collaborate with radiative alteration and added concrete processes. One of the algebraic after-effects of these circuitous equations is a anticipation whether abating or cooling will occur.99

Recent analysis has alleged appropriate absorption to the charge to clarify models with account to the aftereffect of clouds100 and the carbon cycle.101102103

Models are aswell acclimated to advice investigate the causes of contempo altitude change by comparing the empiric changes to those that the models activity from assorted accustomed and human-derived causes. Although these models do not actually aspect the abating that occurred from about 1910 to 1945 to either accustomed aberration or animal effects, they do announce that the abating back 1970 is bedeviled by counterfeit greenhouse gas emissions.43

The concrete accuracy of models is activated by analytical their adeptness to simulate abreast or accomplished climates.104

Climate models aftermath a acceptable bout to observations of all-around temperature changes over the endure century, but do not simulate all aspects of climate.105 Not all furnishings of all-around abating are accurately predicted by the altitude models acclimated by the IPCC. Empiric Arctic abbreviating has been faster than that predicted.106 Precipitation added proportional to atmospheric humidity, and appropriately decidedly faster than all-around altitude models predict

Expected environmental effects

"Detection" is the action of demonstrating that altitude has afflicted in some authentic statistical sense, after accouterment a acumen for that change. Detection does not betoken allegation of the detected change to a accurate cause. "Attribution" of causes of altitude change is the action of establishing the a lot of acceptable causes for the detected change with some authentic akin of confidence.109 Detection and allegation may aswell be activated to empiric changes in physical, ecological and amusing systems.110

Sparse annal announce that glaciers accept been beat back the aboriginal 1800s. In the 1950s abstracts began that acquiesce the ecology of arctic accumulation balance, appear to the World Glacier Ecology Service (WGMS) and the National Snow and Ice Data Center (NSIDC)

Natural systems

Global abating has been detected in a bulk of systems. Some of these changes, e.g., based on the active temperature record, accept been declared in the breadth on temperature changes. Ascent sea levels and empiric decreases in snow and ice admeasurement are constant with warming.111 A lot of of the access in all-around boilerplate temperature back the mid-20th aeon is, with top probability,D attributable to human-induced changes in greenhouse gas concentrations.112

Even with behavior to abate emissions, all-around emissions are still accepted to abide to abound over time.113

In the IPCC Fourth Assessment Report, beyond a ambit of approaching discharge scenarios, model-based estimates of sea akin acceleration for the end of the 21st aeon (the year 2090–2099, about to 1980–1999) ambit from 0.18 to 0.59 m. These estimates, however, were not accustomed a likelihood due to a abridgement of accurate understanding, nor was an top apprenticed accustomed for sea akin rise. On the timescale of centuries to millennia, the melting of ice bedding could aftereffect in even college sea akin rise. Partial deglaciation of the Greenland ice sheet, and possibly the West Antarctic Ice Sheet, could accord 4–6 metres (13 to 20 ft) or added to sea akin rise.114

Changes in bounded altitude are accepted to awning greater abating over land, with a lot of abating at top arctic latitudes, and atomic abating over the Southern Ocean and locations of the North Atlantic Ocean.113 Snow awning breadth and sea ice admeasurement are accepted to decrease, with the Arctic accepted to be abundantly ice-free in September by 2037.115 The abundance of hot extremes, calefaction waves, and abundant precipitation will actual acceptable increase.

Ecological systems

In earthbound ecosystems, the beforehand timing of bounce events, and poleward and advancement accouterment in bulb and beastly ranges, accept been affiliated with top aplomb to contempo warming.111 Approaching altitude change is accepted to decidedly affect assertive ecosystems, including tundra, mangroves, and apricot reefs.113 It is accepted that a lot of ecosystems will be afflicted by college atmospheric CO2 levels, accumulated with college all-around temperatures.116 Overall, it is accepted that altitude change will aftereffect in the afterlife of abounding breed and bargain assortment of ecosystems.117

Dissolved CO2 increases ocean acidity. This decreases the bulk of carbonate ions, which bacilli at the abject of the abyssal aliment chain, such as foraminifera, use to accomplish structures they charge to survive. The accepted amount of acidification is abounding times faster than at atomic the accomplished 300 actor years, which included four accumulation extinctions that complex ascent ocean acidity, such as the Permian accumulation extinction, which dead 95% of abyssal species. By the end of the century, acidity changes back the automated anarchy would bout the Palaeocene-Eocene Thermal Maximum, which occurred over 5000 years and dead 35-50% of benthic foraminifera

Expected social system effects

Vulnerability of animal societies to altitude change mainly lies in the furnishings of extreme-weather contest rather than bit-by-bit altitude change.119 Impacts of altitude change so far cover adverse furnishings on baby islands,120 adverse furnishings on aboriginal populations in high-latitude areas,121 and baby but discernable furnishings on animal health.122 Over the 21st century, altitude change is acceptable to abnormally affect hundreds of millions of humans through added littoral flooding, reductions in baptize supplies, added malnutrition and added bloom impacts.123 Most bread-and-butter studies advance losses of apple gross calm artefact (GDP) for this consequence of warming.124125

Food security

See also: Altitude change and agriculture

Under present trends, by 2030, maize assembly in Southern Africa could abatement by up to 30% while rice, millet and maize in South Asia could abatement by up to 10%.126 By 2080, yields in developing countries could abatement by 10% to 25% on boilerplate while India could see a bead of 30% to 40%.127 By 2100, while the citizenry of three billion is accepted to double, rice and maize yields in the tropics are accepted to abatement by 20-40% because of college temperatures after accounting for the abatement in yields as a aftereffect of clay damp and baptize aliment fatigued by ascent temperatures.128

Future abating of about 3 °C (by 2100, about to 1990–2000) could aftereffect in added crop yields in mid- and high-latitude areas, but in low-latitude areas, yields could decline, accretion the accident of malnutrition.120 A agnate bounded arrangement of net allowances and costs could action for bread-and-butter (market-sector) effects.122 Abating aloft 3 °C could aftereffect in crop yields falling in abstemious regions, arch to a abridgement in all-around aliment production.129

Habitat inundation

See also: Altitude refugee

In baby islands and megadeltas, barrage as a aftereffect of sea akin acceleration is accepted to abuse basic basement and animal settlements. 130131 This could advance to issues of statelessness for citizenry from countries including the Maldives and Tuvalu132 and homelessness in countries with low lying areas such as Bangladesh.