Query: But the heads of small island nations, fearful of rising sea levels, had also asked scientists to examine the effects of 2.7 degrees of warming.

Relevant passages:
Effects of global warming <=SEP=> The effects of global warming are the environmental and social changes caused ( directly or indirectly ) by human emissions of greenhouse gases . There is a scientific consensus that climate change is occurring , and that human activities are the primary driver . Many impacts of climate change have already been observed , including glacier retreat , changes in the timing of seasonal events ( e.g. , earlier flowering of plants ) , and changes in agricultural productivity .   Future effects of climate change will vary depending on climate change policies and social development . The two main policies to address climate change are reducing human greenhouse gas emissions ( climate change mitigation ) and adapting to the impacts of climate change . Geoengineering is another policy option .   Near-term climate change policies could significantly affect long-term climate change impacts . Stringent mitigation policies might be able to limit global warming ( in 2100 ) to around 2 ° C or below , relative to pre-industrial levels . Without mitigation , increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 ° C. Higher magnitudes of global warming would be more difficult to adapt to , and would increase the risk of negative impacts .

Tuvalu <=SEP=> Tuvalu ( -LSB- tᵿˈvɑːlu -RSB- or -LSB- ˈtuːvəˌluː -RSB- ) , formerly known as the Ellice Islands , is a Polynesian island nation located in the Pacific Ocean , about midway between Hawaii and Australia , lying east-northeast of the Santa Cruz Islands ( belonging to the Solomons ) , southeast of Nauru , south of Kiribati , west of Tokelau , northwest of Samoa and Wallis and Futuna and north of Fiji . It comprises three reef islands and six true atolls spread out between the latitude of 5 ° to 10 ° south and longitude of 176 ° to 180 ° , west of the International Date Line . Tuvalu has a population of 10,640 ( 2012 census ) . The total land area of the islands of Tuvalu is 26 km2 .   The first inhabitants of Tuvalu were Polynesians . The pattern of settlement that is believed to have occurred is that the Polynesians spread out from Samoa and Tonga into the Tuvaluan atolls , with Tuvalu providing a stepping stone to migration into the Polynesian Outlier communities in Melanesia and Micronesia .   In 1568 , Spanish navigator Álvaro de Mendaña was the first European to sail through the archipelago , sighting the island of Nui during his expedition in search of Terra Australis . In 1819 the island of Funafuti was named Ellice 's Island ; the name Ellice was applied to all nine islands after the work of English hydrographer Alexander George Findlay . The islands came under Britain 's sphere of influence in the late 19th century , when each of the Ellice Islands was declared a British Protectorate by Captain Gibson of between 9 and 16 October 1892 . The Ellice Islands were administered as British protectorate by a Resident Commissioner from 1892 to 1916 as part of the British Western Pacific Territories ( BWPT ) , and then as part of the Gilbert and Ellice Islands colony from 1916 to 1974 .   A referendum was held in December 1974 to determine whether the Gilbert Islands and Ellice Islands should each have their own administration . As a consequence of the referendum , the Gilbert and Ellice Islands colony ceased to exist on 1 January 1976 and the separate British colonies of Kiribati and Tuvalu came into existence . Tuvalu became fully independent within the Commonwealth on 1 October 1978 . On 5 September 2000 Tuvalu became the 189th member of the United Nations .

Regional effects of global warming <=SEP=> Regional effects of global warming are long-term significant changes in the expected patterns of average weather of a specific region due to global warming . The world average temperature is rising due to the greenhouse effect caused by increasing levels of greenhouse gases , especially carbon dioxide . When the global temperature changes , the changes in climate are not expected to be uniform across the Earth . In particular , land areas change more quickly than oceans , and northern high latitudes change more quickly than the tropics , and the margins of biome regions change faster than do their cores .   Regional effects of global warming vary in nature . Some are the result of a generalised global change , such as rising temperature , resulting in local effects , such as melting ice . In other cases , a change may be related to a change in a particular ocean current or weather system . In such cases , the regional effect may be disproportionate and will not necessarily follow the global trend . The increasing temperatures from greenhouse gases have been causing sea levels to rise for many years .   There are three major ways in which global warming will make changes to regional climate : melting or forming ice , changing the hydrological cycle ( of evaporation and precipitation ) and changing currents in the oceans and air flows in the atmosphere . The coast can also be considered a region , and will suffer severe impacts from sea level rise .

Global warming <=SEP=> Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years .   In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing .   Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years .   Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) ,  whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change .   Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned .