Pemanasan global: Perbedaan antara revisi

'''Pemanasan global''' ({{lang-en|global warming}}); (juga disebut '''[[perubahan iklim]]''' atau [[Krisis iklim|'''[[krisis iklim]]''']]<ref>{{cite web|last=Sindo|first=Koran|date=2019-08-14|title=Gas Rumah Kaca Capai Rekor Tertinggi|url=https://today.line.me/id/v2/article/Gas+Rumah+Kaca+Capai+Rekor+Tertinggi-MvprMw|website=today.line.me|archive-date=https://web.archive.org/web/20220413212038/https://today.line.me/id/v2/article/Gas+Rumah+Kaca+Capai+Rekor+Tertinggi-MvprMw|url-status=live|access-date=2022-04-14|}}</ref>) adalah suatu proses meningkatnya [[suhu]] rata-rata [[udara]], [[atmosfer]], [[laut]], dan [[daratan]] [[Bumi]]. PadaPeriode masaperubahan laluiklim telahjuga pernah terjadi periodedi perubahanmasa iklimlalu, tetapinamun perubahan iklim yang terjadi pada saat ini jauh lebih cepat dan bukanbukanlah karenadikarenakan oleh sebab-sebab alamiah.<ref>{{harvnb|IPCC SR15 Ch1|2018|p=54|ps=: These global-level rates of human-driven change far exceed the rates of change driven by geophysical or biosphere forces that have altered the Earth System trajectory in the past…}}</ref> Sebaliknya,Penyebab perubahanutama yang menimbulkan pemanasan iklim pada saat ini disebabkan olehialah pencemaran [[gas rumah kaca]], terutama [[karbon dioksida]] (CO2) dan [[metana]]. Pembakaran [[bahan bakar fosil]] seperti [[batu bara]], [[bensin]], dan [[batu barasolar]] untuk produksi energi menciptakanialah pemasok sebagianterbesar besardari pencemaran ini. Beberapa penyebabfaktor tambahan lainnya ialah seperti praktik-sejumlah praktik [[pertanian]] tertentu, proses [[industri]], dan [[Penggundulan hutan|penggundulan hutan.]].<ref name="auto2">{{harvnb|Our World in Data, 18 September|2020}}</ref> GasKarena sifatnya yang transparan, gas rumah kaca bersifatdapat transparanditembus terhadapoleh sinar matahari, sehingga sinarmemanaskan mataharipermukaan dapatBumi. menembusnyaNamun untukketika memanaskangelombang permukaan[[ultraviolet]] bumi.dari Ketikasinar panasmatahari tersebutdiserap memantullalu didipancarkan permukaankembali bumioleh danpermukaan berubahbumi menjadi radiasi [[inframerah]], gas-gas rumah kaca tersebut menyerapnya, memerangkap panas di sekitar permukaan Bumibumi dan menyebabkan pemanasan global.

Akibat perubahan iklim, [[Penggurunan|gurun pasir]] meluas, sementara [[gelombang panas]] dan [[kebakaran hutanliar]] menjadi lebih umum.<ref>{{harvnb|IPCC SRCCL|2019|p=7|ps=: Since the pre-industrial period, the land surface air temperature has risen nearly twice as much as the global average temperature (high confidence). Climate change... contributed to desertification and land degradation in many regions (high confidence).}}; {{harvnb|IPCC SRCCL|2019|p=45|ps=: Climate change is playing an increasing role in determining wildfire regimes alongside human activity (medium confidence), with future climate variability expected to enhance the risk and severity of wildfires in many biomes such as tropical rainforests (high confidence).}}</ref> Peningkatan pemanasan di [[Kutub Utara]] telah berkontribusi pada mencairnya tanah es yang sebelumnya selalu membeku, mundurnya [[Penyusutan gletser sejak 1850|mundurnya glasial]], dan hilangnya [[es laut]].<ref>{{harvnb|IPCC SROCC|2019|p=16|ps=: Over the last decades, global warming has led to widespread shrinking of the cryosphere, with mass loss from ice sheets and glaciers (very high confidence), reductions in snow cover (high confidence) and Arctic sea ice extent and thickness (very high confidence), and increased permafrost temperature (very high confidence).}}</ref> Suhu yang lebih tinggi juga menyebabkan [[badai]] yang lebih intens, [[kekeringan]], dan cuaca ekstrem lainnya.<ref>{{Harvnb|IPCC AR6 WG1 Ch11|2021|p=1517}}</ref> Perubahan lingkungan yang cepat di pegunungan, [[terumbu karang]], dan Kutub Utara memaksa banyak spesies untuk pindah atau punah.<ref>{{cite web|author=EPA|date=19 January 2017|title=Climate Impacts on Ecosystems|url=https://19january2017snapshot.epa.gov/climate-impacts/climate-impacts-ecosystems_.html#Extinction|archive-url=https://web.archive.org/web/20180127185656/https://19january2017snapshot.epa.gov/climate-impacts/climate-impacts-ecosystems_.html#Extinction|archive-date=27 January 2018|access-date=5 February 2019|quote=Mountain and arctic ecosystems and species are particularly sensitive to climate change... As ocean temperatures warm and the acidity of the ocean increases, bleaching and coral die-offs are likely to become more frequent.|url-status=live}}</ref> Perubahan iklim mengancam manusia dengan [[kelangkaan makananair]] dan airmakanan, peningkatan [[banjir]], panas yang ekstrem, lebih banyak penyakit, dan kerugian ekonomi. Migrasi manusia dan konflik dapat terjadi sebagai akibatnya.<ref name="auto3">{{harvnb|Cattaneo|Beine|Fröhlich|Kniveton|2019}}; {{harvnb|UN Environment, 25 October|2018}}.</ref> Organisasi Kesehatan Dunia ([[WHO]]) menyebut perubahan iklim sebagai ancaman terbesar bagi [[kesehatan global]] di abad ke-21.<ref>{{harvnb|IPCC AR5 SYR|2014|pp=13–16}}; {{harvnb|WHO, Nov|2015}}: "Climate change is the greatest threat to global health in the 21st century. Health professionals have a duty of care to current and future generations. You are on the front line in protecting people from climate impacts – from more heat-waves and other extreme weather events; from outbreaks of infectious diseases such as malaria, dengue and cholera; from the effects of malnutrition; as well as treating people that are affected by cancer, respiratory, cardiovascular and other non-communicable diseases caused by environmental pollution."</ref> Bahkan jika upaya untuk meminimalkanmeminimalisir pemanasan di masa depan berhasil, beberapa [[Efek pemanasan global|efek]] akan terus berlanjut selama berabad-abad. Ini termasuk [[kenaikan permukaan laut]], dan lautan yang lebih hangat dan dengan [[pH]] yang lebih [[Peningkatan keasaman air laut|lebih asam]].<ref>{{harvnb|IPCC SR15 Ch1|2018|p=64|ps=: Sustained net zero anthropogenic emissions of {{CO2}} and declining net anthropogenic non-{{CO2}} radiative forcing over a multi-decade period would halt anthropogenic global warming over that period, although it would not halt sea level rise or many other aspects of climate system adjustment.}}</ref>

Banyak dari dampak-dampak ini telah dirasakan pada tingkat pemanasan 1,2 {{Nbsp}}°C (2,2 °F) saat ini. Peningkatan pemanasan lebih lanjut akan memperbesar dampak-dampak ini dan dapat memicu terjadinya titik kritis, seperti mencairnya [[lapisan es Greenland]].<ref>{{harvnb|IPCC AR6 WG1 Technical Summary|2021|p=71}}</ref> Di bawah Perjanjian[[Persetujuan Paris]] pada tahun 2015, negara-negara secara kolektif sepakat untuk menjaga agar pemanasan tetap " berada di bawah 2 {{Nbsp}}°C". Namun, dengan komitmen yang dibuat di bawah Perjanjianpersetujuan tersebut, pemanasan global masih akan mencapai sekitar 2,7 {{Nbsp}}°C (4,9 °F) pada akhir abad ini.<ref name="UNEP2021">{{harvnb|United Nations Environment Programme|2021|p=36|ps=: "A continuation of the effort implied by the latest unconditional NDCs and announced pledges is at present estimated to result in warming of about 2.7&nbsp;°C (range: 2.2–3.2&nbsp;°C) with a 66 per cent chance."}}</ref> Membatasi pemanasan hingga 1,5 {{Nbsp}}°C akan membutuhkan pengurangan separuh dari tingkat [[emisi karbon]] pada tahun 2030 dan mencapai nol emisi[[netralitas karbon]] pada tahun 2050.<ref>{{harvnb|IPCC SR15 Ch2|2018|pp=95–96|ps=: In model pathways with no or limited overshoot of 1.5&nbsp;°C, global net anthropogenic {{CO2}} emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range)}}; {{harvnb|IPCC SR15|2018|loc=SPM C.3|p=17|ps=:All pathways that limit global warming to 1.5&nbsp;°C with limited or no overshoot project the use of carbon dioxide removal (CDR) on the order of 100–1000 GtCO2 over the 21st century. CDR would be used to compensate for residual emissions and, in most cases, achieve net negative emissions to return global warming to 1.5&nbsp;°C following a peak (high confidence). CDR deployment of several hundreds of GtCO2 is subject to multiple feasibility and sustainability constraints (high confidence).}}; {{harvnb|Rogelj|Meinshausen|Schaeffer|Knutti|Riahi|2015}}; {{harvnb|Hilaire et al.|2019}}</ref>

Terdapat [[hipotesis]] yang menyatakan bahwa variasi dari [[matahari]], dengan kemungkinan diperkuat oleh [[umpan balik]] dari [[awan]], dapat memberi kontribusi dalam pemanasan saat ini.<ref>{{cite journal | first=Nigel | last=Marsh | coauthors=Henrik, Svensmark | title=Cosmic Rays, Clouds, and Climate | journal=Space Science Reviews | volume=94 | number=1-2 | pages=215-230 | year=2000 | month=November | url=http://www.dsri.dk/~hsv/SSR_Paper.pdf | format=[[Portable Document Format|PDF]] | doi=10.1023/A:1026723423896 | accessdate=17-04-2007 | archive-date=2008-05-27 | archive-url=https://web.archive.org/web/20080527234228/http://www.dsri.dk/~hsv/SSR_Paper.pdf | dead-url=yes | issn=0038-6308}}</ref> Perbedaan antara mekanisme ini dengan pemanasan akibat [[efek rumah kaca]] adalah meningkatnya aktivitas [[matahari]] akan memanaskan [[stratosfer]] sebaliknya [[efek rumah kaca]] akan mendinginkan [[stratosfer]]. Pendinginan [[stratosfer]] bagian bawah paling tidak telah diamati sejak tahun 1960,<ref>{{cite web|title=Climate Change 2001:Working Group I: The Scientific Basis (Fig. 2.12)|url=http://www.grida.no/climate/ipcc_tar/wg1/fig2-12.htm|date=2001|accessdate=08-05-2007|archive-date=2016-06-02|archive-url=https://web.archive.org/web/20160602235858/http://www.grida.no/climate/ipcc_tar/wg1/fig2-12.htm|dead-url=yes}}</ref> yang tidak akan terjadi bila aktivitas [[matahari]] menjadi kontributor utama pemanasan saat ini. Penipisan [[lapisan ozon]] juga dapat memberikan efek pendinginan tersebut tetapi penipisan tersebut terjadi mulai akhir tahun [[1970-an]]. Fenomena [[variasi Matahari]] dikombinasikan dengan aktivitas [[gunung berapi]] mungkin telah memberikan efek pemanasan dari masa pra-industri hingga tahun 1950, serta efek pendinginan sejak tahun 1950.<ref>{{cite web | url=http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf | format=[[Portable Document Format|PDF]] | title=Understanding and Attributing Climate Change | work=Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change | accessdate=20-05-2007 | date=07-05-2007 | publisher=[[Intergovernmental Panel on Climate Change]] | last=Hegerl | first=Gabriele C. | coauthors=''et al.'' | pages=690 | quote=Recent estimates (Figure 9.9) indicate a relatively small combined effect of natural forcings on the global mean temperature evolution of the seconds half of the 20th century, with a small net cooling from the combined effects of solar and volcanic forcings | archive-date=2018-05-08 | archive-url=https://web.archive.org/web/20180508152907/http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf | dead-url=yes }}</ref><ref>{{cite journal | last=Ammann | first = Caspar | coauthors =''et al.'' | date=06-04-2007 | title=Solar influence on climate during the past millennium: Results from ransient simulations with the NCAR Climate Simulation Model | journal=Proceedings of the National Academy of Sciences of the United States of America | volume=104 | issue=10 | pages=3713-3718 | url=http://www.pnas.org/cgi/reprint/104/10/3713 | quote=However, because of a lack of interactive ozone, the model cannot fully simulate features discussed in (44)." "While the NH temperatures of the high-scaled experiment are often colder than the lower bound from proxy data, the modeled decadal-scale NH surface temperature for the medium-scaled case falls within the uncertainty range of the available temperature reconstructions. The medium-scaled simulation also broadly reproduces the main features seen in the proxy records." "Without anthropogenic forcing, the 20th century warming is small. The simulations with only natural forcing components included yield an early 20th century peak warming of ≈0.2&nbsp;°C (≈1950 AD), which is reduced to about half by the end of the century because of increased volcanism.}}

Perubahan tinggi rata-rata muka laut diukur dari daerah dengan lingkungan yang stabil secara geologi.]]

* [http://www.physicsmail.org/history/climate/index.html Climate Change: Discovery of Global Warming] {{Webarchive|url=https://web.archive.org/web/20120819103911/http://www.physicsmail.org/history/climate/index.html |date=2012-08-19 }}