科學家們努力尋找以及確定地球近期天氣變化的歸因(英語:Attribution of recent climate change),發現導致變化的主要驅動因素是人類活動產生的溫室氣體水平升高,加上自然力量讓變率增強。人類在2010-2019年間造成的地表溫度,比1850-1900年的水平大約高出0.8至1.3°C之間,最佳的估計平均值為1.07°C。那段時間經各式溫室氣體導致的溫度升高在1.0至2.0°C之間,由其他人類因素(主要是氣膠)導致的冷卻在0.0至0.8°C之間,自然因素導致的溫度變化在-0.1至+0.1°C之間,而氣候本身變率導致的溫度變化在-0.2至+0.2°C之間。[4]
在過去5年中,地球表面變暖程度大約達到0.65°C (1.17°F)(參見儀器測量地表溫度(英语:Instrumental temperature record))。會導致全球平均溫度變化的因素包括氣候系統的內部變率、外部強迫、溫室氣體濃度增加,或是前述因素的任意組合。目前的研究顯示溫室氣體(尤其是二氧化碳)的增加是造成變暖的主要原因。此一結論的證據有:
這種指紋工作正大量轉移其重點。如前所述的明確而令人信服的科學證據已證明人類對全球氣候產生顯著影響。最近大部分的重點著重於大陸和區域性的氣候變化,以及可能對社會產生重大影響的變量之上。例如科學家已找出人類活動與積雪(英语:snowpack)變化、最高和最低溫度(晝夜溫度差異(英语:Diurnal air temperature variation))以及美國西部山區徑流的季節性時點的因果關係。人類活動可能對熱帶氣旋形成區的海洋表面溫度變化造成重大影響。研究人員也在超越物理氣候系統的範圍外,開始將植物和動物物種的分佈和季節性行為的變化,與人類引起的溫度和降水變化做聯繫。[53]
美國喬治梅森大學於2011年發表在《國際輿論研究雜誌(英语:International Journal of Public Opinion Research)》上的一篇標題為“氣候變化科學觀點的結構(The Structure of Scientific Opinion on Climate Change)”收集地球、太空、大氣、海洋或水文科學領域科學家的觀點。[71]研究發現489名受訪者中(佔所有符合特定調查標準人數中的近一半,均在學術界、政府和工業界服務,且為著名專業組織的成員)[71]有97%的人同意全球氣溫在過去一個世紀裡已經上升。[71]此外,其中84%的人同意“人類引起的溫室效應導致變暖”正在發生。[71]只有5%的人不同意人類活動是全球變暖的重要原因。[71]
檢測和歸因研究
IPCC第四次評估報告的結論是可對一些檢測到的氣候變化進行歸因(參見氣候變化的影響(英语:Effects of climate change))。但評估較小區域(小於大陸的尺度)和短時間段(小於50年)的變化歸因時,會更為困難。[45]
在較大的區域,平均作用可把氣候的自然變率降低,讓檢測和歸因更容易進行。
1996年,包含本傑明·D·桑特 (Benjamin D. Santer(英语:Benjamin D. Santer))等研究人員在《科學》雜誌上發表一篇題為“尋找人類對大氣熱結構的影響(A search for human influences on the thermal structure of the atmosphere)”的論文。寫道:“觀察到的1963年至1987年自由大氣溫度變化的空間模式,與最先進的氣候模型預測結果相似,這些模式包含二氧化碳、人為硫酸鹽氣膠和平流層臭氧濃度變化的各種組合。在此期間,模型和檢測之間的模式相似度增加。這種趨勢很可能部分歸因於人類活動,但仍然存在許多不確定性,特別是與自然變率的估計有關。“[73]
Committee on the Science of Climate Change, US National Research Council. Summary. Climate Change Science: An Analysis of Some Key Questions. Washington, D.C., US: National Academies Press. 2001: 1–3 [2011-05-20]. ISBN 0-309-07574-2. doi:10.17226/10139. (原始内容存档于2011-06-05). "The IPCC's conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue" (page 3).
Committee on the Science of Climate Change, US National Research Council. 2. Natural Climatic Variations. Climate Change Science: An Analysis of Some Key Questions. Washington, D.C., US: National Academies Press. 2001: 8 [2011-05-20]. ISBN 0-309-07574-2. doi:10.17226/10139. (原始内容存档于2011-09-27).
Committee on the Science of Climate Change, US National Research Council. 2. Natural Climatic Variations. Climate Change Science: An Analysis of Some Key Questions. Washington, D.C., US: National Academies Press. 2001: 8 [2011-05-20]. ISBN 0-309-07574-2. doi:10.17226/10139. (原始内容存档于2011-09-27).
Steinfeld, Henning; Gerber, Pierre; Wassenaar, Tom; Castel, Vincent; Rosales, Mauricio; de Haan, Cees. Livestock's Long Shadow(PDF). Food and Agricultural Organization of the U.N. 2006. ISBN 9251055718. (原始内容(PDF)存档于2008-06-25).
In the IPCC Fourth Assessment Report, the following scale is used to quantify uncertainty: "virtually certain" >99%; "extremely likely" >95%; "very likely" >90%; "likely" >66%; "more likely than not" >50%; "about as likely as not" 33 to 66%; "unlikely" <33%; "very unlikely" <10%; "extremely unlikely" <5%; "exceptionally unlikely" <1%. Solomon, S.; et al, Box TS.1: Treatment of Uncertainties in the Working Group I Assessment, Technical Summary, [18 August 2012], (原始内容存档于12 June 2012), in IPCC AR4 WG1 2007.
Cook, John; Oreskes, Naomi; Doran, Peter T.; Anderegg, William R. L.; et al. Consensus on consensus: a synthesis of consensus estimates on human-caused global warming. Environmental Research Letters. 2016, 11 (4): 048002. Bibcode:2016ERL....11d8002C. doi:10.1088/1748-9326/11/4/048002.
Lynas, Mark; Houlton, Benjamin Z.; Perry, Simon. Greater than 99% consensus on human caused climate change in the peer-reviewed scientific literature. Environmental Research Letters. 2021-10-19, 16 (11): 114005. Bibcode:2021ERL....16k4005L. S2CID 239032360. doi:10.1088/1748-9326/ac2966.
Myers, Krista F.; Doran, Peter T.; Cook, John; Kotcher, John E.; Myers, Teresa A. Consensus revisited: quantifying scientific agreement on climate change and climate expertise among Earth scientists 10 years later. Environmental Research Letters. 2021-10-20, 16 (10): 104030. Bibcode:2021ERL....16j4030M. S2CID 239047650. doi:10.1088/1748-9326/ac2774.
Committee on Surface Temperature Reconstructions for the Last 2000 Years. Overview. Surface Temperature Reconstructions for the Last 2,000 Years. Washington, D.C., US: National Academies Press. 2006: 21–22 [2011-05-20]. ISBN 0-309-66144-7. doi:10.17226/11676. (原始内容存档于2012-10-17).
Panel on Advancing the Science of Climate Change US National Research Council. Summary. Advancing the Science of Climate Change. Washington, D.C., US: National Academies Press. 2010: 3 [20 May 2011]. ISBN 978-0-309-14588-6. doi:10.17226/12782. (原始内容存档于2011-01-27).
Farnsworth, S. J. The Structure of Scientific Opinion on Climate Change. International Journal of Public Opinion Research. 2011, 24: 93–103. doi:10.1093/ijpor/edr033. Referred to by: Wihbey, J. Structure of Scientific Opinion on Climate Change. Journalist's Resource: Research for Reporting. A project of the Harvard Kennedy School's Shorenstein Center and the Carnegie-Knight Initiative. 2011-11-04 [2012-08-18]. (原始内容存档于2020-11-11).
Committee on Surface Temperature Reconstructions for the Last 2000 Years US National Research Council. 10. Climate Forcings and Climate Models. Surface Temperature Reconstructions for the Last 2,000 Years. Washington, D.C., US: National Academies Press. 2006: 109 [2011-06-23]. ISBN 0-309-66144-7. doi:10.17226/11676. (原始内容存档于2010-06-13).
Abdussamatov, Habibullo I. About the long-term coordinated variations of the activity, radius, total irradiance of the Sun and the Earth's climate. Proceedings of the International Astronomical Union. June 2004, 223: 541–542. Bibcode:2004IAUS..223..541A. doi:10.1017/S1743921304006775. "The main cause of climate change during the last millennia is the corresponding cyclic variation of the 80- and 200-year component of irradiance correlated with activity. That is why, the contemporary (climate change) is not anomalous but is ordinary secular global warming."
US Environmental Protection Agency. 3.2.2 Solar Irradiance. Volume 3: Attribution of Observed Climate Change. Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act. EPA's Response to Public Comments. US Environmental Protection Agency. 2009 [2011-06-23]. (原始内容存档于2011-06-16).
IPCC. Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S. L.; et al , 编. Climate Change 2021: The Physical Science Basis(PDF). Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press (In Press). 2021 [2023-06-10]. (原始内容存档(PDF)于2021-08-13).
Cook, J.; et al, Quantifying the consensus on anthropogenic global warming in the scientific literature, Environmental Research Letters, 2013, 8 (2): 024024, Bibcode:2013ERL.....8b4024C, doi:10.1088/1748-9326/8/2/024024. Open-access article.
IPCC TAR WG1, Houghton, J.T.; Ding, Y.; Griggs, D.J.; Noguer, M.; van der Linden, P.J.; Dai, X.; Maskell, K.; Johnson, C.A. , 编, Climate Change 2001: The Scientific Basis, Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, 2001 [2019-12-18], ISBN 0-521-80767-0, (原始内容存档于2019-12-15) 含有內容需登入查看的頁面 (link) (pb: 0-521-01495-6).
Pittock, B., Can solar variations explain variations in the Earth's climate? An editorial comment, Climatic Change, October 2009, 96 (4): 483–487, doi:10.1007/s10584-009-9645-8, pp. 483–487. Referred to by EPA 2009: EPA's Response to Public Comments, 3: Attribution of Observed Climate Change, Response 3-36, in Sec 3.2.2 Solar Irradiance
本条目引用的公有领域材料。材料来自US Global Change Research Program (USGCRP)的文档:Karl, T.R.; Melillo. J.; Peterson, T.; Hassol, S.J. (编). Global Climate Change Impacts in the United States(PDF). Cambridge University Press. 2009 [2017-12-13]. ISBN 978-0-521-14407-0. (原始内容存档(PDF)于2019-11-15).. Public-domain status of this report can be found on p.4 of source