Editing Alexandria (section)

==== Climate change ====
A 2019 paper published in [[PLOS One]] estimated that under [[Representative Concentration Pathway#4.5|Representative Concentration Pathway 4.5]], a "moderate" scenario of [[climate change]] where global warming reaches ~{{convert|2.5-3|C-change|F-change}} by 2100, the climate of Alexandria in the year 2050 would most closely resemble the current climate of [[Gaza City]]. The annual temperature would increase by {{convert|2.8|C-change|F-change}}, and the temperature of the warmest and the coldest month by {{convert|2.9|C-change|F-change}} and {{convert|3.1|C-change|F-change}}.<ref>{{cite journal |last1=Bastin |first1=Jean-Francois |last2=Clark |first2=Emily |last3=Elliott |first3=Thomas |last4=Hart |first4=Simon |last5=van den Hoogen |first5=Johan |last6=Hordijk |first6=Iris |last7=Ma |first7=Haozhi |last8=Majumder |first8=Sabiha |last9=Manoli |first9=Gabriele |last10=Maschler |first10=Julia |last11=Mo |first11=Lidong |last12=Routh |first12=Devin |last13=Yu |first13=Kailiang |last14=Zohner |first14=Constantin M. |last15=Thomas W. |first15=Crowther |title=Understanding climate change from a global analysis of city analogues |journal=PLOS ONE |date=10 July 2019 |volume=14 |issue=7 |at=S2 Table. Summary statistics of the global analysis of city analogues. |doi=10.1371/journal.pone.0217592 |pmid=31291249 |pmc=6619606 |bibcode=2019PLoSO..1417592B |doi-access=free }}</ref><ref>{{cite web |url=https://crowtherlab.pageflow.io/cities-of-the-future-visualizing-climate-change-to-inspire-action |title=Cities of the future: visualizing climate change to inspire action |at=Current vs. future cities |access-date=8 January 2023 |archive-date=8 January 2023 |archive-url=https://web.archive.org/web/20230108082440/https://crowtherlab.pageflow.io/cities-of-the-future-visualizing-climate-change-to-inspire-action |url-status=dead }}</ref> According to [[Climate Action Tracker]], the current warming trajectory appears consistent with {{convert|2.7|C-change|F-change}}, which closely matches RCP 4.5.<ref>{{cite web |url=https://climateactiontracker.org/global/cat-thermometer/ |title=The CAT Thermometer |access-date=8 January 2023}}</ref>

Due to its location on a Nile river delta, Alexandria is one of the most vulnerable cities to [[sea level rise]] in the entire world. According to some estimates, hundreds of thousands of people in its low-lying areas may already have to be relocated before 2030.<ref>{{cite news |url=https://www.theguardian.com/global-development/2018/aug/29/alexandria-little-venice-egypt-climate-change-frontline|title=Houses claimed by the canal: life on Egypt's climate change frontline| last=Michaelson| first=Ruth|date=25 August 2018|work=[[The Guardian]]|access-date=30 August 2018}}</ref> The 2022 [[IPCC Sixth Assessment Report]] estimates that by 2050, Alexandria and 11 other major African cities ([[Abidjan]], [[Algiers]], [[Cape Town]], [[Casablanca]], [[Dakar]], [[Dar es Salaam]], [[Durban]], [[Lagos]], [[Lomé]], [[Luanda]] and [[Maputo]]) would collectively sustain cumulative damages of US$65 billion for the "moderate" climate change scenario [[Representative Concentration Pathway|RCP 4.5]] and US$86.5 billion for the high-emission scenario RCP 8.5, while RCP 8.5 combined with the hypothetical impact from [[marine ice sheet instability]] at high levels of warming would involve up to US$137.5 billion in damages. Additional accounting for the "low-probability, high-damage events" may increase aggregate risks to US$187 billion for the "moderate" RCP4.5, US$206 billion for RCP8.5 and US$397 billion under the high-end ice sheet instability scenario. In every single estimate, Alexandria alone bears around half of these costs.<ref>Trisos, C.H., I.O. Adelekan, E. Totin, A. Ayanlade, J. Efitre, A. Gemeda, K. Kalaba, C. Lennard, C. Masao, Y. Mgaya, G. Ngaruiya, D. Olago, N.P. Simpson, and S. Zakieldeen 2022: [https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Chapter09.pdf Chapter 9: Africa]. In [https://www.ipcc.ch/report/ar6/wg2/ Climate Change 2022: Impacts, Adaptation and Vulnerability] [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke,V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, US, pp. 2043–2121</ref> Since sea level rise would continue for about 10,000 years under every scenario of climate change, future costs of sea level rise would only increase, especially without adaptation measures.<ref>{{cite book |url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Full_Report.pdf |title=Technical Summary. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change |date=August 2021 |publisher=IPCC |page=TS14 |access-date=12 November 2021}}</ref> Recent studies published in [[Earth's Future]] by the [[American Geophysical Union]] indicate that rising sea levels are causing increases in coastal aquifer levels, reaching building foundations and accelerating their corrosion and potential collapse. The study predicts that in 2025, more than 7000 buildings in Alexandria will be at risk of collapse due to these groundwater processes.<ref>{{cite journal |last1=Fouad |first1=Sara S. |last2=Heggy |first2=Essam |last3=Amrouni |first3=Oula |last4=Hzami |first4=Abderraouf |last5=Nijhuis |first5=Steffen |last6=Mohamed |first6=Nesma |last7=Saleh |first7=Ibrahim H. |last8=Jomaa |first8=Seifeddine |last9=Elsheshtawy |first9=Yasser |last10=Weilacher |first10=Udo |title=Soaring Building Collapses in Southern Mediterranean Coasts: Hydroclimatic Drivers & Adaptive Landscape Mitigations |journal=Earth's Future |date=12 February 2025 |volume=13 |issue=2 |doi=10.1029/2024EF004883 |doi-access=free|bibcode=2025EaFut..1304883F }}</ref>