Editing Albedo (section)

===Changes to albedo due to human activities===
[[File:2000- Albedo (reflectivity) of Earth.svg|thumb|Earth's albedo as monitored by the [[Clouds and the Earth's Radiant Energy System|CERES]] satellite system shows a darkening of Earth that has caused 1.7{{nbsp}}W/m<sup>2</sup> warming since 2010.<ref name=Hansen_20250203/> That amount, only some of which is [[Radiative forcing|climate forcing]], is equivalent to a 138 ppm increase of atmospheric carbon dioxide.<ref name=Hansen_20250203>{{cite journal |last1=Hansen |first1=James E. |last2=Kharecha |first2=Pushker |last3=Sato |first3=Makiko |last4=Tselioudis |first4=George |last5=Kelly |first5=Joseph |last6=Bauer |first6=Susanne E. |last7=Ruedy |first7=Reto |last8=Jeong |first8=Eunbi |last9=Jin |first9=Quijian |last10=Rignot |first10=Eric |last11=Velicogna |first11=Isabella |last12=Schoeberl |first12=Mark R. |last13=von Schuckmann |first13=Karina |last14=Amponsem |first14=Joshua |last15=Cao |first15=Junji |last16=Keskinen |first16=Anton |last17=Li |first17=Jing |last18=Pokela |first18=Anni |title=Global Warming Has Accelerated: Are the United Nations and the Public Well-Informed? |journal=Environment |date=3 February 2025 |volume=67 |issue=1 |pages=6–44 |doi=10.1080/00139157.2025.2434494|doi-access=free |bibcode=2025ESPSD..67....6H }} Figure 6.</ref>]]
[[File:ISS041-E-90107 - View of Spain.jpg|thumb|Greenhouses of El Ejido, Almería, Spain]]
Human activities (e.g., deforestation, farming, and urbanization) change the albedo of various areas around the globe.<ref>{{Cite journal |last1=Sagan |first1=Carl |last2=Toon |first2=Owen B. |last3=Pollack |first3=James B. |date=1979 |title=Anthropogenic Albedo Changes and the Earth's Climate |journal=Science |volume=206 |issue=4425 |pages=1363–1368 |bibcode=1979Sci...206.1363S |doi=10.1126/science.206.4425.1363 |issn=0036-8075 |jstor=1748990 |pmid=17739279 |s2cid=33810539}}</ref> [[Human impact on the environment|Human impacts]] to "the physical properties of the land surface can perturb the climate by altering the Earth’s radiative energy balance" even on a small scale or when undetected by satellites.<ref name=":0">{{Cite journal |last1=Campra |first1=Pablo |last2=Garcia |first2=Monica |last3=Canton |first3=Yolanda |last4=Palacios-Orueta |first4=Alicia |date=2008 |title=Surface temperature cooling trends and negative radiative forcing due to land use change toward greenhouse farming in southeastern Spain |journal=Journal of Geophysical Research |volume=113 |issue=D18 |bibcode=2008JGRD..11318109C |doi=10.1029/2008JD009912 |doi-access=free}}</ref>

[[Urbanization]] generally decreases albedo (commonly being 0.01–0.02 lower than adjacent [[croplands]]), which contributes to [[global warming]]. Deliberately increasing albedo in urban areas can mitigate the [[urban heat island]] effect. An estimate in 2022 found that on a global scale, "an albedo increase of 0.1 in worldwide urban areas would result in a cooling effect that is equivalent to absorbing ~44 [[Gigatons|Gt]] of CO<sub>2</sub> emissions."<ref>{{Cite journal |last1=Ouyang |first1=Zutao |last2=Sciusco |first2=Pietro |last3=Jiao |first3=Tong |last4=Feron |first4=Sarah |last5=Li |first5=Cheyenne |last6=Li |first6=Fei |last7=John |first7=Ranjeet |last8=Peilei |first8=Fan |last9=Li |first9=Xia |last10=Williams |first10=Christopher A. |last11=Chen |first11=Guangzhao |last12=Wang |first12=Chenghao |last13=Chen |first13=Jiquan |date=July 2022 |title=Albedo changes caused by future urbanization contribute to global warming |journal=Nature Communications |volume=13 |issue=1 |page=3800 |bibcode=2022NatCo..13.3800O |doi=10.1038/s41467-022-31558-z |pmc=9249918 |pmid=35778380}}</ref>

Intentionally enhancing the albedo of the Earth's surface, along with its daytime [[thermal emittance]], has been proposed as a [[Solar Radiation Management|solar radiation management]] strategy to mitigate [[Energy crisis|energy crises]] and global warming known as [[passive daytime radiative cooling]] (PDRC).<ref name=":1">{{Cite journal |last1=Wang |first1=Tong |last2=Wu |first2=Yi |last3=Shi |first3=Lan |last4=Hu |first4=Xinhua |last5=Chen |first5=Min |last6=Wu |first6=Limin |date=2021 |title=A structural polymer for highly efficient all-day passive radiative cooling |journal=Nature Communications |volume=12 |issue=365 |page=365 |doi=10.1038/s41467-020-20646-7 |pmc=7809060 |pmid=33446648 |quote=Accordingly, designing and fabricating efficient PDRC with sufficiently high solar reflectance (𝜌¯solar) (λ ~ 0.3–2.5 μm) to minimize solar heat gain and simultaneously strong LWIR thermal emittance (ε¯LWIR) to maximize radiative heat loss is highly desirable. When the incoming radiative heat from the Sun is balanced by the outgoing radiative heat emission, the temperature of the Earth can reach its steady state.}}</ref><ref name=":5">{{Cite journal |last1=Chen |first1=Meijie |last2=Pang |first2=Dan |last3=Chen |first3=Xingyu |last4=Yan |first4=Hongjie |last5=Yang |first5=Yuan |date=October 2021 |title=Passive daytime radiative cooling: Fundamentals, material designs, and applications |journal=EcoMat |volume=4 |doi=10.1002/eom2.12153 |s2cid=240331557 |quote=Passive daytime radiative cooling (PDRC) dissipates terrestrial heat to the extremely cold outer space without using any energy input or producing pollution. It has the potential to simultaneously alleviate the two major problems of energy crisis and global warming. |doi-access=free }}</ref><ref name=":02">{{Cite journal |last=Munday |first=Jeremy |date=2019 |title=Tackling Climate Change through Radiative Cooling |journal=Joule |volume=3 |issue=9 |pages=2057–2060 |doi=10.1016/j.joule.2019.07.010 |s2cid=201590290 |doi-access=free|bibcode=2019Joule...3.2057M }}</ref> Efforts toward widespread implementation of PDRCs may focus on maximizing the albedo of surfaces from very low to high values, so long as a thermal emittance of at least 90% can be achieved.<ref name=":22">{{Cite journal |last1=Anand |first1=Jyothis |last2=Sailor |first2=David J. |last3=Baniassadi |first3=Amir |date=February 2021 |title=The relative role of solar reflectance and thermal emittance for passive daytime radiative cooling technologies applied to rooftops |url=https://www.sciencedirect.com/science/article/abs/pii/S2210670720308295 |journal=Sustainable Cities and Society |volume=65 |page=102612 |doi=10.1016/j.scs.2020.102612 |bibcode=2021SusCS..6502612A |s2cid=229476136 |quote=Thus, as manufactures consider development of PDRC materials for building applications, their efforts should disproportionately focus on increasing surface solar reflectance (albedo) values, while retaining the conventional thermal emissivity. |via=Elsevier Science Direct}}</ref>

The tens of thousands of [[hectare]]s of greenhouses in [[Province of Almería|Almería, Spain]] form a large expanse of whitened plastic roofs. A 2008 study found that this anthropogenic change lowered the local surface area temperature of the high-albedo area, although changes were localized.<ref name=":0" /> A follow-up study found that "CO2-eq. emissions associated to changes in surface albedo are a consequence of land transformation" and can reduce surface temperature increases associated with climate change.<ref>{{Cite journal |last1=Muñoz |first1=Ivan |last2=Campra |first2=Pablo |date=2010 |title=Including CO2-emission equivalence of changes in land surface albedo in life cycle assessment. Methodology and case study on greenhouse agriculture |url=https://www.researchgate.net/publication/226490855 |journal=Int J Life Cycle Assess |volume=15 |issue=7 |pages=679–680 |bibcode=2010IJLCA..15..672M |doi=10.1007/s11367-010-0202-5 |s2cid=110705003 |via=Research Gate}}</ref>