On Albedo

Albedo is a measure of reflected incoming radiation. It’s extremely vital in climate science, and so it’s important to know what it actually is, and what its trend was.

I was taught in school that albedo is 0.3. NASA’s Earth Factsheet lists it as 0.306. I have always used 0.3 for quick calculations. Most climate science guides on the internet also use this value.

The history of albedo-finding is shown in this paper:

History of Albedo

The history generally shows a reduction in albedo. The real question is: is albedo actually reducing, or is our measurement techniques refining?

This matters a great deal, because:

A drop of as little as 0.01 in Earth’s albedo would have a major warming influence on climate—roughly equal to the effect of doubling the amount of carbon dioxide in the atmosphere, which would cause Earth to retain an additional 3.4 watts of energy for every square meter of surface area.


The radiative forcing formula to make the above quote true would have to be:

Forcing = 4.906 * ln(new_co2 / old_co2)   { W/m² }

Because 4.906*ln(2) = 3.4. IPCC uses the value of 5.35 rather than 4.906, but I have to go with NASA here.

co2levels.org reminds us that CO2 concentration has increased from ~370ppm in 2000 to ~420ppm today. The theoretical forcing since 2000 would be:

4.906*ln(420/370) = 0.622 W/m²

Back to albedo …

The best available albedo data from 2000 to 2021 is available from CERES ( “the only project worldwide whose prime objective is to produce global climate data records of Earth’s Radiation Budget” ). You can download it here, after you register here. Here is what the data shows:

Albedo Change 2000 - Now:
0.2929 - 0.2891 = 0.0038

The theoretical albedo forcing would thus be

3.4 * 0.0038/0.01 = 1.292 W/m²

Thus the albedo forcing is twice as high as CO2!

It’s because it’s twice as high that the IPCC and other climate change advocacy groups do not use albedo at all. They refer to surface albedo, which favors slight cooling, but not to the atmospheric albedo which would ruin their neat narrative.

IPCC, AR5 Figure 8.17

The atmospheric albedo forcing from 2000 to 2021 is ~77% of the entire theoretical CO2 forcing from 1750 to just before that report was issued in 2013.

Think about it. Take care. -Zoe


# Zoe Phin, 20201/06/01
# File: alb.sh
# Run: . alb.sh; require; download; plot

require() { sudo apt-get install -y nco gmt gnuplot; }

download() { echo "	No automated download. Follow instructions:
    Register Account at: https://urs.earthdata.nasa.gov/
    Manually Download with a web browser:
    Then move file to this directory."

plot() {
    cmd="ncks CERES_EBAF-TOA_Edition4.1_200003-202103.nc"
    $cmd -v gtoa_sw_all_mon --trd -HC | sed \$d | awk -F= '{print $3}' > .swa
    $cmd -v gsolar_mon --trd -HC | sed \$d | awk -F= '{print $3}' > .sun
    paste -d ' ' .swa .sun | awk '{	printf "%.3f %.4f\n", 
        2000+1/6+NR/12+1/24, $1/$2 }' | gmt gmtregress | sed 1d | tee .plt | sed -n '1p;$p' | awk '{
            printf "%.4f ", $3} END {print ""} ' | awk '{print $1" - "$2" = "$1-$2}'
    echo "set term png size 740,560
    set key out top center horizontal
    set xrange [1999.5:2021.5]
    set format y '%.03f'
    set mxtics 5; set mytics 5
    set grid 
    plot '.plt' u 1:2 t 'Albedo' w l lw 2 lc rgb '#0000EE',\
             '' u 1:3 t 'Linear Regression' w l lw 2 lc rgb '#000077'
    " | gnuplot > alb.png

Published by Zoe Phin


43 thoughts on “On Albedo

  1. Great work Zoe. Absolutely vital.

    What’s the source of the annual variation in cloud albedo? In what month is it greatest, in what month is it least? How far back can you get the data? Can you get data by latitude? Its important to know whether the change is over land, over sea or in the high pressure zones or the low pressure zones because pressure changes over time. There will be a correlation.

    Can you select a high pressure zone like that to the west of South America in the Pacific Ocean and chart the change in albedo? There is another high pressure zone in the Atlantic to the east of South America.


    1. Thank you, Erl.

      My data is from 2000/03 to 2021/03. Here are the monthly rankings:

      0.278678 – 8
      0.280476 – 9
      0.285183 – 7
      0.286840 – 3
      0.286942 – 4
      0.290976 – 6
      0.291055 – 5
      0.291453 – 10
      0.292269 – 2
      0.301749 – 1
      0.304523 – 11
      0.306908 – 12

      Greatest albedo in December, Lowest albedo in August. i.e.:
      North Hurricane season has lowest albedo, while Northern Winter has the greatest albedo.

      The rest is a lot of work. You can browse some geographic data here:

      +Add Layer … search for Albedo … select Cloud Albedo.

      I’d like to explore other things before I get back to albedo.


      1. Thanks Zoe. Can you provide the albedo for each year month in the data set? Then I’ll compare it with surface pressure data from https://psl.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl

        The 12.5% reduced albedo in August by comparison with December is partly responsible for the global temperature being 3.5 degrees warmer in July than in January even though solar insulation is 6% weaker in July. I say partly responsible because I’m thinking that insolation falling on the oceans of the southern hemisphere is absorbed to depth and possibly doesn’t much impact sea surface temperature. I expect that the relationship between albedo and surface temperature is not a simple one.

        The albedo is driven by return of heat to the atmosphere above the continents. There is a lot more land in the northern hemisphere. So, there is a decline in cloud cover in the middle of the year.


  2. Bingo. Inverse relationship between the anomaly in global temperature and the anomaly in albedo that appears to explain the variation in the former both on a monthly basis, inter-annually for the entire period since the turn of the century. Would you like the work sheets? erlathapps.com.au


      1. Zoe, it’s an email address take out the ‘at’, put in an @.

        I don’t use a transfer site. Not up with the technology. But its better than snail mail!


        1. Zoe, it takes time. I will. todays post here: https://reality348.wordpress.com/2021/06/04/climate-depends-on-solar-activity-prepare-for-chilly-times-ahead/

          If you see the correlation between your albedo data and global temperature you will be amazed. I owe that to you.

          I’m assuming that when you have a year starting in December in that data, you mean January.

          Today I’m going to a seminar where environmentalists will tell me I shouldn’t burn the bush. I’m just going to have to grin and bear it.


        2. The CERES netcdf file is 03/2000 to 03/2021. That’s what I gave you. I’m not sure what you mean by December/January. The rankings are not calculated, but also in the netcdf file – how convenient.

          Thank you!

          Good luck.


  3. I guess one could say that albedo means that a certain amount of light-rays have a potential to be reflected. We humans manufacture and install windows, that’s what we do – and I guess at an exponential rate. Hence, the potential for light-rays to be reflected should decay exponentially with time (as only a small percentage of light-rays hitting a window will be reflected – correct me if I’m wrong).

    I have been thinking about this. Although tiny compared to the total surface area, it is maybe not insignificant. How many square kilometers of glass-panes do we have worldwide? Every light-ray hitting them would have a fair chance of being reflected had the glass-pane not been there.

    It is estimated that cities worldwide cover 3.5 million square kilometers. Windows are mostly mounted vertically, so laid flat they would cover much of the area of a city.

    Let’s assume one tenth as a careful estimate, i.e. 0.35 million square kilometers of glass panes worlwide. (Including not only buildings bus also cars and so on – even solar panels). Let’s assume twice of that as a bold estimate.

    That would equal an area approximately similar to Germany and Texas respectively. And how much in year 1880??

    Is global warming driven by windows rather than CO2? A funny question asked by silly me , mostly as a joke. But I believe curiosity can never lead to a step backwards in knowledge…

    Any comments? 😅

    Liked by 1 person

    1. Well,
      1st – windows don’t affect atmospheric albedo, only “surface” albedo.
      2nd – do we also manufacture things that absorb radiation better? yes
      3rd – solar panels are absorbant. If we place a Germany’s worth of solar panels – we will definitely have man-made global warming
      4th – air conditioners cool the inside and heat the outside

      Just some quick thoughts


      1. It explains why it got colder after WW2. During the war a lot of windows were broken. Also explains why Bill Gate want’s to spread sun-shading particles in the stratosphere: he feels guilty for being responsible for so many windows…

        Jokes aside. The great salt deserts in South America are now getting turned into open chemical plants….(lithium for car batteries). I believe that they are quite reflective…

        Also, they must be an example of a negative feedback mechanism in the climate system. Warm climate makes the sea evaporate, leaving a highly reflective salt plane, which in turn leads to a cooling mechanism

        Liked by 1 person

    2. Talking of windows and albedo, and realizing that Zoe’s interests lie in effective change in atmospheric albedo, I was wondering whether the annual increase in satellite density might not be a source of effective increase in albedo??


    1. Honestly, I stopped reading after:
      “Convection is physically impossible in the fluid core due to its compression by the weight above and its inability to sustain an adverse temperature gradient.”

      Convection procedes by density. It’s denser as you move towards the core. Weight is irrelevant. My husband’s cigarette smoke convects just fine despite the weight of the air above the smoke.

      The T gradient too is precisely correct to have convection.

      Something bizarre about this paper published in a social sciences journal.

      Thanks for sharing, but I can’t read beyond this blunder.


  4. Read an interesting piece reposted on WUWT, that seemed to indicate albedo reduction might contribute to cooling.
    A fiery past sheds new light on the future of global climate change

    ” Greenhouse gases trap heat and warm the planet’s surface while aerosol particles in the atmosphere from volcanoes, fires and other combustion cool the planet by blocking sunlight or seeding cloud cover. ”


    “By underestimating the cooling effect of smoke particles in the pre-industrial world, climate models might have over-estimated the warming effect of carbon dioxide and other greenhouse gasses in order to account for the observed increases in surface temperatures.”

    Harvard’s School of Engineering were reporting on soot found in Antartica and modeled in computer studies.

    FYI. Don’t know how or if this runs up against your analysis, and the article was short on actual numbers, long on claims (insert my surprised face here).

    Liked by 1 person

    1. Lower albedo, more sunshine reaches the surface. I think the IPCC too mixes albedo with aerosols to confuse the issue. They are separate things, and even if aerosol cooling overwhelms albedo letting in more sunshine, they should still never mix them! but report them separately.


      1. Point. Perhaps reading aerosols as albedo was my error in this instance. I’ll be looking for the distinction in future. Thanks.


  5. Zoe, interesting history of changing albedo. I had not seen that before.

    But I hate to see you use “theoretical” with the CO2 pseudoscience.

    “The theoretical forcing since 2000 would be:
    4.906*ln(420/370) = 0.622 W/m²”

    A “theory” can not violate the laws of physics.

    Liked by 1 person

  6. Zoe,

    Any comment to the so called mathematical proof at WUWT? (Appears as a pingback below). He simply states that the presence of greenhouse gasses makes Mt smaller than Ms. I guess the time interval between absorbing and re-emiting is essential. Not addressed at all.


      1. I have never seen any substantiation on why the radiative balancing-point is moved higher up when the concentation of GH gases goes up. Do you know the explanation for that?


  7. Zoe, have you any idea if any of that change is due to Instrumental drift?
    We know it has bedeviled other satellite data.


    1. I presume that has been accounted. It wouldn’t be embarassing for me if I missed that, but it would be for my source. I think they did their homework.


  8. Zoe, posted this over at Erls, but you may also be interested.
    It is a Chart of Tropics cloud cover vs Global Temps at Climate4You.
    He has a lot of charts and data on Clouds and temperature and is well worth a look, I am not sure how many people are aware of it.


  9. Zoe, Thanks for the albedo data once again. My post that explores the why’s and where-fore’s, the collaterals and the consequences, is now up. I hope it’s meaningful to you.

    To have data that reflects the evolution of cloud cover and its impact on incident solar radiation, and to compare data with the evolution of surface temperature moves me from argument and conjecture towards confidence and documentation. It’s been exciting and liberating.

    Liked by 1 person

    1. Thank you. I’m very happy when people use my work 🙂
      The temperature anomaly matches albedo anomaly quite well. I’m still confused on ocean dynamics. You’re saying there’s some interesting heat belt between North land, South ocean, and peri/aphelion?

      I don’t understand surface pressure as a cause. I think it’s an effect?


      1. If I had your email address I would send this missive addressed to Willie Soon which I hope will go some way in explaining why surface pressure change in the southern hemisphere is causally related to albedo.

        Dear Willie,
        I see the latest paper questioning the modes of variability in climate that contrasts ‘urban plus rural’ with ‘rural’ datasets which is a great approach. There has been no warming in summer in inland Australia since the 1890s. We have just a few sites where the records go back that far but they all agree. I document that here: https://reality348.wordpress.com/2021/02/24/the-absurdity-of-climate-hysteria/ No greenhouse warming from a location where outgoing radiation in summer is disproportionately large. Here, temperature varies according to where the air is coming from, maritime sources versus continental.

        Climate change is driven from the southern hemisphere. This is where systematic change in albedo occurs. Due to the configuration of the landmasses near the equator and the anticlockwise circulation of the air, and the ocean currents, energy acquired in the southern hemisphere is circulated into the northern hemisphere. What I write below relates to Southern Hemisphere dynamics. The acquisition of energy in the southern hemisphere is a cyclical, reversible process that depends on surface pressure in the mid latitudes.

        In the last week I obtained Ceres data for variability in albedo from Zoe Phin. Due to the ubiquity of cloud 90% of that albedo is due to cloud. The dataset is worthy of very close examination to discern the nature of the variability it reveals. Surprisingly the relationship with global surface temperature indicates that the variability in albedo is sufficient to explain the variation in surface temperature in the mid latitudes of the southern hemisphere. In the tropics variability is related to ENSO, that is a red herring because its variability is due to upwelling phenomena that is directly related to surface pressure in the south east of the Pacific Ocean under the control of the Antarctic trough and the Aleutian Low.

        Polewards of 40 degrees of latitude insolation is less than radiation and in the absence of variation in temperature due to ocean currents, surface temperature is less than air temperature. Here near surface air and sea temperature depends on how much extremely cold air is coming from high latitudes in relation to the flow of tepidly warm air from the mid latitudes. As the area that is affected by Polar Cyclones (extratropical cyclones) has expanded in the southern hemisphere, particularly after 1978, the variability in temperature in these latitudes has gone from nought to massive and these latitudes have cooled. High latitudes are a sink for energy. If energy goes there it disappears for ever. Gone to radiation.

        The mid latitudes of the southern hemisphere is where high pressure cells lie over the Ocean. Here surface temperature varies with surface pressure. These cells of descending air are relatively cloud free. As surface pressure increases an atmospheric window opens to admit sunlight that probably varies directly with the surface area affected.

        The warmth that accumulates in the tropics is circulated into the northern hemisphere. Here, all months show warming but with more in the last half of the year which is due to ENSO warming from April onwards.

        The southern hemisphere has not warmed in December when solar irradiance is 6% greater than in July and global albedo peaks….. due to the cooling of the landmasses in the northern hemisphere in winter and what that does to condensation phenomena that builds cloud cover.

        I explain the dynamics here: https://reality348.wordpress.com/2021/06/14/the-linkage-between-cloud-cover-surface-pressure-and-temperature

        The climate problem requires a multidisciplinary approach. That’s where an amateur like myself who has spent 20 years looking at reanalysis data can make a contribution. The geography and history of the atmosphere is written in reanalysis data. It is only via an understanding of the modes of change that occur in the stratosphere, and in high latitudes in winter, that we can understand what’s happening in the troposphere.

        Best regards,
        Erl Happ

        Liked by 1 person

  10. Zoe, This bit I added as a postscript.

    Albedo in the northern hemisphere is driven by the heating of the atmosphere by the landmasses in summer and the cooling in winter. Its relatively invariable because this relates to simply to the surface area involved, apart for one notable exception and that is the incidence of the monsoons which Chinese researchers link to variability in the Antarctic. In East Asia, its the difference in surface pressure between the Chilean High and the Maritime continent (also driving ENSO) that will be important. This drives the Trade winds. After the month of May that depends on the surface pressure in the Antarctic Trough. At that time of the year there is no influence from the Arctic.

    Without an understanding of the modes of variability in the atmosphere (Annular Modes) and how this relates to ionization phenomena in the atmosphere, and the interaction with the Interplanetary magnetic field we are not going to be able to cut the mustard and stop the stupidity.


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