Using PET reflectors to Cool Earth

PET bottles are made by the billions each year, to be precise, 583,3 billion, that is 583.300.000.000 bottles which is an insane number, given the world population is only ~7 Billion people (so maybe wrong?)!

Let’s say its half that, so 300 billion bottles. We can make something else from that PET plastic, namely reflective sheets. If we assume the same thickness we can make the same surface area as those bottles. Taking one bottle as 15 cm diameter, 40 cm high, this is .32 m2 of surface, like a common sidewalk pavement tile. If we multiply this we find we have 96.000 square kilometers of surface.

PET based reflector from Yongtek

We can make PET 94% reflective. At the equator the Sun power is 1000 Watt per m2, so this material reflects back 94% of it, which is 940 Watt/m2. For the 96.000 square kilometers this is 9,024 x 10 with 13 zeros, or or 90,24 TeraJoule of energy.

The world recieves about 3 400 000 EtaJoule per year, an EtaJoule is 1 with 18 zeros, so 6 more than a TeraJoule. This really is a lot, so the energy send back to space by the reflector may not do much, but it may compensate the loss of sea ice, and it may be used in ways that amplifies its own effect, for instance in mountains, where the colder air then causes snowfall which then cause more white surface to form.

If you reflect 94% of the light back in a region, it will seem like the sun is 94% dimmer there. It will become cold, and rain will fall and probably freeze, I yet have to get a good model to simulate those effects. The wind over the area will also cool down.

If the PET is used on the ocean, preferbly a quiet part of it, then the albedo gain will be quite pronounced. Land Albedo (reflectance) is ~30%, but ocean albedo is near Zero! The water will still be able to radiate heat because the PET will take on the same temperature and will be quite thin. So floating PET on the ocean can help cool it, and the air at the same time.

This kind of idea seems idiotic, but if you consider you can keep oceans alive, seacreatues alive, cool the atmosphere, prevent violent storms (because there will be no evaporation) the advantages start to add up.

Maybe we can stop using PET bottles and cool regions enough so we dont need bottled water anymore!


Increasing Local Albedo

One of my quests at the moment is to get an accurate idea of what local albedo changes will do to temperature. This is to make it clear for people what they can do to lower temperatures, which can be life saving, not only human lifes but of all lives. I’m working with a climate expert to find answers. The scale we work on now is still crude : 9km x 9km.

A random location in Pakistan

The above shows a region in Pakistan, with farmland next to dry uncultivated land. Possibly because of an underground aquifer or river, but also because of temperature differences. The albedo of green land and sand is similar about 30%, just in a different spectral regions. The model shows the temperature distribution under ‘normal’ conditions.

Normal temperatures

This image shows the sandy area is actually cooler than the agricultural area. This can be because the green shrub and black soil absorp more heat. If you increase the albedo of the entire area you get this result..

Enhanced Albedo Temperatures

This is the area with higher albedo 80%. The agricultual land is much cooler, it seems almost 100 degrees Fahrenheit! But we effectively turned the whole area in a polar ice region. I am working on a more detailed model. What would happen if you add alternating rows of white soil (calcium) between vegetation? If you know good models let me know.

A good question is also : If you increase albedo and the temperatures drop, does that mean it will start to rain? To be continued..


Albedo Enhancement

Make Earth Shine

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Making Higly Reflective Paint

Spaceflakes to shield Earth

Increasing Local Albedo Part I

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Quick Q & A

  • What is Albedo?
    • It is the ability of a surface to reflect sunlight. You can call it Earthshine.
  • What happens to the reflected sunlight?
    • It leaves the atmosphere into space
  • Why is this important?
    • It determines how hot and cold it can get on Earth
  • Can we change Albedo?
    • Yes we can, because it depends on what is on the ground or your roof or what floats in the oceans
  • Can it have effect on climate change?
    • Yes, we can almost reverse the temperature increase and at least reduce it
  • Why is it important that temperatures stay lower
    • Because plants that capture CO2 can not grow when it gets too hot, so we can buy time by increasing Albedo

Albedo increase is one of the three main actions to fight climate change

CO2 emission reduction and recapture are not going to cool Earth quick enough, so welcome this is a website dedicated to the enhancement of global albedo. Albedo is the reflective power of a Earth. The amount of radiation a Earth’s surface sends back to where it came from differs quite a lot from place to place. White snow has the highest Albedo and black soil and open water the lowest. This matters because it is by absorbing radiation from the Sun that the Earth warms up. The more Earth reflects, the cooler it will stay.

Albedo is the reflective property of the Earth surface. If it is highly reflective the heat does not stay on Earth but leaves into space, cooling the surface.

The albedo value is expressed in a number that is 1 when all light is reflected and 0 when all light is absorbed. below is a list of materials and their albedo.

More on Calculating Albedo Effect

Corrugated Roof0.1-0.15
Cirrus cloud0.2
Thunder cloud (cumulonimbus)0.8
Altostratus cloud0.35
Stratus cloud0.4
Polished aluminium0.99
Desert sand0.4
white gypsum0.85
Special polymer paint0.98
Special foams0.75
Different materials have different albedo. Some specialized materials have been developed. Silver mirrors are most reflective.

Now that the CO2 concentration is rising, the atmosphere is not letting as much heat radiate out to space as it used to, and this is changing climate. By enhancing Albedo we can help Earth shed the heat it is accumulating. This is very important for life, especially of plants, that we need to capture back the CO2.

The importance of white surfaces for cooling has been known for many years..

If we work around the world to increase Albedo where we are we can regain control over our environment, and cool it down to where it can both produce food and capture CO2. This website is to help you find the best way where you are. There are new materials with 95%+ reflectance, and we hope we can make those widely available or instruct you how to maximize the effectiveness of the materials you use. The important thing is to start looking for opportunities to use white surfaces, because they also save a lot of aircondioning emissions.

“An experiment conducted in western Athens found that brightening of asphalt and concrete pavements reduced ambient temperature by 7.5 degrees and 6.1 degrees Celsius respectively.” (link)

A NASA analysis of the albedo of Earth without clouds. Its 0.3 on average. Oceans have really low albedo, and thus there is massive potential to reduce warming.

“A recent study in Los Angeles County analyzed the energy savings of modestly increasing roof albedo, finding that this could produce savings from reduced energy use of 23% to 40%, making cool roofs a financially attractive option.”

Source The performances show that the bilayer paint design can achieve both color and efficient radiative cooling in a simple, inexpensive, and scalable manner.

How to calculate Albedo

Patent for highly reflective polymer 1

Patent for highly reflective polymer 2

Chapter on Albedo Enhancement Techniques