What is albedo?
Reflectance or albedo (”whiteness”) is the ability of an surface to reflect incident short wavelength radiation (i.e.light). It describes the radiation coming into contact with that item, and the ratio of the reflected short wave radiation. With albedo, one can study how much our planet absorbs energy and warmth. This is important information when studying the climate change or global warming because the very root reason of the warming is that due to greenhouse affect, the solar radiation can’t bounce back to space as it used to. Thus, the cause of the climate change is radiation and greenhouse gases.
Albedo is expressed either as a decimal fraction or a percentage. A value of 0 indicates that the surface absorbs all solar radiation (e.g black), and a value of 1 represents total reflectivity (e.g white). To get a bodily experience of albedo, one can wear light and then dark clothing on a sunny day.
Snow has albedo value 0,9 and charcoal 0,04. Earth’s average albedo value is 0,3. The radiation is reflected from ground, water, clouds and atmosphere.
The change in albedo can be defined also in joules which makes it easier to understand. The joules can be then calculated for example in gasoline litres. One litre of gasoline is 42,4 megajoules.
What is geoengineering?
Geoengineering is the intentional, large-scale technological manipulation of the Earth’s systems, often discussed as a techno-fix for combating climate change. Climate engineering technologies can be divided into areas of:
1. Solar Radiation Management (how much short wave radiation is incoming)
2. Earth Radiation Management (how much long wave radiation is outgoing)
3. Greenhouse Gas Removal
4. Weather Modification.
Graphic via Guardian, Giulio Frigieri/Observer.