A while ago, I read the 6th IPCC report. (Nope – not the whole thing! Just key issues.) While I read it, I thought this is not really understandable to an average person, who does not have knowledge of natural sciences and the wording that comes with it. In my opinion, this is not just only the case with this report, but also with so many other topics regarding climate sciences. And yet, this topic matters to all of us.
Today, I want to explain the most important process of climate science, which is the greenhouse effect.
The greenhouse-effect is the reason why we are able to live on earth, since it rules the global temperature. On average, the planet has a temperature of +15°C, at the surface. Without greenhouse gases, this temperature is estimated at -18°C (greenpeace.de).
Let´s start with some definitions so that you know, what I am speaking of greenhouse-gases are gases that cause the greenhouse effect. They exist in the atmosphere in very small amounts. The atmosphere is the shield of air around our planet, consisting of different gases like nitrogen (78%), oxygen (21%) and in small amounts: argon, carbon dioxide, water vapor, methane and ozone.
Not to be confused: greenhouse gases are not the same as the atmosphere, but a part of it. Particularly they consist of: Water vapor (H2O), carbondioxide (CO2), ozon (O3), methane (CH4) and nitrous oxide (N2O).
Water vapor is the major component of the greenhouse gases. Carbondioxide is produced through countless combustion processes of human but also natural origin.
Methane is emitted e.g. through melting of permafrost (frozen soils in the polar and subpolar climate in the global north, which are a profound source of methane and carbondioxide), destruction and cultivation of moores and livestock husbandry of cows, because they are emitting them through digestion. Methane is about 30 times more climate effective that carbondioxide. This means, that one part of methane is as effective (as a greenhouse gas) 30 parts of carbondioxide. In other words, methane is worse for global warming than carbondioxide. The same happens to be true for nitrous oxide. Nitrous oxide is emitted by soils, fertilizers and incineration of biomass.
Now, that you know what the greenhouse gases consists of, let us continue with how the phenomenon works:
It works like a shield of protection, which filters a part of the solar radiation into the earth’s atmosphere and reflects another part of the solar radiation back into space. This shield works both ways. The other way around, the greenhouse gases keep the earth´s own radiation (thermal radiation, causing warm temperatures) inside the atmosphere.
To sum it up, the greenhouse gases are preventing the thermal radiation of the earth to emit into space and they filter the solar radiation which leads to a positive (warm) global temperature. Hence, the earth becomes habitable.
Currently, the greenhouse gases are negatively-associated due to climate crisis. Why the negative association?
Since the industrialization, the amounts of greenhouse gases, especially of carbondioxide and methane are increasing fast. Which means, that there are more greenhouse gases in the atmosphere and the earths own radiation is kept inside the atmosphere instead of emitting a part into space. Which leads to an increase in temperature – aka global warming.
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