Significance of solar constant?
Question:
Answer:
The solar constant is the change in output of the sun over time. It has been steadily increasing over the last 4 billion years.
The significance of the constant is pretty big when considering global climate change. As the solar constant increases, so do the chances for a runaway greenhouse effect (which is inevitable - eventually the sun will turn the Earth into something akin to Venus (and women will then be happy 'cause that's where they are from), but this is unlikely to happen for a few hundred million years at least). The real threat is that, in the past, the increased radiation of the sun has been offset by a continual decrease in volcanic activity and atmospheric CO[2] levels - this is known as a long-term negative feedback. But if the CO[2] levels return to what they were in Precambrian times (we would have to evaporite all the limestone and dissolve all sedimentary rock on the planet to do this - effectively increasing CO[2] concentration in the atmosphere about 1600x), then the world would probably never return to the state that it is today because the solar constant is so much higher (it was about 75% what it is today about 4 billion years ago).
Not to worry - we will run out of fossil fuels and probably be extinct long before CO[2] levels even have a chance of becoming that high. Even at current rates of CO[2] release, we can only increase atmospheric CO[2] to about 4x pre-industrial levels. Just know that the solar constant is transient and the sun is getting hotter.
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