bripat9643
Diamond Member
- Apr 1, 2011
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It was within 1%. Nuclear physics shows that temperarture of the sun hasn't changed much over the last one billion years.
1 Billion years ago the Sun was 35% cooler abouts.
You say just 1%? Hardly.
And 1% is 13watts.
Which is significant.
4 watts is what we are worried about. Get it?
So 1% solar irradiance shift would be DISASTROUS.
We aren't talking about 1 billion years ago. CO2 was at 4000 ppm 150 million years ago - 10 times what it is now. I also question your claim that it was 30% dimmer 1 billion years ago. That would mean the sun was dark 3.5 billion years ago. The sun is 4.5 billion years old, so I find that difficult to believe. Life on earth is about 4 billion years old, and that requires liquid water. So the sun produced enough energy 4.0 billion years ago to keep the temperature of the earth about the same as it is now.
I can't find a chart of the irradiance of the sun over geologic time, so I am unable to verify your claims. Unless you provide such a chart, I can safely assume they are false
150 million year ago the Sun was about ~20%-15% cooler than it is today.
So what's your point?
250ppm CO2 = about 4watts/m^2.
20% of 1360watts/m^2 is 272watts/m^2 offset.
So that'd require 50x Co2 alone to offset the temperature lost by the Sun.
Not able to answer the discrepancy is why there is a "faint young sun paradox".
Faint young Sun paradox - Wikipedia
Faint young Sun paradox - Wikipedia
Early in Earth's history, the Sun's output would have been only 70 percent as intense as it is during the modern epoch.That means it was 30% less 4.0 billion years ago when life began and we therefor know that liquid water existed on the Earth's surface. To get the difference 150 million years ago, take 150/40000 = 3% less bright 150 million years ago than it is now.
OK, 3% of 1360 watts = 40.8 watts.
Which is 10x as much CO2 as 250ppm or 2,500ppm to OFFSET that much reduced Solar output.
GET IT?
You just proved me right.
The problem with that theory is that CO2 goes to almost zero earlier when solar radiation is even less. Look at the chart I posted.