So what? What is the significance of this?
Seriously. I keep hearing this and I don't understand what the significance of this is. Think about it.
1. There was 5 times the amount of CO2 during the Jurrasic era than there is now.
2. The Jurassic era was 145 million years ago.
3. Homo Sapiens emerged about 200,000 years ago. That means for 144.8 million years, there were no humans.
4. In the 144.8 million years, the level of CO2 dropped to whatever it was 200,000 years ago, but presumably this is reasonably comparable to what we had in 1900.
5. CO2 was high and there were no humans. CO2 drops and Humans evolve. CO2 begins to increase again with humans around.
So what is the significance of CO2 levels in the Jurrassic era? All it tells us is that over a period of at most 145 million years, CO2 levels dropped significantly. The 100 years since 1900 represents 0.00139% of 145 million years. Is the change since 1900 to scale with the change from Jurassic era to 1900?
If the scales are equal, it's probably natural.
So let's do the math.
The claim is that 5 times the CO2 existed in the Jurassic era, so:
Current ppm: ~370 in 2000, extrapolated from 1900 that means it's about 382.
1900 ppm: ~290
Jurassic era: 5 times 382 = 1910
So, reduction per year over 144,999,885 years = 84.81675% decrease, or on a per-year scale about 0.0000005849% decrease per year from the Jurassic period to 1900.
Increase of 28.5862% from 1900 to today, on a per-year scale is 0.23988% per year.
Does a rate of change of 0.0000005849% equal 0.23988%? NO!
In fact,
the rate of change from 1900 to today is 410,090.93 times greater than over the time period from the Jurassic Era.
So, why is this significant? Because we don't know what is going to happen next. We can predict forwards what will happen to the climate and how humans will adapt to it. But that's why it is important. Human's are required to adapt to whatever changing conditions we come across and if there is change in the global climate (which there has been since 1900) it will almost definitely result in the mass death of billions of humans in the future.
That is a bad thing.