of that number how much was put there by man's activities
About a third. As CD said.
most scientists agree that the percentage of man made co2 ito total co2 in our atmosphere is less then 4%
meaning 96% is nonman made
doesnt it seem like we are getting excited over a very small amout percentage wise made by man
why is the 4% determined to be the main cause of climate change
This is incorrect. The fact is that some carbon in our atmosphere is good and normal, and our planet has a carbon cycle that for the last milion years has held carbon between about 250 and 300 ppm. The carbon cycle means that there are plenty of natural CO2 emissions on the planet, which is where the 4% comes from. And the planet is capable of pulling the same amount of carbon out of the air each year as naturally emit. It's in balance.
Based on some research I've done related to this 4% claim, it's believed that on an annual basis, 96-97% of the CO2 emitted is from natural sources, and only 3-4% is man-made. Which is a different claim than only 4% being due to man.
But the issue is that the planet doesn't have any way to handle that extra 3-4%, because it's in excess to the natural carbon cycle's capacity to pull out of the air. Hence, the concentration in the atmosphere is accumulating based on the extra 3-4% that is emitted every year.
So if you ask about the rise from 280-410 ppm over the industrial era, I would state that the rise is almost entirely, if not entirely, caused by humans. Even if it it was only 3-4% of emissions per year, that can add up QUITE a bit of accumulation over the span of 150+ years.
