Are humans contributing only 3% of CO2 in the atmosphere?

Originally posted by jantimot ↑

"At which point?"

You might at least view your own link. He clearly hasn't any depth in his knowledge, or else he is just an actor reading a script. And if you didn't notice the error at 4.21, I suggest you are probably missing a lot from many other articles.

So it isn't surprising that you've missed a lot of other data in your simplistic assertions. For instance, CO2 levels rose 50% from their all time lows of 180ppm 18,000 years ago by the end of the ice age:

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http://www.geocraft.com/WVFossils/last_50k_yrs.html

The scary thing from that chart is that the earth was only 20-30ppm of CO2 from a potential total wipeout of plant life on land:

http://onlinelibrary.wiley.com/stor...co&s=cb7da81d4a024d268ae101be91f6caa6c3a1efa0

Fortunately a completely non-manmade event occurred resulting in higher temperatures, which resulted in increased CO2 levels. From that article you can see that optimum levels for photosynthesis occur at the 500ppm mark.

Yes, I meant "we the planet" rather than we as humans - but the premise still applies - CO2 levels have been a minimum of 20 times hat they are today, and the earth, instead of frying, was abundant with life.

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"He clearly hasn't any depth in his knowledge"

Right, so it was a pointless nitpick and you refuse to tackle the actual argument about the denialist myth. Thought as much!

"For instance, CO2 levels rose 50% from their all time lows of 180ppm 18,000 years ago by the end of the ice age"

And? That doesn't contradict anything I've previuously said. Was there a point here or is this just some feeble red herring/nitpick attempt?

"From that article you can see that optimum levels for photosynthesis occur at the 500ppm mark."

And? We don't photosynthesise. We are humans. We evolved under conditions of ~180-300 ppm C02.

"Yes, I meant "we the planet" rather than we as humans - but the premise still applies - CO2 levels have been a minimum of 20 times hat they are today, and the earth, instead of frying, was abundant with life."

I thought as much. You do realise it's rather irrelevant to us humans if simpler fauna managed to thrive in higher C02 concentrations? We aren't them. Again, we evolved under conditions of ~200-300 ppm C02, so we're heading into uncharted waters now. Of course this little fact needn't concern you as much as the unthinkable horror of having to concede a silly argument in your precious culture war.

Very disappointing that you can't rebut any of the substantive arguments made in the video, and resort to feeble references to vague "errors" and ad hominems about "actors" (the author is actually a Geologist by training).