[throwaway010718]

Somewhat off topic comment, but in 2003, Bill Bryson's book "History of Everything" states that anthropogenic CO2 output is 7billion metric tons per year where natural CO2 output is 200 billion metric tons a year (mostly volcanoes IIRC)[0]. It left me with the impression, that an additional 3% a year is small and we have time before this becomes a crisis. For the record, Scientific American calls Bill Bryson "A Champion of Science".

Then when climate change appeared to accelerate, I assumed that it must because we are removing our carbon sinks and that deforestation is likely the more dominant cause than our +3% additional emissions.

Earlier this week, I revisited the above figure and according to Scientific American: "the world’s volcanoes, both on land and undersea, generate about 200 million tons of carbon dioxide (CO2) annually, while our automotive and industrial activities cause some 24 billion tons of CO2 emissions every year worldwide." [1]

At 3% I can see how a climate change skeptic might feel this issue is alarmist. But if it is 12,000% I don't see how anyone could honestly be skeptical that global warming isn't being caused by humans.

It is mind boggling that two authoritative sources could differ by 3000X. Any clarifying comments are appreciated.

[0] https://books.google.com/books?id=_CWlKRYLbIwC&pg=PA268&lpg=... https://www.scientificamerican.com/article/earthtalks-volcan... [1] https://www.scientificamerican.com/article/earthtalks-volcan...

[EForEndeavour]

Wait, so in his book, Bill Bryson casually overstated the natural CO2 output by a factor of a thousand? I have to wonder how such a massive mistake got through the editing process. It's not even a simple typo, it's the lynchpin of Bryson's argument that humans contribute a negligible fraction of total atmospheric CO2.

[mediumdeviation]

Comparing man made emissions against natural is somewhat misleading. The damage caused by carbon emissions is related to its atmospheric concentration, which _is_ increasing at an alarming rate. It doesn't matter if man-made emissions is 3% or 300% of natural rate, as long as the net emission, as a percentage of the carbon already in the system, is large. Carbon naturally exists in a cycle, so natural emissions is always roughly in equivalent to absorption.

[stevenwoo]

The Sci-Am Q&A is not dated but this is and also provides enough information to look at the raw data if one should choose to, it also provides a pretty wide range for volcano output but less than 1 billion tons a year for the last 250 years. https://www.climate.gov/news-features/climate-qa/which-emits...

[phs318u]

Didn’t read the links but the numbers in your comment differ by 3x (7 billion vs 24 billion). Unless I’m misreading something?

[throwaway010718]

The human mind is susceptible to priming. When I read the SciAm article earlier this week I was sure I read "200 Billion" since that is what I was expecting. But upon reading the conclusion that number made no sense and I swear the B magically became an M.

[verelo]

One is million vs billion.

[phs318u]

Thanks. I was looking at the wrong number. The scale difference is in the "200" number.