12/12. There several I had to think about.
Same here but only one question made me think, carbon comes from life and life comes from the sun but I wasn't sure
they thought that deep; an old fogey I recall the Sinclair Oil Commercials and knew that dinosaurs played a very minor part of fossil fuel creation so had to go to the source.; was correct but all of the answers were possible too some extent, even Uranium adds to the earth's ability to generate some heat outside of the sun; the Hawaiian chain, the older Aleutian chian, Yellowstone, ...
The PPM was easy for me roughly 300 in the 19th century and approaching 400 for yearly average in the 2015 (up almost 3 PPM) and February we passed 400 which was the estimated highest level of C02 for Homo Sapiens and perhaps entire
Homo genus. The point is we have been in a global cooling environment since the beginning of the Miocene some 20 million years ago.
A good read, though I question their absolute numbers was in Scientific American
http://www.scientificamerican.com/article/co2-levels-for-february-eclipsed-prehistoric-highs/ Whether CO2 stays in the atmosphere 5, 10, 20, or more years it doesn't stay long and if we cut the cord on fossil fuel we would be cooling down; currently the best estimate is several generations in the future before we see a trend reversal even if the commitments made at Paris all go into effect, all nations adhere to their commitments and something disastrous doesn't happen before they can work.
When that cooling process begins is what is undermined; predicating where levels will rise to before a major trigger occurs is what worries me; we are at the limit were major things happened 150,000 and 300,000 years ago and now entering uncharted territory for our species. We still can slow down increases, keep them to a couple more degrees rise (
Fahrenheit) or Celsius degree if we don't exceed 450 PPM but something catastrophic for mankind may happen in the next few centuries; hope I'm moldering in the grave before it does.