<p>I guess my first question is where you got Mauna Loa CO2 data from 1900, since my textbook lists data starting circa 1960, hence I can’t say anything about your claims from 1900-1940 and 1940-1960’s, if you could post a link that would be helpful. </p>
<p>The “global mean temperature” is a bad indicator. Anything that plots an average temperature over the entire earth is very vague, but if you have a link I’ll take a look. I think I mentioned that before somewhere. But even with that bad data, it makes sense that temperature levels don’t vary widely (but you should note that .4 degrees is still significant, if it is truly representative of the actual temperatures). The global mean would average hot summers in Death Valley and cold winters in the antartic. But as I said, global warming doesn’t just mean “heating”. It leads to more extreme seasons, so that summers get hotter, and winters get colder. I don’t know the proportionality, but because of that, averaging over the world wouldn’t, therefore, lead to spectacularly varying temperatures.</p>
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<p>Again, a link would be nice, but I never said (nor do scientists) that greenhouse gas emissions was a straightforward tracking. There are many variables. El Nino, volcanoes, earthquakes, are some natural ones that come to mind. Also, it isn’t like human CO2 emissions just “turned on”. The U.S./Britain industrial revolutions started circa 1800, with India and China (4 largest contributers) staggered later on, increasing output at varying rates. </p>
<p>I also never said humans were the sole source of global warming, but when anyone says people play no part, it’s ridiculous and mind-boggling.</p>
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