What brings on an ice age? What brings the planet Earth out of an ice age? Why do we have evidence of massive climate shifts long before human civilization? How can we separate man made in puts from natural inputs? If you ask these question, eventually someone will call you a “climate denier” and accuse you of being a bad person.
But, because these are rather important questions to answer, people who truly believe in anthropogenic climate change create charts like this. This chart is put together to summarize six research papers that demonstrate that the vast percentage of “global warming” in the past few decades is caused by human activity in an attempt to build the consensus argument for anthopogenic climate change.
Now I’m not saying that the chart is wrong, but only the last two colors labeled HK11 and G12 are anywhere closer to being potentially accurate because they are the only two that seem to add up to an actual 100%. All the rest are significantly over, for example T00 says that human factors account for positive 175% of observed warming, and natural factors less than negative 30% during the same time period. Since the actual change in temperature is a real number, the obvious conclusion is that we aren’t talking about 100% of any observed numbers here.
And statistics are an easy way to mislead. First off, percentages are a dimensionless value, and without normalizing all these studies to the same standard, you start comparing dimensionless values against other dimensionless values without regard to reality. Is the warming 1 C or 1 F over the time period? You can’t tell from the graph, only that 4 out of 6 studies thing that absent “human influences” it would have cooled, and 2 out of 6 think that absent “human influences” it would have warmed.
But which is it really? Would the planet have cooled by 30% or warmed by 20%? Honestly none of the papers can agree on that point at all, so we are only left with six papers that expound the green orthodoxy view that human activity is the number one climate driver. But it all looks rather impressive to someone who doesn’t really understand statistics.
Of course none of these problems are really problems, after all who cares about actually understanding how much climate change is natural when we can get a bunch of people to agree that it’s closer to 100% (with ranges from 90% to 160%, never mind the uncertainty or the man behind the curtain).
Why bother with any of that? It would require people to actually talk about water vapor and carbon dioxide, and get into some very contentious “feedback cycles” that are needed to amplify very small changes in atmosphere composition into very large and scary temperature readings. And if you can’t do that, use percentages. Cause 160% of a very small number is still 160% and therefore scary.