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The Yale Project on Climate Change Communications asked Americans, “If you had the opportunity to talk to an expert on global warming, which of the following questions would you like to ask?”

The top question, said their report, “Global Warming’s Six Americas in May 2011,” is “How do you know that global warming is caused mostly by human activities, not natural changes in the environment?”

So this is a question that all climate hawks should be able to answer, and the figures/charts in this post are ones that you can refer to. I just used this post myself yesterday during a radio interview.

Given the popularity of my recent “Illustrated Guide to the Science of Global Warming Impacts,” which collected and summarized dozens of posts covering some 50 scientific articles, I thought I would occasionally repost updated versions of other important pieces and reviews.

Last year, physicist John Cook, who runs the must-read website Skeptical Science, published “The Scientific Guide to Global Warming Skepticism.” It’s a good introduction to global warming science and skepticism.

He sent me the eight figures of the “human fingerprints on climate change,” which I repost below.

The clever deniers these days don’t deny the painfully obvious reality that the planet is warming or that climate is changing — they simply deny that humans are a major cause.

But in fact there is an overabundance of evidence that humans are warming the planet and changing the climate, so much so that the U.S. National Academy of Sciences labels as “settled facts” that “the Earth system is warming and that much of this warming is very likely due to human activities.”

Here are key fingerprint figures:

I wouldn’t recommend referring to all seven when asked the question. Just pick two or three to familiarize yourself with, and then give people this link.

For those who want to dive in deeper, here is a post that contains links to one scientific study for each of the seven fingerprints, plus three more.