It took millennia for humans to realize that we were standing on a ball of dirt and water. A very large one, but a globe nevertheless. I'm certain that only a few humans over that time figured it out on their own. It couldn't have been too hard to generalize from the moon, an obvious large ball of dirt out there in space, to what we are standing on. But for a large portion of humanity it wasn't until the 15th Century that they were able to get their head around the idea that Earth was a globe.
But then seeing that our Earth circled the Sun rather than the other way around was even more difficult. The significant discovery of Copernicus was published posthumously and it was another 100 years before heliocentrism was generally accepted.
And we might feel more smug about how we see the world today, but amazingly perhaps 95% of people (I'm afraid that it might be more like 99%) think gravity is an attractive force even though Einstein disproved that 100 years ago. Anyone experimenting by, for example, jumping off of a curb, is convinced that what brings them down to the ground is the attractive force of Earth's gravity pulling them down. They hold a rock out and let it go, and the rock plunges to the earth -- gravity in action. But Einstein in his General Theory of Relativity has shown us that in fact gravity is not an attractive force, but is a warping of 4-dimensional space: in effect the rock is sliding down a slope created by the mass of Earth distorting space.
When it comes to gravity, most people are in the same place as people in the 17th Century were about the Earth rotating around the Sun. They may have come to understand some things about the physical world around them in defiance of what their senses tell them, but there is still a ways to go.
Scientists, physicists, biologists, etc., have more complete pictures of the world around them, but among people who aren't scientists, there are few who really are able to comprehend reality. For most people their understanding of the world around them is mythological, for example, that the gravitational force of Earth is pulling them to the ground.
The primary problem people have in dispelling mythologies is overcoming what the senses tell them about the world. It is actually a lot easier to think about the sun rotating about the Earth than vice versa. And a lot easier to think that the Earth is pulling them to the ground. And, I argue, it is the same with global warming. Scientists are developing strong evidence of global warming, but it is too hard for our senses to see that it is happening. No amount of evidence will dispel the mythology the deniers of global warming have constructed in their heads because the evidence is too abstract, like the evidence that gravity is not attractive but due to warping of space. Or a violation of our senses that sees the Sun going around the Earth.
But the problem is, it's okay for people to fail to understand gravity, or even that the Earth rotates around the Sun, but it's not okay for people to fail to understand global warming. The consequences of the failure is dire. Only a few people need to overcome the mythology of gravity, space engineers mainly, but it is going to take a lot of people to sweep aside the mythology preventing them from seeing global warming because a large consensus is going to be required to take the actions necessary to avoid the dire consequences.