Just to clarify,
"global warming" in the sense of climate change and rising temperatures is very much real - it's human's share in that effect which is actually minimal.
"Global warming" in the sense of
"evil men came, they built factories, polluted the world and now we're all getting cooked alive" is a huge stretch.
For example, volcanic activity consistently created greenhouse gases over the period of millions of years - we've been creating greenhouse gases for a handful of years in comparison. We mostly contributed to ozone depletion due to increased CFC gases emission which has been minimized ages ago and even then the supposed
"hole" we've created in the ozone layer turns out to be somewhat a natural occurance related to the ozone cycle. The hole
"opens" and
"closes" every year as UV light hits O3
(ozone) molecules, freeing O and O2 molecules and later, once those build up, it causes a reversed reaction creating O3,
"shrinking" back down.
The problem with this is that it gradually becomes larger, causing more and more UV rays to be trapped on
"the wrong side" of the ozone layer, increasing Earth's temperature in the process. It's a widely-accepted consensus that this is a natural process and the Earth has been
"through" such climate changes a number of times in the past. We contribute towards it, but we are hardly the sole cause of it.