Our planet is warming as a direct consequence of us increasing CO2 concentrations in the atmosphere by burning fossil fuels. This is what the laws of physics and chemistry tell us should happen. But more than that, scientists have experimentally shown that this is the case. This isn't some mad theory or the prediction of a model. It is what we experimentally observe to be happening.
Anyone telling you our planet isn't warming due to our burning of fossil fuels is a liar. They are evidentially, mathematically, experimentally, physically, chemically, spectroscopically, etc wrong - or in other words pretty much as wrong as you can get. We should ignore those people, in the same way I ignore anyone questioning evolution or questioning whether the earth is round.
The main issue is some people from an older generation who are worried that dealing with climate change will hit them in their wallets. They're happy to screw over my generation and the one in our primary schools ...