A tiny minority of people claim that the science of climate change is wrong and that if any change is happening, it is not the result of human activity. Most are not scientists and even fewer are qualified in climate science. Importantly, most do not publish their opinions in scientific journals, where their ideas can be checked by others through the peer review process. Instead many "climate sceptics" promote their ideas through television and newspapers, where the only checking done is by journalists.
Journalists are usually not scientists
Journalists are not climate science experts either and are often unable to properly check ideas presented to them as "science". Most journalists have little or no training in science and few know whether the person they are talking to genuinely understands the subject. Rather, journalists are trained to look for two sides to every story. So even if 99% of expert scientists say that climate change is happening, many journalists will give equal attention to the 1% of non-expert, non-scientist sceptics who claim that it is not happening.
As a result, this tiny handful of climate sceptics get a lot of attention and publicity, even though the vast majority of professional climate scientists disagree with them.