There is nothing new about global warming deniers. In the 19th century a growing number of scientists accepted the evidence that carbon dioxide in the atmosphere could act like a green house - trapping heat. However there were other scientists who denied the evidence. By the twentieth century the deniers were in the minority. The following dataset from NOAA has several decades worth of carbon dioxide measurements. The increase is clear to see.
During this time we have seen new record high temperatures, bigger storms, melting ice and rising sea levels.
But despite the evidence Trump is a denier, his priorities are the economy and jobs and he believes it is better for the U.S. to invest in old finite fuel sources like coal rather than investing in limitless new technologies. It is possible that while other countries solve their energy needs with new technologies and innovation the U.S. will still be sending men down holes in the ground to dig out dirty black coal. The following tweet from Donald makes his attitude clear.
Prior to this he had blamed it all on the Chinese.
The Chinese certainly did their part in contributing to the increased carbon dioxide levels but it is not a hoax manufactured by them.