Leading Republican presidential candidate Mitt Romney is accused of changing his colors again, this time on one of the most sensitive global issues, climate change and human impact.

His first position was admitting human impact on climate change and supporting the reduction of emissions of greenhouse gasses.

Then the former governor of Massachusetts declared he was not sure if human activity contributed to global warming or how much.

Again, this stand changed when he declared that people do not know the cause of climate change on this planet and spending a lot of money is not the proper course of action, CBS News reported.

U.S. media have noted that Romney has a penchant for changing his views.

Ecopolitology.org's Timothy Hurst has named the campaign's climatye change "sceptics" as Texas Gov. Rick Perry, Rep. Michelle Bachmann and Herman Cain.

Perry maintains that "the theory of climate change is a hoax concocted by data-manipulating scientists to keep research money coming in to their projects."

Bachmann said there is no reason to worry about carbon dioxide because it is a natural product of nature.

On the other hand, Cain does not consider environmental protection as among his main concerns.

Newt Gingrich, Rep. Ron Paul and Sarah Palin were also described as flip-floppers on the issue.

A former environmental studies professor, Gingrich once appeared to be satisfied with the scientific community's position that human activity is causing climate change. He has now moved from the position that "the evidence is sufficient" to one where he now says there should be public hearings on climate change and the National Academy of Sciences findings vis-à-vis climate, according to Hurst.

Paul proposed solutions for carbon pollution and the next day called global warming a hoax and questioned climate science.

Former Alaska governor Palin said she does not attribute climate change to being manmade and later stated that the causes were not important.

Romney was said to be a believer until after his sudden change of heart.

Former Utah Gov. John Huntsman said he respected science and believed in anthropogenic climate change and is willing to talk about policy solutions to address it.

A Romney spokesperson said his vision on climate change has not altered and that he believes it is happening and that human activity contributes to it, but he does not know to what extent, according to the National Review.