Denial: “It’s the sun”
Answer: The sun’s output has barely changed since 1970 and is irrelevant to recent global warming.
Denial: “Climate’s changed before”
Climate reacts to whatever forces it to change at the time, which now is dominated by humans.
Denial:“There is no consensus”
Answer: 97% of climate experts agree humans are causing global warming.
The last decade 2000-2009 was the hottest on record.
I've posted a few suggestions too...
Denial:“Other planets are warming”
Answer: The other planets in our solar system do not support life. Lets focus on planets that do.
Denial:“Climategate CRU emails suggest conspiracy”
Answer: Then the Pacific oyster must be part of the conspiracy as it’s breeding in now warmer waters that only a few years ago it could not survive in.
Denial:“Polar bear numbers are increasing”
Answer: Polar bear encounters are increasing around human settlements as widen the search for food due to ice loss, but sadly overall numbers are on the decline.
Denial:“Pluto is warming”
Answer: That idea is based on 2 measurements 14 years apart whereas Pluto’s orbit is takes 248 Earth years; it proves nothing about nothing.
Lots more here...