I think the group of artists proposing that Letterkenny, County Donegal, should be twinned with Mars, may have got their Climate Change facts a little twisted :-
https://news.bbc.co.uk/1/hi/northern_ireland/foyle_and_west/8473116.stm
“Irish island twinned with Mars in climate change stunt : An island in County Donegal is to be twinned with Mars in order to raise awareness of climate change. A community near Letterkenny will be linked with an island outcrop on the Red planet. The unusual move was suggested by a group of artists asked by Donegal County Council to explore art’s role in addressing issues of global warming. The Council’s Public Arts Manager, Terri Duffy, said it would act as an “attention-grabbing wake-up call”. “I know it’s a bit ‘out there’ but it is taking a very serious look at the relationship of art and climate change. Some people feel the earth is becoming more Mars like due to the effects of global warming…”
Mars is rather cold, owing to the fact that it doesn’t really have much of an atmosphere and so doesn’t have the benefit of much in terms of the Greenhouse Effect :-