[secretagent]

According to the NG article, mainstream climate experts say the Mars warm up comes from wobbles in Mars' orbit, not an increase in solar heating;

{snip... 'The conventional theory is that climate changes on Mars can be explained primarily by small alterations in the planet's orbit and tilt, not by changes in the sun.

"Wobbles in the orbit of Mars are the main cause of its climate change in the current era," Oxford's Wilson explained. (Related: "Don't Blame Sun for Global Warming, Study Says" [September 13, 2006].' snip...}

http://news.nationalgeographic.com/news/2007/02/070228-mars-warming.html

[DBrow]

Likewise on Earth, Milankovitch Cycles are responsible for the series of ice ages we've had for the last 3 million years or so. In other words, global warming and cooling caused by our orbital fluctuations.

Most climatologists see solar output variations as being minor compared to orbital forcing.

Personally, I think the sun may be more variable now than before and may play a bigger role, but I'm not a climatologist (I do read many papers on solar output though).