The idea that Mars is also suffering global warming (and therefore Earth's global warming must be a solar sytem wide phenomenon) is based primarily on the work of Lori Fenton in 2007. Read it here:

http://www.nature.com/nature/journal/v446/n7136/abs/nature05718.html

Fenton and co-authors looked at composite photos of Mars from 1977 and 1999 and calculated the global average albedo - finding a decrease that could be interpreted as a warming trend of 0.65 degrees over 22 years.

BUT! These photos are snapshots - showing two instants 22 years apart. Impossible to separate weather from climate with just two photos. Imagine looking at a Northern hemisphere winter picture of Earth in 1977, and northern hemisphere summer picture in 1999. Will they be different? Of course! Will the differences say anything meaningful about climate? Of course not! Seasonal fluctuations are large than global trends (on Mars and Earth).

Trying to disprove anthropogenic global warming on Earth by claiming that there is non-anthropogenic warming on Mars fails on two levels: 1) there is no empirical evidence for warming on Mars, and 2) The climate drivers and sensitivity on Mars are not well understood, but we know they are very different from Earth's (e.g. Mars has little atmosphere, and no macrofauna or macroflora).

It is just silly to think you can argue against anthropogenic global climate change on Earth (where we have abundant data and continuous measurments of many proxies over long periods of time) by citing global warming on Mars (which is based on two snapshots). If one claims that the science regarding Earth's climate is not settled, you can't support this by citing the far less constrained science regarding Mars' climate.

And on to Jupiter...we know even less about climate change, climate drivers, and climate sensitivity on Jupiter than we do for Mars! See above. It's an even sillier argument.