I think people are underestimating the amount of energy production required for sustainability. We use fossil fuels in many other applications besides turning into combustion fuels and if we want to start scrubbing CO2 so we don't turn into Venus that is even more energy. Take fertilizer production for example, we already know it is an energy intensive proccess, a large portion of global energy supply is used on making fertilizer, but it goes farther than that. The base reagents we turn into solid or liquid synthetic fertilizer is more fossil fuels which doesn't get accounted for as energy production, yet it is containing a ton of energy still. We could draw what we need for the fertilizer from the atmosphere and water, but it will increase our energy expenditures for production an entire order of magnitude higher, if not more. Who is counting the carbon pollution from that fertilizer after it comes out of my ass or rots on the ground? The same goes with other processes and materials. Plastics is a big one, nobody counts the amount of 'energy' stored within plastic as a material, plastic doesn't easily degrade, but it does degrade and release its decomposition products into the earth and atmosphere, and at increasing rates if we take the reports of plastic-consuming bacteria evolving and gaining numbers seriously.

I do not know about the effects of plastic decomposition on the climate.

But the replacement of animal products by vegan food is the only sane choice for medical, ethical, economic and ecological reasons.

http://www.cowspiracy.com/

http://www.whatthehealthfilm.com/

https://www.youtube.com/channel/UCGJq0eQZoFSwgcqgxIE9MHw/vid...

https://www.youtube.com/channel/UCJRjK20fHylJyf-HiBtqI2w/vid...

This is probably true, but they should still be researched in case they become useful in other settings, e.g. Mars, or even places on Earth with poor renewable energy potential

A big problem with Mars is that getting fuel there is expensive, they sometimes have large dust storms, and their atmosphere is very thin. Solar power would work fine there 90+% of the time, but outside of fission, there doesn't seem to be any good technology for powering a human habitat over long periods. A rich thorium deposit on Mars could go a long way in creating a self-sustainable habitat. Some thorium reactor designs are notable for their high inherent safety, which is probably a big concern for any human habitat on Mars for morale reasons (think about how much a fatal nuclear disaster on a Martian colony would scare people about space exploration)

I agree.

But going to Mars in the next decades is a useless horrific suicide mission that only serves to make a few people famous.

IMO persons will colonize moons, planets and space ships once their biological body is replaced by a machine body. In a biological sense, the human race will die on Earth.

I agree that focusing on Mars soon is useless, but in the near-term Thorium could be useful for non-windy locations near the poles.