Neither Mars travel nor reducing energy consumption is going to happen by the individual people magically choosing to do the right thing required for that goal. In general, our societies don't work like that, achieving such things requires coordination to create/enforce appropriate incentives for each individual.

Going to Mars requires a large organization (or a bunch of them) creating significant incentives for people to work on that goal, i.e., paying $bignum to many employees and suppliers - or it's not going to happen.

In the exact same manner, practically reducing energy consumption would require a large organization (or a bunch of them) creating significant incentives for people to reduce consumption, e.g. governments enforcing a significant carbon tax that raises the cost of electricity so much (or some other policy that brings visible, practical impact on each particular individual depending on their actions) that untold millions of people will be strongly motivated to change their habits - or it's not going happen.