I believe most of these out of the box ideas are self-censored because others aren't seen voicing the same idea, resulting in the autonomous conclusion its probably a dumb idea. Most probably are. An unknown fraction are probably prematurely rejected ideas. A community that is openminded to considering these might weed out the good unexplored ideas from the nonsensical unexplored ideas.
I will give an example:
A large majority of humanity lives relatively close to the sea. Thermal energy generation (both nuclear as well as fuel based) requires a hot temperature bath (from fuel, fission or perhaps someday fusion) as well as cold temperature bath to drive a thermal engine. When the colder thermal bath is hotter than usual the efficiency of fuel to electricity is lower, when the colder thermal bath is colder then usual the energy conversion efficiency is higher.
Why don't governments build out "national heat pipes to the sea" ? The pipes themselves don't need to be copper. The working fluid could be benign distilled water in a vacuum. Usage could be metered by thermal gradient at supplier/user interface. The pressure (a slight vacuum in case of distilled water) could be adapted as a function of ocean temperature, for optimal fluid/gas ratio for optimal heat flow and coolant feedback.
Like an artificial ring system for earth.
Something like huge flat mylar mirror sheets with an outer foldable spring rim so they can be packaged small and pop open on deployment.
Using an magnetic field generated by electricity flowing through looped coils on their perimeter they could be angled relative to the Earth's magnetic field.
On the sun side of the orbit each one can be used to cast a controlled amount of shade from parallel to perpendicular.
Enough of them - say 2% of the Sun-facing profile of the Earth could reduce incoming solar radiation by the same amount, but in a controllable fashion.
In other positions they could be used to direct solar radiation to specific areas by pointing their mirror surface at the appropriate angle in orbit.
You could heat up bodies of water to produce cloud cover.
I imagine that you could, with trial and error, and lots of modelling, have a degree of climate and weather control.
building roofs -- maybe even solar panel-powered -- over large swaths of downtowns/cities. i think it's be wild and dystopian and fun. maybe we could start with relatively small installations -- like a few football fields' worth over downtown Phoenix. any building over 6 or so stories gets demolished b/c it's in the way and an abomination anyways.
or
allowing people to bike / roll to places under their own power, and/or possibly with electric power, in small-format (i.e. non-car/truck/bus) ways -- probably by prioritizing bike and roll traffic above all other modes, including walking. think Dutch/Danish/German-style biking infrastructure. lots of 4-to-5 lanes street reconfigurations (two car lanes in either direction --> one protected bike lane and one car lane in either direction, with a suicide/turn/middle lane).
or
just build DC-wide sidewalks on every street/highway/freeway in the country/world -- add shade and make the interesting and add water and shelters if necessary. and / or make them all multi-use paths (MUPs), and if you knock someone down or scare them, then you go to jail for life.
and
i generally like the idea of 'renewable' geo energy like that described -- def worth continuing to check out.
I'd like to alter the earth's orbit and axis slightly, myself. There's numerous problems with the idea tho. If you have a lever long enough to move the earth, where do you apply it? The planet isn't that stiff on that scale and we don't wanna crack the egg, just nudge it a bit.