Thank you for the request, I'll try to get it straight - - -
IMO, geoengineering and climate engineering are two completely different subjects or disciplines, although they can interact, possibly in unexpected ways.
Geoengineering is already being done on relatively small scale when humans shave off one side of a hill to try to make the wind in a baseball stadium be a little different than it was when the entire hill was still there. Yes, that was actually done! The San Francisco Giants baseball team found that the winds in Candlestick Park were making high fly balls go in unexpected directions, so they had the entire side of a hill carved away to try to "fix" that. It didn't really do what they wanted, I think - - the winds were still erratic.
Climate engineering is something we still haven't the ability to do properly. Deforestation changes LOCAL weather patterns quite visibly, and has wider impact than most people understand. Planting tall trees along the edges of fields during the Dust Bown years in the USA allowed farmers to retain most of their remaining topsoil by slowing down the wind velocity near ground surface. But the Dust Bowl was caused by a naturally-occurring drought, and farmers didn't think to not plow their fields when crops died. But large-scale climate engineering is far beyond our current abilities to do, and still survive. Yes, we could cause a nuclear winter by having a large nuclear war, but nobody sane wants that.
As a writer of science fiction, I can discuss "terraforming" a dead planet, even moving its orbit to place it in the desired part of the "goldilocks" zone about a star, but of course we haven't the technology to actually do any of that just yet.
So for the time being, we'll just have to admit that our local star has far more influence on our climate than do we puny human beings. But we can do things to not mess up our world, such as not overpopulating the place, such as not mismanaging our forests into firetraps, such as not wasting our resources, such as doing everything we can to not pollute our air and water, such as not overfishing our oceans . . .
The next Ice Age will wipe out the majority of humanity, assuming humans haven't killed themselves off by that time. But the planet itself will go on, with or without us, and simply won't care.
I don't think humans are smart enough, certainly not now, to go about deliberately trying to mess with our global climate. And no, I don't think that so far we've had any major impact on global temperatures. That doesn't mean we shouldn't reduce wasting our resources, but it also means that we really ought to be doing really serious research on nuclear FUSION power so we will have adequate electrical energy late in this century or early in the next.