The climate is already changing, the goal is to reduce the amount of change.
The problem is the effort is not to reduce the amount, the effort is to send change, however slightly, in a VERY BAD direction.
We already know the Earth will enter a glacial period again. It may even be tending to do so now, we really don't have the understanding of climate to say for sure.
What we do know is that entering a glacial period is something we would vastly rather avoid over any of the climate warming models to date (now that we know runaway warming is simply not going to happen as the doomsayers predicted). Glacial periods will mean mass extinctions all over, and a huge shortage of arable land unlike the greatly expanded land that can be used for agriculture in a warmer Earth scenario.
It's fine to come up with ideas that promote the reduction of things that in theory increase warming, but it's extremely dangerous (or at least stupid) for life on Earth to do anything on a large scale that promotes global cooling of the atmosphere.