Global warming is an amazingly difficult subject to figure out on one's own. There is a long term warming as the Ice Age (ignorantly said to have ended 15,000 years ago) continues to end. There are also shorter term periods of warming and cooling, such as the Little Ice Age which was a period of unusually cool weather between 1500 and 1900. There are also shorter terms trends of a few years or decades. The trick is, among all that signal noise, to ascertain if there is a new effect caused by human activity. No small thing to figure out. But there seems to be a consensus among scientists that there is an effect.
My own opinion (which I would remind you is worthless because I do not actually know squat about it) is that the world was slowly warming anyway, and that all our exhaust pipes and smokestacks have greatly accelerated it.
What is less clear is the basis for the assumption that global warming is automatically a bad thing. The warning that it will cause coastal flooding because of higher sea levels does not persuade me as much as it does others. Most buildings are replaced by newer ones within a generation or two anyway. Rising sea levels means that they will just have to be built further inland. I do not think that is such a disaster. Other places can be protected with dikes as the Netherlands is. Many of California's Delta islands are surrounded by levees and are lower than the water that surrounds them.
Some areas now temperate will become desert, but some deserts will become arable. As with any big change there will be winners and losers. Cold countries like Alaska, Canada, Greenland, Iceland, Scandinavia, Russia, and Siberia will be winners. What are now vast subarctic barrenlands will become pleasant temperate countryside. Humanity might gain a whole new continent to live on as the Antarctic ice sheet melts.
My own reason for not wanting global warming has nothing to do with all these arguments which I lump under the heading of "bitching about change". The real downside of global warming is that too-rapid climatic change causes widespread extinctions of species which cannot adapt quickly enough. New species to replace them evolve slowly, far slower than human affairs can consider. So many species are already under so much pressure from other human activities which restrict their habitats, that the extinctions could be on a very wide scale. Being myself a plant and/or animal, I prefer that there be as many kinds of plants and animals in the world as possible. Maybe just because so many of them are beautiful.