There is good news and bad news.
The bad news is that, unfortunately, we cannot reverse global warming. There are methods of removing carbon dioxide from the atmosphere, and there has been a lot of exciting work done to further develop them, but it is unlikely that we will actually be able to remove more carbon than we emit with all our other activities. Basically, removing carbon dioxide from the atmosphere will just cancel out some of what we emit. Also, we have actually been putting greenhouse gases in the atmosphere faster than the climate can change, so even if we stopped emitting greenhouse gases today, Earth would keep warming for tens to hundreds of years.

The good news is that we CAN stop emitting greenhouse gases, and if we do that, the warming WILL EVENTUALLY stop. Life is very resilient, and people are very adaptable, so as long as the change is not too fast, we can find ways to go on living. So can other creatures. The key is to cut back on emissions as quickly as possible, so that the climate can start to stabilize. Eventually, the world may look quite different, but it will still be our home if we work hard enough to save it.

Not really, no.

Climate change is something that has happened in the past, is happening now, and will happen in the future, whether we humans are involved in it or not. Climate change also causes species to become extinct, has in the past, and will in the future. The fact that we humans are making climate change worse means that more species are going to become extinct than would have had humans not caused global warming, but some species would have gone extinct anyway.

The global warming that we are causing is due to us burning fossil fuels and releasing greenhouse gasses (mainly carbon dioxide) into the air. The more we burn, the more global warming will happen. The less we burn, the less global warming will happen. We have already burned some, though, which means that some global warming will and is happening, and even if we stopped burning fossil fuels right now, the carbon dioxide that we have already released is still in the air and will still cause warming, just not as much as if we keep burning more fossil fuels.

Also, species become extinct because of climate change, which includes both climate warming and climate cooling. Thus, even if we were to somehow cause global warming to reverse and become global cooling, doing so would still cause species to become extinct.

Yes, slowly -

Reverse global warming.