How dangerous is this "Global Warming"?

Ever since the industrial revolution, global warming has started increasing a lot. In the 19th century, global warming wasn't that big of a problem. It didn't affect anyone too drastically. Now in the 21st century, global warming is one of the biggest problems in this world. From the 19th century until the 21st century, the temperature has raised by a little more than 3° C (5.4° F).