Indeed, it does. Without the greenhouse effect, and GHG’s, the earth would be too cold for life as we know it to have evolved.
However, too much of a good thing is not a good thing. That could not be more true than with carbon dioxide in our air. We are putting in more than can be removed by natural processes of life – primarily photosynthesis – and it is building up.
Hence, heat is increasing beyond the relative stability we have enjoyed for hundreds of thousands of years.