As the media fail to mention the vital second element required for more than a single degree of harmless warming, plus the fact we already know it is not just absent but replaced by cooling cloud cover then it explains pretty fully that temperatures have risen about 80% less than the UN forecast in the 1990s and growing further and further away from their sharply rising estimates every year. There is no known or expected delay mechanism whereby anything would change, but the oceans evaporate and we can only observe the results after the event. In fact the layers of atmosphere have different effects for both types of water vapour, some warm and some cool, and as a result such phenomena are impossible to model at all so can't be known until after the event. As we now do.
Full details here