There are two issues that must be separated in the controversy over global warming. The first concerns whether the Earth has warmed significantly in the recent past. The second is the notion that if this warming has occurred, is it due to human activity, specifically to a rise in atmospheric carbon dioxide resulting from industrial activity.
The question of the purported increase in global temperature can be scientifically settled by adequate measurement of temperature; this requires adequate measurement and proper sampling of worldwide temperature and its change over time. The second issue is quite different. While it may be true that global warming has taken place in recent times, the cause of that change remains to be demonstrated. The carbon dioxide hypothesis is plausible since there is little doubt that atmospheric carbon dioxide has increased with the rise of industrialization and there is a known possible mechanism for carbon dioxide to produce a temperature rise. However, these points are not sufficient to make the case. Consider, it is known that there was at least one great ice age. It ended certainly, but how? No doubt due to something that all would recognize as global warming. What caused that warming? There is no strong reason to believe that a rise in carbon dioxide led to the termination of the ice age. Implicit in that suggestion is that there may be other mechanisms than carbon dioxide rise to explain these events. If so, what confidence can one have in the purported role of human activity is responsible for such temperature rise as we have experienced recently?
One may take the stance that the probability is so great that disaster will ensue, action must be taken. And, we only know enough to implicate carbon dioxide in that disaster even though it may not be the culprit, decarbonization is the only option. But science it is not!