Essay:Natural and artificial causation
When the conclusion favors their preformed views, liberals support natural causation. For example, the increased variety in species of plants and animals seen in the fossil record must be caused by natural factors (see evolution). But when required, they switch their preference for causation to artificial (or man-made). The last century or so of global warming must be due to artificial causes.
Liberals are not scientific, in any objective sense. They make their choices about the type of causation not based on any evidence, but on what suits their ideology. They believe that there is no God (or that God even if He exists has no relevance to human affairs). So human beings had to have come into existence through natural causes only. But they also believe that centralized committees should control all economic activity (with them holding the reins of power), so they promote the theory of anthropogenic global warming. They deny that natural factors (such solar variability can account for the temperature variations in the past 50 to 150 years. Rather, they assert that increased emissions of CO2 and the like are responsible. That gives them justification for controlling and licensing these emissions.