Why this principle matters
Climate change discussions often become confused when natural climate cycles are used to dismiss human-caused warming. This principle prevents that mistake. It accepts that natural cycles exist, but it also explains why the current warming trend is different in speed, scale and cause.
Natural variability influences climate over seasonal, decadal and long-term geological timescales. Human forcing, especially the rise of greenhouse gases from fossil fuels and land-use change, has added a powerful warming influence to the Earth system.

