Natural vs Human-Caused

Climate skeptics sometimes argue that the greenhouse effect is natural, so current warming must be natural too. This confuses the mechanism with the magnitude. The natural greenhouse effect kept pre-industrial CO2 at around 280 parts per million for thousands of years.

The rate of change matters as much as the total. Past natural climate shifts unfolded over thousands to tens of thousands of years, giving ecosystems time to migrate and adapt. Current warming is happening roughly ten times faster than any natural shift in the geological record.