The 1.5C (and other similar) thresholds are based on pre-industrial averages. An average of between 1850 and 1900 is generally considered to be the modern pre-i

The 1.5C (and other similar) thresholds are based on pre-industrial averages. An average of between 1850 and 1900 is generally considered to be the modern pre-industrial baseline. This is then the average of 2024 as compared to that pre-industrial baseline. The significance of this is the rate at which the planet is warming, which is unprecedented as according to historical data. The rate is what concerns environmental scientists as it means that ecosystems etc. do not have the same time to adapt as compared to pre-historical periods of warming.