Transient climate response

Transient climate response (TCR)

The TCR is defined as the immediate change in global average surface temperature as a result of doubling the atmospheric CO₂ concentration over a period of 70 years, at a rate 1% per year (compounded), measured by taking the average global temperature over a 20-year period centered at year 70, i.e., 60 – 80 years after the increase starts.

TCR represents the immediate warming effect of carbon dioxide, while the more commonly-cited ECS (equilibrium climate sensitivity) measures the long-term warming effect.