Climate sensitivity describes how strongly Earth's surface temperature responds to a change in atmospheric carbon dioxide or other radiative forcing. This lesson introduces the energy balance behind the concept and explains why climate feedbacks affect the amount of warming.
Climate sensitivity is the change in surface temperature in response to a change in atmospheric CO2 concentration or another radiative forcing. It is commonly expressed as the warming expected from a doubling of CO2 compared with its preindustrial concentration of about 280 parts per million (ppm). It can also be expressed as temperature change per unit forcing, in °C/(W/m²).
All flashcards
Transient climate response (TCR)
The 20-year mean global surface warming centered on CO₂ doubling during a simulation with CO₂ rising 1% per year.
Equilibrium climate sensitivity (ECS)
The long-term near-surface warming expected from doubled CO₂ after the climate has largely adjusted.
Earth system sensitivity (ESS)
Climate sensitivity including slow processes such as ice-sheet, vegetation, and ocean-circulation changes; it excludes the carbon cycle.
Transient climate response to cumulative emissions (TCRE)
Global average temperature change associated with emitting 1,000 gigatonnes of CO₂.
Emergent property
A model characteristic that arises from interactions among represented processes rather than being set as a single input.
Quiz questions
In a simulation where CO₂ rises by 1% per year, how is transient climate response (TCR) defined?Answer: The 20-year mean surface warming centered on the time CO₂ doubles.
Why is equilibrium climate sensitivity generally higher than transient climate response?Answer: The deep ocean gradually warms, reducing its temporary buffering of surface warming.
Which processes distinguish Earth system sensitivity from equilibrium climate sensitivity?Answer: Slow changes such as shifts in ice sheets, vegetation, and ocean circulation.
What information is combined in a simple industrial-era energy-balance estimate of climate sensitivity?Answer: Observed warming, radiative forcing, and ocean heat uptake.
In a climate model, what makes climate sensitivity an emergent property?Answer: It results from interactions among modeled processes rather than a single prescribed input.