Pattern decomposition of the transient climate response

Summary of the Climate Dialogue on Climate Sensitivity and Transient Climate Response

2 Introduction Equilibrium Climate Sensitivity (ECS) is a central theme in climate science, as it characterizes the degree of temperature change that would be expected from a given radiative forcing, e.g. from a change in solar output or from a change in atmospheric greenhouse gas (GHG) concentrations. It is usually defined in terms of a doubling of atmospheric CO2 concentrations as a common re...

Extended Summary of the Climate Dialogue on Climate Sensitivity and Transient Climate Response

Transient Climate Response in Coupled Atmospheric–Ocean General Circulation Models

The equilibrium climate sensitivity (ECS) has a large uncertainty range among models participating in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) and has recently been presented as ‘‘inherently unpredictable.’’ One way to circumvent this problem is to consider the transient climate response (TCR). However, the TCR among AR4 models also differs by more tha...

Transient climate response to increasing atmospheric carbon dioxide.

The ocean's role in the delayed response of climate to increasing atmospheric carbon dioxide has been studied by means of a detailed three-dimensional climate model. A near-equilibrium state is perturbed by a fourfold, stepfunction increase in atmospheric carbon dioxide. The rise in the sea surface temperature was initially much more rapid in the tropics than at high latitudes. However, the fra...

The inconstancy of the transient climate response parameter under increasing CO2

In the Coupled Model Intercomparison Project Phase 5 (CMIP5), the model-mean increase in global mean surface air temperature T under the 1pctCO2 scenario (atmospheric CO(2) increasing at 1% yr(-1)) during the second doubling of CO(2) is 40% larger than the transient climate response (TCR), i.e. the increase in T during the first doubling. We identify four possible contributory effects. First, t...