What can we learn about climate feedbacks from short-term climate variations?

This study examines the radiative feedbacks resulting from changes in the climate over the last 30 yr. These ‘short-term’ feedbacks correspond to both external changes in the forcing [from greenhouse gases (GHGs), aerosols etc.] and internal climate variations [mostly due to El Ni o Southern Oscillation (ENSO)]. They differ from the ‘long-term’ (century scale, mainly due to GHG warming) feedbacks both in magnitude (by 24% on the global average) and geographical distribution, according to the Coupled Model Intercomparison Project phase 3 multi-model dataset. In addition, the inter-model spread of the short-term feedbacks is larger than the long-term ones even for the models with the best ENSO performance, which indicates that important aspects of the ENSO variability are still poorly understood and/or simulated. Information from observations and from advanced reanalysis systems can be very useful to improve the model short-term climate responses. However, long and accurate observational records are critical in order to obtain confident results.