Recent climate studies have debated the issue of whether or how the oceans provide feedback to the atmosphere. Since the oceans store heat and release it on various timescales, defining ocean feedback mechanisms is an important stage in being able to provide climate predictions. Currently model runs are used to determine whether they can simulate either oceanic or atmospheric signals. Some success has been achieved at the interdecadal timescale but often studies still lack independent verification or application to the wider ecosystem. Here it is shown that by use of a simple technique applied to atmospheric data it is possible to derive climate indices that capture the non-linear feedback response of the ocean-atmosphere climate system. These indices may provide an independent means to verify feedback in models at the same time as bridging the gap between the fields of atmosphere-ocean and ecosystem climate modelling.