Objective

We use an atmospheric general circulation model coupled to a slab ocean to study the effects of ocean heat transport on climate prescribing the transport (OHT) from 0 to 2 times present day values. Background ● The circulation of the oceans likely changed over the course of Earth’s history, due to changes in external forcings (e.g., insolation) and changes in continental configuration. Thus, a change in ocean heat transport is a common explanation in studies of past climates. ● Increased ocean heat transport warms the climate by reducing sea ice extent and low oceanic cloud cover in the tropics and midlatitudes thus reducing the albedo of the planet (Winton 2003), and by increasing the clear-sky greenhouse trapping due to moistened subtropics (Herweijer et al 2005). ● Previous studies imply that further increasing the ocean heat transport from today's conditions will further warm the climate. Here we extend the range of imposed ocean heat transport to two times present-day values to address this issue and study the sensitivity of results to cloud parameterizations. Methodology ● We use ECHAM5 coupled to a slab ocean, where SST evolves according to the following equatio