The novel aspects of the research proposed for SHARP are based on the hypotheses that a) climate change caused by the increase of GHG concentrations induces stratospheric changes, and that b) these stratospheric changes interact with the troposphere to influence future tropospheric climate and weather. The main subject of SHARP will therefore be the synergistic investigation of the vertical interaction in the atmosphere related to climate change, i.e. to introduce the aspect of vertical coupling into the discussion of climate change. This goes beyond the approaches of the recent assessments of (tropospheric) climate change (IPCC, 2007) and stratospheric O₃ change (WMO, 2007). 

In SHARP we expect to achieve substantial scientific progress in the following, innovative key issues:

• The detection, investigation and explanation of recent and potential future changes in the Brewer-Dobson circulation (BDC) and their implications for stratospheric dynamics, physics and chemistry in a changing climate based on atmospheric observations and simulations of improved CCMs and GCMs.
• The detection and attribution of changes in O₃ during the anticipated turnaround of chlorine loading and the prediction of O₃ change in response to and as a result of feedback with global climate change.
• The explanation of recent stratospheric H₂O concentration changes based on extended ground based and satellite time series in conjunction with respective model studies, and a reliable assessment of future H₂O concentrations based on improved understanding of the relevant processes in the past.
• The attribution and prediction of changes in tropospheric weather and climate in response to stratosphere-troposphere coupling and understanding of the underlying mechanisms based on atmospheric observations and simulations of CCMs and GCMs.