Well, different scholars approach the study differently. However, your question sounds like one of my research themes. I am relatively new to this research, but I can offer a starting point from climate change perspective.
You may want to start by looking at the IPCC's new scenario process, which comprises of three independent scenarios for climate (or so-called the RCPs), socioeconomic (or so-called the SSPs), and climate policies (or so-called the SPAs). The interaction between socioeconomic and climate change can be analyzed using an approach which is sometimes called 'scenario pairing,' that is SSP scenario x RCP scenario. For more detail on this method, you can look up O'Niell et al. (2013). The measure of consistency for a particular SSPxRCP combination is analyzed computationally or intuitively. The scenario process requires you to conduct a study which is specific to your sector/location. The work of Kemp-Benedict and his colleagues on Forest Futures (2014) provides a very comprehensive (IMO) guideline of the scenario 'downscaling' from global SSPs to a particular biophysical system at a regional level. For your case, you may want to 'extend/downscale' the SSPs for coastal regions.
If there is a requirement for the information on the interaction be explicit, the use of cross-impact matrix can potentially address this. You can take a look at Weimer-Jehle paper on the theoretical concept of Cross-Impact Balances Analysis and Schweizer & O'Neill (2013) for the application of CIB for scenario process under the SSPs framework.