The Mediterranean Sea is considered one of the world`s biodiversity hotspots, where the impact of climate change together with other anthropogenic pressures could be most devastating (Lejeusne et al., 2009; Coll et al., 2010) It is outside the scope of this guide to describe in detail all the known impacts on marine biodiversity resulting from the changing climate (see reviews by Gambiani et al., 2009; Lejeusne et al., 2009; Calvo et al.,2011; Di Carlo and Otero, 2013). Instead, it presents an overall review illustrated with examples of the most important effects that are likely to be monitored (or at least reported in MPAs)