Despite their vital social and ecological value, substantial declines in seagrass communities have been documented in many small islands , including Fiji , Reunion Island , Bermuda, Cayman Islands, US Virgin Islands , Kiribati , Federated States of Micronesia, and Palau , but attribution of such declines to climatic influences remains weak . The impact of climate change on seagrasses goes beyond the loss of seagrass but includes acceleration of seagrass decomposition , palatability  and the cumulative effect of warming and eutrophication . Seagrasses face a multitude of threats including physical disturbance and direct damage caused by rapidly growing human populations, declines in water quality, and coastal erosion . Experimental studies have shown increased mortality, leaf necrosis, and respiration when seagrasses are exposed to higher-than-normal temperatures . As such, seagrass meadows growing near the edge of their thermal tolerance are at risk from rising temperatures . In the Mediterranean, seagrass meadows are already showing signs of regression, which may have been aggravated by climate change . Some studies suggest seagrasses have potential for acclimation and adaptation . Chefaoui et al.  attempted to forecast the distribution of two seagrasses in the future, including around the islands of Cyprus, Malta, Sicily and the Balearic Islands. Under the worst-case scenario, Posidonia oceanica was projected to lose 75% of suitable habitat by 2050. Conversely, it has been suggested that seagrasses could actually benefit from an increase in anthropogenic CO2because of increased growth and photosynthesis . However, Collier et al.  argued that when faced with increased heat waves, thermal stress will rarely be offset by the benefit of elevated CO2 and therefore that the widespread belief that seagrasses will be a 'winner' under future climate change conditions seems unlikely .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report