Mass population-level mortality  and resulting abrupt ecological changes can be caused by simple or compound climate extreme events, such as exceedance of upper thermal limits by vulnerable terrestrial species , who also note reduced mass mortality trends due to extreme low thermal events; marine heatwaves that can cause mortality, enhance invasive alien species establishment, and damage coastal ecological communities and small-scale fisheries  ; and increased frequency and extent of wildfires that threaten populations dependent on habitat availability . Abrupt ecological changes are widespread and increasing in frequency , and include tree mortality due to insect infestation exacerbated by drought, and ecosystem transformation due to wildfire . Freshwater ecosystems and their biodiversity are at high risk of biodiversity loss and turnover due to climate change , due to high sensitivity of processes and life histories to thermal conditions and water quality  . In marine systems, heatwaves cause damages in coastal systems, including extensive coral bleaching and mortality  , mass mortality of invertebrate species  , and abrupt mortality of kelp-forest   and seagrass-meadow habitat  . The biodiversity of polar seas shows strong impacts of climate change on phenological timing of plankton activity, Arctic fish species range contractions and species community change  . Extreme weather events and storm surges exacerbated by climate change have severe and sudden adverse impacts on coastal systems, including loss of seagrass meadows and mangrove forests  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report