Vollbericht: All model-based analyses since AR4 broadly confirm this concern, leading to high confidence that climate change will contribute to increased extinction risk for terrestrial and freshwater species over the coming century (Pereira et al., 2010; Sinervo et al., 2010; Pearson, 2011; Warren et al., 2011, 2012; Bellard et al., 2012; Hannah, 2012; Ihlow et al., 2012; Sekercioglu et al., 2012; Wearn et al., 2012; Foden et al., 2013). Most studies indicate that extinction risk rises rapidly with increasing levels of climate change, but some do not (Pereira et al., 2010). The limited number of studies that have directly compared land use and climate change drivers have concluded that projected land use change will continue to be a more important driver of extinction risk throughout the 21st century (Pereira et al., 2010). There is, however, broad agreement that land use, and habitat fragmentation in particular, will pose serious impediments to species adaptation to climate change as it is projected to reduce the capacity of many species to track climate (see Section 22.214.171.124.3). These considerations lead to the assessment that future species extinctions are a high risk because the consequences of climate change are potentially severe, widespread, and irreversible, as extinctions constitute the permanent loss of unique life forms.
Most plant species cannot naturally shift their geographical ranges sufficiently fast to keep up with current and high projected rates of climate change in most landscapes; most small mammals and freshwater molluscs will not be able to keep up at the rates projected under RCP4.5 and above in flat landscapes in this century (high confidence).
Synthese des Einzelberichts
Within this century, magnitudes and rates of climate change associated with medium- to high-emission scenarios (RCP4.5, 6.0,and 8.5) pose high risk of abrupt and irreversible regional-scale change in the composition, structure, and function of terrestrial and freshwater ecosystems, including wetlands (medium confidence). Examples that could lead to substantial impact on climate are the boreal-tundra Arctic system (medium confidence) and the Amazon forest (low confidence).
2) small mammals and freshwater mollusks
“Species shifts”, also die Geschwindigkeit mit der Arten ihren Standort aendern können sind insbesondere in Abbildung SPM5 zu finden. Sowohl freshwater mollusks als auch small mammals (rodents) sind dort aufgeführt. Beide sind (Median Wert) in ihrer “Habitatgeschwindigleit” unter den RCP6 und RCP8.5 für flat areas. Siehe Abbildung 1.
Abbildung 1: Vergleich von Migrationsgeschwindigkeiten verschiedener Fauna und Flora Species mit den prognostizierten Geschzindigkeiten, mit denen der Klimawandel in verschiedenen Terrains und unter unterschiedlichen Klimawandelscenarios voranschreitet.
Future risk is indicated to be high by the observation that natural global climate change at rates lower than current anthropogenic climate change caused significant ecosystem shifts and species extinctions during the past millions of years. Marine organisms will face progressively lower oxygen levels and high rates and magnitudes of ocean acidification (high confidence),
Synthese des Einzelberichts
See Figure SPM.2B. While only a few recent species extinctions have been attributed as yet to climate change (high confidence), natural global climate change at rates slower than current anthropogenic climate change caused significant ecosystem shifts and species extinctions during the past millions of years (high confidence).
Ferner findet sich dort Abbildung SPM6.b mit der Beschreibung
Abbildung 2 (original caption aus dem SPM WGII): (B) Marine mollusk and crustacean fisheries (present-day estimated annual catch rates ≥0.005 tonnes km-2) and known locations of cold- and warm-water corals, depicted on a global map showing the projected distribution of ocean acidification under RCP8.5 (pH change from 1986-2005 to 2081–2100). [WGI AR5 Figure SPM.8].The bottom panel compares sensitivity to ocean acidification across mollusks, crustaceans, and corals, vulnerable animal phyla with socioeconomic relevance (e.g., for coastal protection and fisheries). The number of
species analyzed across studies is given for each category of elevated CO2.