Das Bild zeigt den prognostizierten (praktisch immer mehrheitlich negativen) Effekt auf diese Populationen (Krustazeen, Mollusken etc.) bei verschiedenen möglichen CO2 Gehältern.
Vollbericht:
gibt Beispiel für Massenaussterben während der letzten Millionen Jahre (PETM, 55 Mill.BP) mit gleichzeitiger starker Erwärmung und starkem CO2 Anstieg und ca. 50% Aussterben der benthischen Foraminiferen Arten (Seite 422). Von mir sei angemerkt, dass das Aussterben der großen Säuger während des Quartärs (30000-10000 yr BP) in der wissenschaftlichen Diskussion nachwievor mit schnellen Klimaschwankungen am Ende der letzten Eiszeit in Verbindung gebracht wird (entweder als alleiniger Faktor oder zusammen mit dem anderen Hauptstress für diese Arten, nämlich die Bejagung durch steinzeitliche Jäger). Das gilt ähnlich auch für eine uns sehr nahestehende Art grosser Säuger: den Neanderthalern.
Zitat (S.280)
Excellent examples of past large climate change events that drove large ecological change, as well as recovery periods in excess of a million years, include the events that led to the Earth’s five mass extinctions in the distant past (i.e., during the Ordovician, about 443 Ma, the Devonian, about 359 Ma, the Permian, about 251 Ma, the Triassic, about 200 Ma, and the Cretaceous, about 65 Ma; Barnosky et al., 2011). Major ecological change was also driven by climate change during the Paleocene-Eocene Thermal Maximum (PETM, 56 Ma; Wing et al., 2005; Jaramillo et al., 2010; Wing and Currano, 2013), the early Eocene Climatic Optimum (EECO, 53 to 50 Ma; Woodburne et al., 2009), the Pliocene (5.3 to 2.6 Ma; Haywood and Valdes, 2006; Haywood et al., 2011), and the Last Glacial Maximum (LGM) to Holocene transition between 21 and 6 ka (MacDonald et al., 2008; Clark et al., 2009; Gill et al., 2009; Williams, J.W. et al., 2010; Prentice et al., 2011; Daniau et al., 2012). The paleoecological record thus provides high confidence that large global climate change, comparable in magnitude to that projected for the 21st century, can result in large ecological changes, including large-scale biome shifts, reshuffling of communities, and species extinctions.
Synthesereport
with associated risks exacerbated by rising ocean temperature extremes (medium confidence).
Synthese des Einzelberichts
In Tabelle SPM.A1 sind für verschiedene Spezies und Regionen einzeln diskutiert, ob sie erhöhtem Stress und eventuell dem Aussterben bedroht sind. Ich fand folgende Bemerkungen:
Australasia: Ability of corals to adapt naturally appears limited and insufficient to offset the detrimental effects of rising temperatures and acidification.
Ocean: Evolutionary adaptation potential of fish and invertebrate species to warming is limited as indicated by their changes in distribution to maintain temperatures.
Synthesereport
Coral reefs and polar ecosystems are highly vulnerable. Coastal systems and low-lying areas are at risk from sea –level rise, which will continue for centuries even if the global mean temperature is stabilised (high confidence). {2.3, 2.4, Figure 2.5}
Synthese des Einzelberichts
1) Corals: Evidence of rapid evolution by corals is very limited. Some corals may migrate to higher latitudes, but entire reef systems are not expected to be able to track the high rates of temperature shifts.
2) Polar ecosystems:
a) Increased shrub cover in tundra in North America and Eurasia ( high confidence, major contribution from climate change)
b) Advance of Arctic tree-line in latitude and altitude ( medium confidence, major contribution from climate change)
c) Changed breeding area and population size of subarctic birds, due to snowbed reduction and/or tundra shrub encroachment ( medium confi dence, major contribution from climate change)
d) Loss of snow-bed ecosystems and tussock tundra ( high confidence, major contribution from climate change).
e) Impacts on tundra animals from increased ice layers in snow pack, following rain-on-snow events ( medium confi dence, major contribution from climate change)
f) Increased plant species ranges in the West Antarctic Peninsula and nearby islands over the past 50 years ( high confi dence, major contribution from climate change)
Kommentare (155)