FN Archimer Export Format
PT J
TI Increase in ocean acidity variability and extremes under increasing atmospheric CO2
BT 
AF BURGER, Friedrich A.
   JOHN, Jasmin G.
   FROLICHER, Thomas L.
AS 1:1,2;2:3;3:1,2;
FF 1:;2:;3:;
C1 Univ Bern, Phys Inst, Climate & Environm Phys, Bern, Switzerland.
   Univ Bern, Oeschger Ctr Climate Change Res, Bern, Switzerland.
   NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA.
C2 UNIV BERN, SWITZERLAND
   UNIV BERN, SWITZERLAND
   NOAA, USA
IN DOAJ
IF 4.295
TC 49
UR https://archimer.ifremer.fr/doc/00676/78825/81141.pdf
   https://archimer.ifremer.fr/doc/00676/78825/81142.pdf
LA English
DT Article
CR OISO - OCÉAN INDIEN SERVICE D'OBSERVATION
AB Ocean acidity extreme events are short-term periods of relatively high [H+] concentrations. The uptake of anthropogenic CO2 emissions by the ocean is expected to lead to more frequent and intense ocean acidity extreme events, not only due to changes in the long-term mean but also due to changes in short-term variability. Here, we use daily mean output from a five-member ensemble simulation of a comprehensive Earth system model under low- and high-CO2-emission scenarios to quantify historical and future changes in ocean acidity extreme events. When defining extremes relative to a fixed preindustrial baseline, the projected increase in mean [H+] causes the entire surface ocean to reach a near-permanent acidity extreme state by 2030 under both the low- and high-CO2-emission scenarios. When defining extremes relative to a shifting baseline (i.e., neglecting the changes in mean [H+]), ocean acidity extremes are also projected to increase because of the simulated increase in [H+] variability; e.g., the number of days with extremely high surface [H+] conditions is projected to increase by a factor of 14 by the end of the 21st century under the high-CO2-emission scenario relative to preindustrial levels. Furthermore, the duration of individual extreme events is projected to triple, and the maximal intensity and the volume extent in the upper 200 m are projected to quintuple. Similar changes are projected in the thermocline. Under the low-emission scenario, the increases in ocean acidity extreme-event characteristics are substantially reduced. At the surface, the increases in [H+] variability are mainly driven by increases in [H+] seasonality, whereas changes in thermocline [H+] variability are more influenced by interannual variability. Increases in [H+] variability arise predominantly from increases in the sensitivity of [H+] to variations in its drivers (i.e., carbon, alkalinity, and temperature) due to the increase in oceanic anthropogenic carbon. The projected increase in [H+] variability and extremes may enhance the risk of detrimental impacts on marine organisms, especially for those that are adapted to a more stable environment. 
PY 2020
PD SEP
SO Biogeosciences
SN 1726-4170
PU Copernicus Gesellschaft Mbh
VL 17
IS 18
UT 000575775800001
BP 4633
EP 4662
DI 10.5194/bg-17-4633-2020
ID 78825
ER

EF