Global synchrony of an accelerating rise in sea surface temperature

Abstract

International audienceThe oceans have shown a recent rapid and accelerating rise in temperature with, given the close link between temperature and marine organisms, pronounced effects on ecosystems. Here we describe for the first time a globally synchronous pattern of pulsed short period (~1 year long) emanations of warm sea surface temperature anomalies from tropical seas towards the poles on the shelf/slope with an intensification of the warming after the 1976/1977, 1986/1987 and 1997/1998 El Niños. On the eastern margins of continents the anomalies propagate towards the poles in part by largely baroclinic boundary currents, reinforced by regional atmospheric warming. The processes contributing to the less continuous warm anomalies on western margins are linked to the transfer of warmth from adjacent western boundary currents. These climate induced events show a close parallelism with the timing of ecosystem changes in shelf seas, important for fisheries and ecosystem services, and melting of sea-ic

Synchronous marine pelagic regime shifts in the Northern Hemisphere

“…We believe these shifts were mediated by an abrupt warming seen in the climate [19,91]. For example, a regime shift during the late 1980s was detected in many large marine regions around the NH, although the exact year of the observed shift varied somewhat from one basin to another.…”

“…These ecosystems, with the exception of the North Sea, were however not analysed in this study. These widespread changes have been attributed to changes in circulation and temperature associated to the strength of the subpolar gyres [54,79] and to global-scale changes in temperature at the end of the 1990s [19].…”

“…Reid & Beaugrand [19] observed that in many cases the reported ecological regime shifts coincided with major temporal changes seen in marine temperature anomalies and suggested that temperature may be an important synchronizing agent.…”

“…In addition, regime shifts were observed in the late 1980s around all European seas [8]: the North Sea [44,45], the Baltic Sea [9,46], the northwest European shelf seas (1987/1990) [47,48], the western [49] and eastern (Adriatic) Mediterranean Sea [8,50,51] and the Black Sea [52,53]. Other shifts have been observed in the late 1990s in the northeast Atlantic and its adjacent seas, in the Black Sea, and in San Francisco Bay [54][55][56][57] at the time of a global shift in temperature [19]. Note that the late 1970s regime followed an abrupt change in the large-scale boreal winter circulation pattern over the North Pacific during the mid-1970s, which affected the thermal regime of these oceanic regions [58,59].…”

“…Important examples of regime shifts in large marine ecosystems have been reported for both the Northern Hemisphere (NH) [6][7][8][9][10][11] and the Southern Hemisphere [12,13]. As studies focusing on pelagic regime shifts around the world increased and became more global, researchers began to examine potential synchronicities in the variation of species and ecosystems that are often separated by great distances, and are even in different ocean basins [1,8,[14][15][16][17][18][19][20][21][22][23][24][25].…”