Abstract

The heat content of the upper 700 m of the global ocean is ~ 120x1021 J higher than in 1995, the equivalent of
~ 240 times the human global energy consumption in 2013.
• Since the 1990s the atmosphere in the polar regions has been warming at about twice the average rate of
global warming.
• There is likely to be further major loss, and possibly the essential removal in some years, of summer Arctic sea
ice in the next 5-15 years.
• The extent of Antarctic sea ice has been growing at a rate of ~1.3% per decade, although there is strong
interannual variability.
• Over the last 20 years there has been a distinct change in the El Niño events, with a shift of the mean location
of sea surface temperature anomalies towards the central Pacific.
• There has been an increase in the number of severe hurricanes (Saffir-Simpson scale 3-5) at a rate of ~ 25-30%
per o
C of global warming.
• There has been an increase in storm surges along Arctic coasts, leading to more frequent inundation of fragile
coastal ecosystems.
• There have been significant increases in iceberg numbers in the ocean since the 1990s.
• There is likely to be an increase in mean global ocean temperature of 1-4o
C by 2100.
• Due to increased stratification of the ocean, the global Meridional Circulation is likely to decline over the next
century, although there is not a consensus as to the rate.
• Uncertainty about the future of most large-scale ocean-atmosphere teleconnections under greenhouse
warming is ubiquitous.