Sea level is rising faster in recent decades. Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers and the expansion of seawater as it warms. Sea level rises will cause inundation of low lying land, islands and coastal cities globally.

As sea level rises higher over the next 15 to 30 years, tidal flooding is expected to occur much more often, causing severe disruption to coastal communities, and even rendering some areas unusable - all within the time frame of a typical home mortgage.

2°C warming would threaten to inundate areas now occupied by 130 million people while increase to 4°C could lock in enough eventual sea level rise to submerge land currently home to 470 to 760 million people globally.

The land ice sheets in both Antarctica and Greenland have been losing mass since 2002. Both ice sheets have seen an acceleration of ice mass loss since 2009. Antarctica is losing six times more ice mass annually now than 40 years ago.

In 2014 a team from NASA found that part of the West Antarctic ice sheet had already begun what they described as an "unstoppable" collapse, locking in at least a meter of sea level rise. If we continue warming we will trigger the collapse of more sectors of the ice-sheets.

"Sea level is rising much faster and Arctic sea ice cover shrinking more rapidly than we previously expected. Unfortunately, the data now show us that we have underestimated the climate crisis in the past." Stefan Rahmstorf, Professor of Physics of the Oceans