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11Climate change 101 Approximately half of the observed sea level rise is believed to be attributable to the slight warming of the ocean. Additionally, the melting of continental ice (ice currently covering land) and its subsequent runoﬀ into the oceans that raises sea level. Warmer water is also less dense and therefore the same mass of ocean takes up more volume (raising the average level ) - this is called the ‘steric eﬀect’. 2012 was the hottest year on record It was also the year where the world witnessed an unprecedented melting of Arctic sea ice. Sea ice melting does not raise sea level. However, it does turn a very reﬂective area (ice) into a very dark and absorbing area (ocean) This is known as the ice albedo feedback, and is the real worry in climate science Sea ice melting does nothing to raise sea level, but it does change the color (and therefore the solar absorption) of the polar oceans. Sea level rise will impact 56% of the global population, all of whom live in regions vulnerable to sea level rise and increased flooding. For example, Superstorm Sandy that hit New York City, New Jersey and other U.S. Eastern States in 2012, disrupted major metropolitan areas where millions of people live and led to: • Transportation systems (road, rail, ports) were destroyed or disrupted due to extreme flooding • Wastewater and stormwater systems were overwhelmed by the unprecedented extreme floods • Electricity & power infrastructures that have not been upgraded to withstand increased flooding and sea level rise were also compromised and many people lost power Global warming = Overall warming of the planet, based on average temperature over the entire surface Climate change = Changes in regional climate characteristics, including temperature, humidity, rainfall, wind and severe weather events. It is understood that both of these are happening simultaneously and that with extreme weather events that there can be colder weather happening regionally as well, which can be confusing to understand how the earth is warming. Climate change can be natural or caused by changes people have made to the land or atmosphere. Sea Level Rise

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