Over the past few decades, sea levels worldwide have risen because of three primary phenomena related to climate change: the expansion of warming oceans, the input of fresh water from melting ice sheets and the loss of ice mass from Greenland and Antarctica (see the Near Real-Time Environmental Event Alert on page 7) (Climate Institute 2010). Rising seas threaten millions of people who live in densely populated coastal areas and low-lying islands, so it is critical for risk management purposes to estimate and prepare for the impacts of future sea-level rise and to be aware of regional differences.