Rising seas may be the most tangible impact of a warming climate since 40% of the world’s population lives along coasts. Global sea level is rising due to human caused global warming in two equally important ways: Melting ice and thermal expansion.

Glaciers worldwide and the last two remaining ice sheets (Greenland and Antarctica) are rapidly melting, which adds water to the ocean. Additionally, since the ocean has warmed 0.7℃ the water is expanding, taking up more room. Together these two processes are causing sea level to rise about 3mm/year, which is a rate that is unprecedented over the past 2,500-plus years. This may not seem like a lot per year, but high-tide flooding is now 300% to more than 900% more frequent than it was 50 years ago.