Global sea levels are rising faster and faster. It spells catastrophe for coastal towns and cities.

For around 2,000 years, global sea levels varied little. That changed in the 20th century. They started rising and have not stopped since — and the pace is accelerating.

Scientists are scrambling to understand what this means for the future just as President Trump strips back agencies tasked with monitoring the oceans.

Since 1993, satellites have kept careful watch over the world’s oceans, allowing scientists a clear view of how they are behaving. What they have revealed is alarming.