As seas warm and ice melts, Earth's oceans have risen steadily.
Now scientists say sea level rise is accelerating, according to a new study based on NASA data.
In the past 25 years, sea level is not only rising, but the rate of that rise is getting faster.
Increased ice melting in Greenland and Antarctica is primarily responsible for the acceleration.
If this acceleration continues, global sea level could be 26 inches higher by 2100.
Understanding how fast sea level is increasing can help prepare for the effects in coastal areas around the world.