Earth is losing land to the ocean—faster than expected. According to a new study published in Proceedings of the National Academy of Sciences, global mean sea level has climbed roughly 3.5 inches since 1993. Even more concerning, the pace has accelerated sharply in the past two decades. About 60% of this rise comes from added water mass, and more than four-fifths of that added mass originates from melting land ice.

Sea levels change for two main reasons: warming seawater expands, and water from melting ice flows into the ocean. The new findings come from satellite laser ranging (SLR), a system where ground stations fire laser pulses at satellites and measure the time it takes for the light to return—accurate to the millimeter. These tiny shifts reveal changes in Earth’s gravity as water and ice move around the planet. When compared with NASA’s GRACE satellite data, both methods showed the same result: the oceans are gaining mass, and quickly.

‍

The laser record fills a crucial gap. GRACE data begins in 2002, but SLR extends back to the early 1990s, providing a continuous, independent look at how much water is being added to the oceans. When this mass data is combined with satellite altimetry, which measures sea surface height, the numbers line up almost perfectly. Together, they confirm the full sea level “budget”: heat expansion plus added water equals the total rise measured globally.

‍

Three and a half inches may not sound like much, but those few inches sit beneath every wave, tide, and storm surge. In coastal cities around the world, what used to be rare “high-tide floods” now happen several times a year. Added water mass also alters local gravity and tilts the sea surface slightly, making sea level rise uneven across regions. The acceleration seen today matches faster ice loss in Greenland and Antarctica—evidence that the trend is not slowing down.