Sea Level

Sea Level Rise

The systematic warming of the planet is directly causing global mean sea level to rise in two primary ways: (1) mountain glaciers and polar ice sheets are increasingly melting and adding water to the ocean, and (2) the warming of the water in the oceans leads to an expansion and thus increased volume. Global mean sea level has risen approximately 210–240 millimeters (mm) since 1880, with about a third coming in just the last two and a half decades. Currently, the annual rise is approximately 3mm per year. Regional variations exist due to natural variability in regional winds and ocean currents, which can occur over periods of days to months or even decades. But locally other factors can also play an important role, such as uplift (e.g. continued rebound from Ice Age glacier weight) or subsidence of the ground, changes in water tables due to water extraction or other water management, and even due to the effects from local erosion.

Rising sea levels create not only stress on the physical coastline, but also on coastal ecosystems. Saltwater intrusions can be contaminating freshwater aquifers, many of which sustain municipal and agricultural water supplies and natural ecosystems. As global temperatures continue to warm, sea level will keep rising for a long time because there is a substantial lag to reaching an equilibrium. The magnitude of the rise will depend strongly on the rate of future carbon dioxide emissions and future global warming, and the speed might increasingly depend on the rate of glacier and ice sheet melting.

This page supports the exploration of our changing seas through analysis of Historical Sea Surface Temperatures, as well as Historical (satellite measured) Sea Level Anomalies and Future Sea Level Rise Projections (model-based). Sea Surface Temperature and Sea Level Anomaly data was produced as part of the European Space Agency's Sea Level Climate Change Initiative and is presented at 0.25 x 0.25 degree resolution. Sea Level Rise data was derived from the CMIP5 collection and is presented as 1 x 1 degree resolution. 

Use the Dropdown box to select a variable and the toggle underneath the map to change time periods.