Sea level rise is a natural consequence of the warming of our planet. We know this from basic physics. When water heats up, it expands. So when the ocean warms, sea level rises. When ice is exposed to heat, it melts. And when ice on land melts and water runs into the ocean, sea level rises. For thousands of years, sea level has remained relatively stable and human communities have settled along the planet’s coastlines. But now Earth’s seas are rising. Globally, sea level has risen about eight inches since the beginning of the 20th century and more than two inches in the last 20 years alone. All signs suggest that this rise is accelerating. Read more: <a href="http://go.nasa.gov/1heZn29" rel="nofollow">go.nasa.gov/1heZn29</a> Caption: An iceberg floats in Disko Bay, near Ilulissat, Greenland, on July 24, 2015. The massive Greenland ice sheet is shedding about 300 gigatons of ice a year into the ocean, making it the single largest source of sea level rise from melting ice. Credits: NASA/Saskia Madlener <b><a href="http://www.nasa.gov/audience/formedia/features/MP_Photo_Guidelines.html" rel="nofollow">NASA image use policy.</a></b> <b><a href="http://www.nasa.gov/centers/goddard/home/index.html" rel="nofollow">NASA Goddard Space Flight Center</a></b> enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. <b>Follow us on <a href="http://twitter.com/NASAGoddardPix" rel="nofollow">Twitter</a></b> <b>Like us on <a href="http://www.facebook.com/pages/Greenbelt-MD/NASA-Goddard/395013845897?ref=tsd" rel="nofollow">Facebook</a></b> <b>Find us on <a href="http://instagrid.me/nasagoddard/?vm=grid" rel="nofollow">Instagram</a></b>

This graph shows the rise in global mean sea level from 1993 to 2024 based on data from a series of five international satellites. The solid red line indicates the trajectory of this increase, which has more than doubled over the three decades. The dotted red line projects future sea level rise. Global sea level rose faster than expected in 2024 due mostly to ocean water expanding as it warms, or thermal expansion. According to a NASA-led analysis, last year's rate of rise was 0.23 inches (0.59 centimeters) per year, compared to the expected rate of 0.17 inches (0.43 centimeters) per year. In recent years, about two-thirds of sea level rise was due to the addition of water from land into the ocean by melting ice sheets and glaciers. About a third came from thermal expansion of seawater. But in 2024, those contributions flipped, with two-thirds of sea level rise coming from thermal expansion. This NASA-led analysis is based on a sea level dataset featuring more than 30 years of satellite observations, starting with the U.S.-French TOPEX/Poseidon mission, which launched in 1992. The Sentinel-6 Michael Freilich mission, which launched in November 2020, is the latest in the series of satellites that have contributed to this sea level record. https://photojournal.jpl.nasa.gov/catalog/PIA26189

The PREFIRE (Polar Radiant Energy in the Far-InfraRed Experiment) mission will send two CubeSats – shown as an artist's concept against an image of Earth from orbit – into space to study how much heat the planet absorbs and emits from its polar regions, including the Arctic and Antarctica. Analysis of PREFIRE measurements will inform climate and ice models, providing better projections of how a warming world will affect sea ice loss, ice sheet melt, and sea level rise. Improving climate models can ultimately help to provide more accurate projections on the impacts of storm severity and frequency, as well as coastal erosion and flooding. The mission consists of two 6U CubeSats with a baseline mission length of 10 months and is jointly developed by NASA and the University of Wisconsin-Madison. NASA's Jet Propulsion Laboratory in Southern California manages the mission for the agency's Science Mission Directorate and is providing the instruments. Blue Canyon Technologies is building the CubeSats, and the University of Wisconsin-Madison will process the data collected by the instruments. The science team includes members from JPL and the Universities of Wisconsin, Michigan, and Colorado. https://photojournal.jpl.nasa.gov/catalog/PIA25778

The recently launched Surface Water and Ocean Topography (SWOT) mission collected data on sea levels around two of the inhabited islands of Tuvalu, a nation in the South Pacific Ocean that has been threatened with sea level rise that substantially exceeds the global average. The image shows two areas of red that indicate higher than normal sea levels around two of Tuvalu's inhabited islands, Nanumanga and Nanumea. The higher sea levels were likely caused by internal tides or circular currents called eddies. The SWOT data illuminates for the first time these small ocean features that, when they occur on top of rising sea levels, can lead to episodic flooding along coastlines. The Tuvalu data was collected March 21, 2023. Rising seas are a direct consequence of climate change. On a global scale, the combination of warming ocean waters and ice melt from glaciers and ice sheets is leading to sea level rise that is occurring at an ever-increasing rate. The current rate of rise is more than 0.15 inches (4 millimeters) per year, an increase from 0.08 inches (2 millimeters) per year in 1993. This seemingly small increase holds great significance for coastal communities that have seen more than a century of persistent sea level rise. The gap between the average high tide and flooding conditions has narrowed, and coastal impacts driven by sea level rise have increased in frequency and severity in recent years. This is particularly true for low-lying island nations like Tuvalu, located about 620 miles (1,000 kilometers) north of Fiji. Sea level rise does not occur at the same rate everywhere across the globe, and can be exacerbated by natural ocean fluctuations that occur over time periods from years to decades. For Tuvalu, the amount of sea level rise has been substantially higher than the global average over the past three decades. The amount of rise, when coupled with Tuvalu's low land elevations, places the country increasingly under threat. In the near term, sea level rise will combine with naturally occurring ocean variability and storms to exacerbate events like coastal flooding. Monitoring and understanding sea level change is critical for Tuvalu and other low-lying island nations. Launched on Dec. 16, 2022, from Vandenberg Space Force Base in central California, SWOT collected the Tuvalu sea level data during a period of commissioning, calibration, and validation. Engineers are checking out the performance of the satellite's systems and science instruments before the planned start of science operations in summer 2023. https://photojournal.jpl.nasa.gov/catalog/PIA25777