The Seas Will Keep Rising, Even If the Planet Cools

Even if global temperatures go above 1.5°C and then come back down, sea levels will keep rising for centuries. That is the main message of Sea Level Rise Under Overshoot, a new report from the NASA Sea Level Change Team (N-SLCT).

The report delivers information on the future of sea level rise connected to temperature overshoot pathways, following the framework of UNEP's Limiting Overshoot: Navigating Exceedance of 1.5°C and Pathways Towards Return. The report discusses how the ocean will react to warming from decades to centuries. In a scenario where the temperature of the planet comes down quickly, sea level will not follow for centuries to come.

Key findings

• Sea level rise is speeding up. The rate of rise has more than doubled since 1993, and global sea level has risen more than 10 centimeters.
• The next 30 years are locked in. Another 10 to 15 centimeters of global rise is expected by 2050, whatever path emissions take.
• Long term choices still matter. After 2050, how high temperatures peak and how long they stay there will decide how much more the seas rise.
• Impacts are already here. Coastal flooding is increasing around the world, and low lying island nations are on the front line.

Our contribution

The N-SLCT led the report and built it on more than 30 years of NASA satellite observations of sea level. That record gives an independent check on climate models and shows clearly how much the seas will rise in the coming decades.

The report also continues the team's work with Pacific Island nations. It builds on earlier N-SLCT sea level assessments for Tuvalu and Kiribati to show what the rise already locked in means for Pacific communities and other small island states. Throughout the process, the team worked with the Rising Nations Initiative and received feedback from UN Member States through the Coalition for addressing Sea Level Rise and Its Existential Threats (C-SET). The goal is to put NASA science directly in the hands of the nations facing sea level rise first.

Watch the animation for the key findings, and read the full report using the link in the sidebar.