Sea Level Rise Projections

Sea level rise could reach 0.3 to over 2 meters by 2100, a 6-fold uncertainty that carries existential stakes for 600 million coastal residents. The current rate—3.6 mm per year through 2024—already accelerates 25% faster than the average of historic IPCC projections, driven partly by Greenland ice sheet dynamics. While #1 Arctic ice-free summers threaten albedo feedback, sea level rise delivers irreversible coastal inundation, with every centimeter increasing storm surge exposure for 2 million people worldwide. Thermal expansion accounts for 50% of observed rise to date, but future contributions from Antarctic ice shelves could double that share. Unlike the Amazon's tipping point, this effect offers no climate feedback that could reverse the trend—only adaptation or mitigation matter.