How might thermal expansion affect future sea levels?

Answer 1

When things get warm, they expand, and the oceans are no exception. So when the atmosphere gets warmer, as it is now doing, the seas warm as well. Warming seas expand, and the only way they can go is up. So global warming is causing rising sea levels, even without the extra water from melting glaciers and ice caps.

Of course the expansion of the sea with a change in temperature is rather small. The IPCC report predicts an increase of 0.2°C per decade. Also note that global warming is probably raising the temperature of the surface water a bit - but only down to a depth of a few hundred feet, so most of the water in the oceans is not changing temperature noticeably. A change of 0.2°C in ocean water temperature to a depth of 1000 feet would change the volume of the water by 0.00516% thus resulting in an increase of water level of 0..0516 feet (0.62 inches or 1.57 cm). In short, expansion of the ocean water due to global warming could be a minor, but measurable event. Melting ice would be expected to have much more impact.

Answer 2

Thermal expansion occurs when water warms up and expands, causing sea levels to rise. As global temperatures continue to increase, this thermal expansion will contribute to rising sea levels, leading to flooding, coastal erosion, and other challenges for coastal communities. Efforts to mitigate climate change are critical to address the impacts of thermal expansion on future sea levels.