Episode Details

In some coastal cities, ordinary high tide on a clear, calm, cloudless day is now enough to send seawater bubbling up through the drains and into the streets, with no storm in sight at all. This episode explains what's really driving global sea level rise, from the warming ocean simply expanding to ice sheets and glaciers adding new water, why melting sea ice doesn't raise sea level at all but melting land ice does, the surprising "gravitational fingerprint" left by shrinking ice sheets, why some coastlines are sinking or rising independently of the ocean itself, how scientists actually measure sea level with tide gauges and satellites, and why future sea level rise is discussed in honest ranges rather than single confident numbers.

You'll come away understanding the two main physical causes of global sea level rise, why floating sea ice melting doesn't change sea level but melting glaciers and ice sheets does, what a gravitational sea level fingerprint is, why land can be sinking or rising independently of the ocean, how tide gauges and satellite altimetry are used together to track sea level, why local sea level trends can differ dramatically from the global average, and why genuine scientific uncertainty about future rates isn't the same thing as doubt that sea level is rising.

Talking Science is sponsored by Kinsoft. Visit www.kinsoft.com.au

Further reading: NASA – sea level change portal and satellite altimetry data; NOAA – tide gauge records and sea level trend reports; IPCC – Sixth Assessment Report chapters on sea level and the cryosphere; CSIRO – Australian sea level research and coastal monitoring.