The 4th IPCC assessment projected that without further acceleration of the dynamic contribution from the Greenland and Antarctic ice sheets 21st century sea-level rise will be in the range of approximately 20 to 60cm. They also stated that increases in this dynamic contribution could lead to a larger total sea-level rise but that there was insufficient information to provide an upper limit at that time. The current situation is that there is mixed evidence on the issue of whether sea-level rise will exceed the IPCC range. We can not rule out sea level increases of up to around 2m, but such large rises are currently considered to have a low probability.
A growing number of projections use an empirical technique, which tends to predict higher sea level rise in the 21st century, but these methods do not contain detailed physics and their results may be unreliable. In view of this uncertainty our recommendations are:
- Monitoring of sea level should continue
- Physical model improvements are a scientific priority, especially ice sheet processes We also suggest that a UK sea level expert panel is established and meets once per year in order to provide an updated interpretation of the science of sea level and the latest projections.