Final answer:
The mean rate of retreat for the Norfolk coastline is 2 meters per year, in the context of ongoing global sea level rise. This rate is derived by dividing the total retreat over a decade by the number of years.
Step-by-step explanation:
The norfolk coastline has retreated around 20m over the last 10 years. To calculate its mean rate of retreat, you simply divide the total retreat distance by the number of years. In this case, 20 meters divided by 10 years gives a mean rate of retreat of 2 meters per year. This rate is significant when considering the broader context of sea level rise and its effects on coastal areas.
For instance, since 1880, the sea level has risen about 230 mm, and with current projections, we could see a total rise of 0.5 meters by 2100. This rise of the mean sea level contributes to coastline retreat and increased flooding. Additionally, the effects of global warming are evident in the retreat of glaciers, such as Grinnel Glacier, which have direct impacts on local ecosystems and sea level rise.
Specifically, global sea level is rising at about 1.8 mm per year on average, which can lead to significant changes over decades and centuries.
Understanding these processes is crucial in acknowledging the changes in our structural geography and the importance of environmental conservation and adaptation strategies.