Sea levels are rising faster than expected. In 2007 the IPCC report predicted a rise of between 0.2 and 0.5 meters by the year 2100 but sea levels are rising much faster. A recent study by University of Colorado geologist Bill Hay suggests that sea level rise may reach one meter by the end of the century. The study has taken into account critical feedbacks which increase the speed that sea level rises. These feedbacks take place in relation to Arctic sea ice, the Greenland ice cap and soil moisture and groundwater mining.
Melting sea ice in itself does not raise the sea-level. However, the reduction of sea ice in the Arctic is playing a key role in the warming of the Arctic, which in turn leads to ice losses in nearby Greenland and over the land areas of northern Canada. Also, when the sea ice melts it reduces the amount of fresh water in the Arctic.
Another factor considered by Hay and his team is the huge store of ice in Greenland and Antarctica which underwent a record-setting melt, speeding up ice streams.
Another feedback which has been considered in the study is the groundwater being mined all over the world to mitigate droughts which ultimately ends up in the oceans.