Greenhouse gases in the atmosphere behave in much the same way as the blanket and is responsible for an elevated temperature over the earth's surface. From this, one may gather that greenhouse gases are in effect beneficial to life on earth. In fact they are. It is when their concentrations are no longer in equilibrium as a result of excessive GHG input that problems arise. Of particular concern in this situation would be the behaviour of our oceans.
Seawater expands in volume with increasing temperature.
This in turn would lead to rising sea levels. The rise in temperature will influence the melting of glaciers and sea ice trapped in Polar Regions and we can expect rising sea levels to be exacerbated even further. Estuarine areas, including wetlands, will be at risk through submersion from possible innundation. Increasing sea levels are also expected to threaten our fresh water supplies as more saltwater intrudes into exposed aquifers. Small island states of low elevation will be in danger of losing valuable land space or of disappearing altogether.