Explain the features and differences between the icehouse and the greenhouse effect?

The globe can experience periods of warming, such as we are experiencing now in the Quaternary period, or it can experience cooling periods leading to ice ages, such as at the Ordovician-Silurian boundary. An Icehouse planet is characterised by low temperatures, low sea levels, ice caps and glaciers. An increase in snowfall and formation of ice forms a positive feedback loop by increases the albedo of the planets surface, reflecting solar radiation back into space causing a further drop in the global temperature and creating a snow-ball effect. The sea level is lowered as greater volumes of water is stored in the cryosphere (ice and glaciers) than in the ocean. A greenhouse planet is characterised by higher temperatures, higher sea level and the less cryosphere cover. Usually the atmosphere has a high concentration of greenhouse gases such as C02 and methane which act as insulators as they trap solar radiation and reflect it back down to the Earths surface. The rise in temperature decreases the solubility of the ocean which then releases CO2, increasing the 'run-away' greenhouse effect.