Published by Australian Academy of Science
Glossary | Getting into hot water – global warming and rising sea levels

aquifer. A layer of rock or sand that contains water. For more information see Aquifers (Tasmanian Department of Primary Industries and Water, Australia).

feedback. The process whereby the output of a system affects the input. Positive feedback reinforces or increases something; negative feedback acts to keep a process within certain limits. Positive feedback can work in systems by amplifying a very small effect, changing the previous equilibrium.

greenhouse gas. A gas that is transparent to incoming solar radiation and absorbs some of the longer wavelength infrared radiation (heat) that the Earth radiates back. The result is that some of the heat given off by the planet accumulates, making the surface and the lower atmosphere warmer. For more information see The greenhouse effect (CSIRO Atmospheric Research, Australia).

ice sheet. A very large body of land-based ice. Ice sheets are found in Greenland and Antarctica and are also known as continental glaciers.

Intergovernmental Panel on Climate Change (IPCC). An organisation established in 1988 by the World Meteorological Organization and the United Nations Environment Programme to provide the most widely accepted information available about climate change. The IPCC does not conduct new research or monitor climate-related data, its mandate is to assess existing data and to produce balanced and objective reports. For more information see Intergovernmental Panel on Climate Change (Switzerland).