California Climate Change Glossary

Letter I

Ice Core. A cylindrical section of ice removed from a glacier or an ice sheet in order to study climate patterns of the past. By performing chemical analyses on the air trapped in the ice, scientists can estimate the percentage of carbon dioxide and other trace gases in the atmosphere at that time. (EPA)

IMAGE Model. The Integrated Model for Assessment of the Greenhouse Effect. This is one of the climate models applied for the construction of the IPCC SRES scenarios. (Lenn)

Indirect Aerosol Effect. Aerosols may lead to an indirect radiative forcing of the climate system through acting as condensation nuclei or modifying the optical properties and lifetime of clouds. (Lenn)

Industrial Revolution. The complex of radical socioeconomic changes starting in the early 18th century. Extensive mechanization of production systems resulted in a shift from home-based hand manufacturing to large-scale factory production. The industrial revolution marks the beginning of a strong increase in the use of fossil fuels resulting in an increase in greenhouse gases in the atmosphere and therefore contributed to the enhanced greenhouse effect. (Lenn)

Infra-red Radiation. The heat energy that is emitted from all solids, liquids, and gases. In the context of the greenhouse issue, the term refers to the heat energy emitted by the Earth's surface and its atmosphere. Greenhouse gases strongly absorb this radiation in the Earth's atmosphere, and reradiate some back towards the surface, creating the greenhouse effect. (EPA)

Instrumental Period. Period after 1855 that allowed us to reconstruct temperatures because thermometers were producing reconstructable data. Before 1855 proxy indicators were used to determine temperatures. (Lenn)

Integrated Assessment. A method of analysis that combines results and models from the physical, biological, economic and social sciences, and the interactions between these components, in a consistent framework, to project the consequences of climate change and the policy responses to it. (IPCC)

Integrated Environmental Assessment. The work field that researches causes and impacts of environmental issues and policy measures (solutions) by combining economic, environmental and social sciences. It is a subdivision of the work field of Environmental Systems Analysis. This is a type of Environmental Science that applies many different tools, including environmental models, environmental impact assessment and environmental indicators, to describe and find solutions for environmental problems. (Lenn)

Intergovernmental Panel on Climate Change. The IPCC was established jointly by the United Nations Environment Programme and the World Meteorological Organization in 1988. The purpose of the IPCC is to assess information in the scientific and technical literature related to all significant components of the issue of climate change. The IPCC draws upon hundreds of the world's expert scientists as authors and thousands as expert reviewers. Leading experts on climate change and environmental, social, and economic sciences from some 60 nations have helped the IPCC to prepare periodic assessments of the scientific underpinnings for understanding global climate change and its consequences. With its capacity for reporting on climate change, its consequences, and the viability of adaptation and mitigation measures, the IPCC is also looked to as the official advisory body to the world's governments on the state of the science of the climate change issue. For example, the IPCC organized the development of internationally accepted methods for conducting national greenhouse gas emission inventories. (IPCC)

International Emissions Trading. Article 17 of the Kyoto Protocol allows developed countries to participate in emissions trading for the purposes of meeting their assigned amounts. (Australia)

Inverse Modeling. Modeling technique by which modeling input is estimated from modeling output, rather than vice versa. This is for example used to determine the causes of enhanced greenhouse gas concentrations in the atmosphere and for computing atmospheric transport. (Lenn)

IPCC SRES Scenarios.Special Reports on Emission scenarios by the IPCC, containing information on possible future climate developments and consequences for society and the environment. Emissions scenarios are a central component of any assessment of climate change. See for more information the Lenntech IPCC SRES scenarios page. (Lenn)