Global Warming Potential (GWP)
An index (i.e., a relative measure) of how much heat a greenhouse gas traps in the atmosphere over a chosen time horizon, relative to that of carbon dioxide. The GWP represents the combined effect of the differing times these gases remain in the atmosphere and their relative effectiveness in absorbing outgoing thermal infrared radiation. Although the most common time horizon is 100 years, GWP have been reported also for time horizons of 20 years and 500 years.
Greenhouse Gas (GHG)
Any of the atmospheric gases, both natural and anthropogenic, that contribute to the greenhouse effect by absorbing infrared radiation produced by solar warming of the Earth's surface. Water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2) and ozone (O3) are the primary greenhouse gases in the atmosphere.
Greenhouse Gas Effect
Heat trapping effect of greenhouse gases in the troposphere (lowest portion of the earth's atmosphere)
Life Cycle Assessment
LCA addresses the environmental aspects and potential environmental impacts (e.g. use of resources and the environmental consequences of releases) throughout a product's life cycle from raw material acquisition through production, use, end-of-life treatment, recycling and final disposal (i.e. cradle-to-grave). There are four phases in an LCA study: a) the goal and scope definition phase, b) the inventory analysis phase, c) the impact assessment phase, and d) the interpretation phase (ISO 2006).
Narrowly defined, SI refers to increase food production from existing farmland in ways that place far less pressure on the environment and that do not undermine our capacity to continue producing food in the future. However, Garnett et al. (2013) added the following four premises underlying SI: (a) The need to increase production; (b) Increase production must be met through higher yields because increasing the area of land in agriculture carries major environmental costs; (c) Food security requires as much attention to increasing environmental sustainability as to raising productivity; and (d) SI denotes a goal but does not specify a priori how it should be attained or which agricultural techniques to deploy.