The potential occurrence of a natural or human-induced physical event or trend or physical impact that may cause loss of life, injury, or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems, and environmental resources. Source:


Variable (e.g., temperature or rainfall) or combination of variables that is representative of the state of a system. For example, the amount of rainfall and evaporation are important factors in the drought indicator. Source:

Land surface air temperature

The near-surface air temperature over land, typically measured at 1.25–2 m above the ground using standard meteorological equipment. Source:

Naturalized streamflow

Streamflow simulated under the assumption of no human-induced changes, i.e. no impoundment of water in reservoirs nor water abstractions for human water use.

Net irrigation requirement

The mean amount of water that is additionally evapotranspirated due to irrigation if enough water can be supplied to allow for optimal irrigation.


A percentile is a value on a scale of 100 that indicates the percentage of the data set values that is equal to or below it. The percentile is often used to estimate the extremes of a distribution. For example, the 90th (10th) percentile may be used to refer to the threshold for the upper …

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Precipitation is the sum of rainfall and snowfall. Source:


A projection is a potential future evolution of a quantity or set of quantities, often computed with the aid of a model. Unlike predictions, projections are conditional on assumptions concerning, for example, future socio-economic and technological developments that may or may not be realized. Source:


One pathway where radiative forcing peaks at approximately 3 W m-2 before 2100 and then declines. Source: