Table 1.
Overview of definitions of ECEs proposed in the literature. The column ‘type’ describes whether a definition takes a purely climatological perspective or also includes aspects of the impact of climate. The last column specifies whether a definition requires a climatic event to have a specific biological impact (see also §2c).
| source | definition | type | specifies impacts? |
|---|---|---|---|
| IPCC 2012 [4] | the occurrence of a value of a weather or climate variable above (or below) a threshold value near the upper (or lower) ends of the range of observed values of the variable (typically 5% or 10%) | climatological | no |
| NAS 2016 [1] | a weather or climate event that is rare at a particular place (and, sometimes, time of year). […] Definitions of rare vary, but an extreme weather event would normally be […] rarer than a particular percentile (e.g. 1st, 10th, 90th, 99th) of a probability density function estimated from observations expressed as departures from daily or monthly means | climatological | no |
| Jentsch et al. 2007 [12] | climatic extremes that have a strong abruptness (i.e. biological magnitude over biological duration) | impact-related | no |
| Bailey & van de Pol 2016 [10] | an episode where climate or climate-driven conditions trigger a negative threshold-like (nonlinear) biological response | impact-related | no |
| This study | climatic conditions that cause the (biological) response to be in the e.g. 5% of most extreme values of the (biological) response variable | impact-related | no |
| Smith 2011 [13] | an episode in which a statistically unusual or rare climatic period alters ecosystem structure and/or function well outside the bounds of what is considered typical or normal variability | impact-related | yes, ecosystem structure |
| Gutschik & BassiriRad 2003 [11] | an event during which the acclimatory capacity of an organism is substantially exceeded (i.e. a long return time or hysteresis) | impact-related | yes, hysteresis |
| Wingfield et al. 2017 [20] | climate causes the cumulative resources available to an individual to be exceeded by the sum of its energetic costs. This allostatic overload triggers the emergency life-history stage that temporarily allows the individual to cease regular activities in an attempt to survive the extreme conditions | impact-related | yes, allostatic overload |