Temperature Extremes
In many cases, a weather or climate event with a high impact
A marked unusual hot weather (Max, Min and daily average) over a region persisting at least two consecutive days during the hot period of the year based on local climatological conditions, with thermal conditions recorded above given thresholds (WMO 2016).
![Pooling on sea ice (indicating warming) © Photo: NASA, Jeremy Harbeck Pooling on sea ice (indicating warming)](/site/assets/files/8762/sea_ice_nasa_jeremy_harbeck.600x600.jpg)
Pooling on sea ice (indicating warming)
Photo: NASA, Jeremy Harbeck
Photo: NASA, Jeremy Harbeck
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Monitoring ecosystem impacts of the extreme event | Description of extreme event | Detecting and monitoring the extreme event itself |   | |||||||||
Name | Suggested background data needed to assess impact on ecosystem/biodiversity (if any)* | Suggested method to monitor impacts of extreme event (if different from or background data are missing) | Expected temporal scale of impact | Priority FECs to monitor | Description | Expected temporal scale of extreme event itself | Expected spatial scale of extreme event itself | Types of impact (and relevant cascading effects) | Definition of extreme event (see also Definition-sheet) | Variable to detect extreme event | Method to monitor (risk of) extreme event itself (if different from detection method) | Reference/Links |
Cold waves / spells | Diversity, abundance, composition, productivity, phenology, spatial structure, ecosystem functions and processes, phenology, demographics, temporal cycles and health for flora and fauna | < 5 years | A marked and unusual cold weather characterized by a sharp and significant drop of air temperatures near the surface persisting at least two consecutive days | Brief (< month) | Large (region/ > 10 km2) | Impact on terrestrial ecosystem - coverage/abundance, survival and reproduction of flora and fauna from suboptimal conditions | Minimal 1, 5 or 10th percentile of Tmin of the time of year | Air temperature measurements | ||||
Heat waves / spells | Diversity, abundance, composition, productivity, phenology, spatial structure, ecosystem functions and processes, phenology, demographics, temporal cycles and health for flora and fauna | < 5 years | A marked unusual hot weather persisting at least two consecutive days or a persistent period of abnormal warm weather | Brief (< month) | Large (region/ > 10 km2) | Impact on terrestrial ecosystem - coverage/abundance, survival and reproduction of flora and fauna from suboptimal conditions | Top 1, 5 or 10th percentile of Tmax of the time of year | Air temperature measurements |