Glossary

Scenarios that temporarily exceed a specific warming limit expressed in global mean temperature increase above pre-industrial levels before bringing the temperature back down again, e.g., by deploying CDR.

The temporary exceedance of a specified level of global warming, such as 1.5°C. Overshoot implies a peak followed by a decline in global warming, achieved through anthropogenic removal of carbon dioxide (CO₂) exceeding remaining CO₂ emissions globally.

Daily maximum temperature of the air near the Earth's surface (approximately 2 metres above the ground).

Annual Mean Temperature during a year where it reaches an extremely low value.

The rarity of such an event (or return period) can be specified: 1-in-10-year, 1-in-20-year, or 1-in-50-year over the reference period of interest (pre-industrial or present-day). The climate risk dashboard provides information on both changes in the intensity of an event of such frequency in the selected reference period over time (quantified in °C in the Timing and Location sections), as well as on changes in the frequency of occurrence of an event at least as extreme over time (quantified in % in the Avoidable vs. Unavoidable section). We refer here to temperature of the air near the Earth’s surface (approximately 2 metres above the ground).

Annual temperature during a year where it equals a median value. We refer here to temperature of the air near the Earth’s surface (approximately 2 metres above the ground). Changes in this indicator are expressed in degrees Celsius (°C).

Annual Mean Temperature during a year where it reaches an extremely high value.

The rarity of such an event (or return period) can be specified: 1-in-10-season, 1-in-20-season, or 1-in-50-season over the reference period of interest (pre-industrial or present-day). The climate risk dashboard provides information on both changes in the intensity of an event of such frequency in the selected reference period over time (quantified in °C in the Timing and Location sections), as well as on changes in the frequency of occurrence of an event at least as extreme over time (quantified in % in the Avoidable vs. Unavoidable section). We refer here to temperature of the air near the Earth’s surface (approximately 2 metres above the ground).

Periods of at least 3 days in which the maximum and minimum temperature exceeds the 90th percentile value of a reference present period (2011-2020).

Daily mean temperature refers to the average temperature of air masses near the Earth’s surface (2 metres above the ground in this case).

The pH scale runs from 0 to 14, with 7 being a neutral pH. Anything higher than 7 is basic (or alkaline) and anything lower than 7 is acidic. The ocean’s average pH is now around 8.1, which is basic (or alkaline), but as the ocean continues to absorb more CO2, the pH decreases and the ocean becomes more acidic.

The subsurface bulk temperature in the top 10m of the ocean in °C. Due to climate change and changes in ocean circulation, warming projected in the global ocean can strongly vary from region to region.

Number of days the selected marine region experiences a heatwave. A marine heatwave is considered to occur if daily mean sea surface temperatures averaged over the top 10m of the ocean exceed values that would be reached only 10% of the time on average in the absence of global warming.

Oxygen concentration dissolved in sea water in the upper 10m (surface) of the ocean in [mg / L].

Low oxygen levels can lead to a decrease in viability and higher mortality in marine ecosystems. Increasing sea water temperatures due to climate change decrease the amount of oxygen that can dissolve in the ocean, thus ocean oxygen levels are currently declining.

Annual average of the maximum temperature reached in a day, measured 2 metres above the ground.

Annual average of the lowest air temperature reached in a day, measured 2 metres above the ground.

Number of days, hours and nights per year where wet bulb globe temperature goes over certain temperatures.

Wet bulb globe temperature (WBGT) is a measure of heat stress in direct sunlight, which takes into account temperature, humidity, wind speed, sun angle and cloud cover (solar radiation). The boundaries that we use below are standards of ISO 7243:2017 'Ergonomics of the thermal environment'. More information on these boundaries can be found in Souverijns et al. 2023.

WBGT > 25°C: Moderate heat stress
WBGT > 28°C: High heat stress
WBGT > 29.5°C: Very high heat stress
WBGT > 31°C: Extreme heat stress