CLIMATE HAZARDS & CLIMATE RISK

For the purpose of this report, we adopted the Intergovernmental Panel on Climate Change’s (IPCC) definitions of climate hazard and climate risk, seen in Table 1 below.

Term Definition

Climate Hazard

“The potential occurrence of a natural or human-induced physical event or trend 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.”

Climate Risk

“The potential for adverse consequences for human or ecological systems…risks can arise from potential impacts of climate change as well as human responses to climate change. Relevant adverse consequences include those on lives, livelihoods, health and well-being, economic, social and cultural assets and investments, infrastructure, services (including ecosystem services), ecosystems and species.”

Climate risks result from the interaction between climate hazards and the unique vulnerability of the community, human system, or ecological system. Climate hazards become climate risks because of their potential for harm, opening up the opportunity for policies that mitigate risk. Throughout our report, we refer to climate hazards with the intent of highlighting the risks that emerge when climate hazards interact with CDCR’s inadequate policies and inaction.

The specific climate hazards we focus on are extreme heat, extreme cold, flooding, and wildfires. Each climate hazard is described in detail in Table 2.

Term Definition

Extreme Heat

A heat wave, which is “a period of abnormally hot weather, often defined with reference to a relative temperature threshold, lasting from two days to months.”

Extreme Cold

We defined extreme cold using the cold days and cold nights definition Cold days occur when maximum temperature, or nights where “minimum temperature, falls below the 10th percentile, where the respective temperature distributions are generally defined with respect to the 19611990 reference period.”

Flooding

“The overflowing of the normal confines of a stream or other water body, or the accumulation of water over areas that are not normally submerged. Floods can be caused by unusually heavy rain, for example, during storms and cyclones. Floods include river (fluvial) floods, flash floods, urban floods, rain (pluvial) floods, sewer floods, coastal floods, and glacial lake outburst floods (GLOFs).”

Wildfire

“An unplanned fire that burns in a natural area such as a forest, grassland, or prairie. Wildfires are often caused by human activity or a natural phenomenon such as lightning, and they can happen at any time or anywhere.”