Click link to expand for a text description of figure 3.2
This is a cyclic flow chart describing how people interact with the climate system.
- "Climate change" leads to "impacts of climate change".
- "Impacts of climate change" lead to "responses to climate change".
- "Responses to climate change" either leads back to
- "impacts of climate change" (labeled as "Adaptation") or
- "causes of climate change" (labeled mitigation).
- "Causes of climate change" leads back to climate change.
The impacts of climate change denote a change in a system caused by its exposure to climate change. Impacts can be positive or negative in the same systems in the same places. For instance, considering the natural and human systems found in areas with cold winters and considerable ice and snow, a positive impact of climate change is the reduction in auto accidents resulting from decreasing ice and snow on roadways during winter. A negative impact is the shrinking of water supplies caused by reduced snow packs and glaciers.
Many natural and human systems feel the impacts of climate change. Natural systems experiencing climate impacts include hydrologic systems, cryospheric systems, geomorphic systems, and ecosystems (i.e., the natural components of the climate system studied in Lesson 1). Human systems facing climate change impacts include water resources, health systems, and settlements, among many others. Often, natural and human systems both come under pressure from climate change at the same time and place. For example, in coastal zones, rising sea levels, escalating water temperatures, more frequent and intense storms, and other changes are affecting natural systems and human systems simultaneously.
The severity of negative impacts depends on the vulnerability of the system. Vulnerability itself depends on the exposure of the system to the climate change, the sensitivity of the system to that exposure, and the ability of the system to respond and reduce its exposure or sensitivity. Returning to coastal zones, islands in many subtropical locations are exposed to hurricanes, and one of the most devastating aspects of a hurricane is storm surge flooding. As sea level rises, storm surges penetrate further inland, exposing larger areas, more ecosystems, more people, and more infrastructure to flooding. The more vulnerable coastal zones—that is, those coasts where impacts will worsen as climate change progresses—are either more exposed or more sensitive to storm surges or are unable to reduce their exposure or sensitivity.