Different organizations define adaptation differently, but they all revolve around taking some action to reduce vulnerability to changes in the climate - real or anticipated. Here are some definitions:
“Adaptation refers to adjustments in ecological, social, or economic systems in response to actual or expected climatic stimuli and their effects or impacts. It refers to changes in processes, practices, and structures to moderate potential damages or to benefit from opportunities associated with climate change.” (The United Nations Framework Convention on Climate Change)
“The process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects.” (The International Panel on Climate Change, or IPCC, p. 5)
“Adjustment or preparation of natural or human systems to a new or changing environment which moderates harm or exploits beneficial opportunities.” (U.S. Environmental Protection Agency)
“Adaptation consists of actions undertaken to reduce the adverse consequences of climate change, as well as to harness any beneficial opportunities. Adaptation actions aim to reduce the impacts of climate stresses on human and natural systems.” (Australia’s National Climate Change Adaptation Research Facility)
Adaptation overlaps but differs from resilience, another byword. Here are some definitions for resilience:
“The ability of people, households, communities, countries, and systems to mitigate, adapt to, and recover from shocks and stresses in a manner that reduces chronic vulnerability and facilitates inclusive growth.” (U.S. State Department)
“The capacity of social, economic, and environmental systems to cope with a hazardous event or trend or disturbance, responding or reorganizing in ways that maintain their essential function, identity, and structure, while also maintaining the capacity for adaptation, learning, and transformation.” (The International Panel on Climate Change, or IPCC, p. 5)
“A capability to anticipate, prepare for, respond to, and recover from significant multi-hazard threats with minimum damage to social well-being, the economy, and the environment.” (U.S. Environmental Protection Agency)