Short answers, pulled from the story.
Climate change vulnerability is the propensity or predisposition to be adversely affected by climate change. The Third IPCC report (2001) defined it as the degree to which a system is susceptible to, and unable to cope with, adverse effects of climate change, including climate variability and extremes. It applies to both people and ecosystems, and it is considered a component of climate risk.
As of 2021, approximately 3.3 to 3.6 billion people were estimated to live in contexts that are highly vulnerable to climate change.
People with low incomes, indigenous peoples, women, children, the elderly, outdoor workers, and people with pre-existing health conditions are consistently identified as more vulnerable. A report in The Lancet found these groups bear the greatest health impacts from climate change.
During the 2006 heat wave in Los Angeles, California, the mortality rate among African American populations was double that of the average population. Heat-related emergency department visits also increased significantly among African American and Asian and Pacific Islander communities.
Small Island Developing States face heightened vulnerability because climate change drives more frequent and intense hurricanes, typhoons, and cyclones. Their adaptive capacity is limited in part by low GDP and high costs of adaptation relative to national income.
Global tools include the ND-GAIN Country Index, the INFORM Risk Index, and the WorldRiskIndex. Sub-national and local assessments use approaches such as the Vulnerability Sourcebook, the WEAP water resource model, and spatial mapping. A 2019 systematic review identified 84 studies using mapping specifically to communicate and analyze climate vulnerability.