With climate change accelerating, and biodiversity declining at a rapid rate, there is an urgent need to understand which species are most vulnerable to prioritize funding for protection, restoration, and mitigation efforts. A recent study co-authored by the National CASC scientists with colleagues from Virginia Tech found that many species’ climate change vulnerability assessments (CCVAs) use only two of the three key elements recommended for use by the Intergovernmental Panel on Climate Change (IPCC): exposure, sensitivity, and adaptive capacity.  

Exposure describes the rate and magnitude of environmental change a species faces; sensitivity reflects their tolerances to those changes, and adaptive capacity refers to their ability to adapt and respond. 

After reviewing 47 CCVA studies on vertebrates conducted between 2008 and 2022, the researchers found that the omission of one of the three factors is often due to data or computational limitations. For example, salamanders are typically hard to find and harder to study, making the collection of comprehensive data especially challenging and time-consuming. In cases where two factors already indicate vulnerability, researchers often move forward with the CCVA without the third factor to avoid delaying important actions – making time a critical fourth consideration. 

Though three-factor CCVAs are ideal, a two-factor approach can still help researchers evaluate a species’ vulnerability and guide timely conservation action while possibly expanding assessments across more species and regions. 

This research was funded by the National CASC Project titled “Developing an Indicator of Species Vulnerability to Climate Change to Support a Consistent Nationwide Approach to Assessing Vulnerability.”