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• Some types of weather affect Americans' belief that they have experienced global warming. • Americans associate hot, dry days and extreme drought with global warming. • People often fail to interpret extreme rainfall or flooding as due to global warming. Public perceptions of climate change in the United States are deeply rooted in cultural values and political identities. Yet, as the public experiences extreme weather and other climate change-related impacts, their perceptions of the issue may shift. Here, we explore whether, when, and where local climate trends have already influenced perceived experiences of global warming in the United States. Using a large national survey dataset (n = 13,607), we compare Americans' experiences of climate with corresponding trends in seven different high-resolution climate indicators for the period 2008 to 2015. We find that increases in hot dry day exposure significantly increases individuals' perceptions that they have personally experienced global warming. We do not find robust evidence that other precipitation and temperature anomalies have had a similar effect. We also use multilevel modeling to explore county-level patterns of perceived experiences with climate change. Whereas the individual-level analysis describes a likely causal relationship between a changing climate and individuals' perceived experience, the multilevel model depicts county-level changes in perceived experience resulting from particular climate trends. Overall, we find that exposure to hot dry days, has a modest influence on perceived experience, independent of the political and socio-demographic factors that dominate U.S. climate opinions today. [ABSTRACT FROM AUTHOR]

Globally, biodiversity is declining, and a major driver of this decline is climate change; consequently, we need ways to evaluate the vulnerability of species to this change. We assessed 25 species of herpetofauna (7 amphibians and 18 reptiles) using multi-model averaging of NatureServe's Climate Change Vulnerability Index (CCVI), a qualitative trait-based vulnerability assessment tool. We calculated vulnerability across model runs varying type and extent of spatial data and climate model scenario. Amphibians were more vulnerable than reptiles. The most vulnerable species were those that were dependent on water for their habitat, high elevation species, and habitat specialists. For reptiles in particular, the projected downscaled extent of temperature change and change in moisture availability were also important in delineating vulnerability. Unfortunately, the invasive American Bullfrog was less vulnerable than any of the native amphibians, which highlights the importance of considering invasives when planning for climate change. Snakes that were riparian specialists also were ranked as highly vulnerable. Lizards were ranked as less vulnerable related to projected differences in the proportion of their range experiencing larger changes in temperature. We suggest improvements to the CCVI vulnerability index. For example, certain aspects of reptile biology that are critical to climate-related vulnerability are not included in the current generation of the Climate Change Vulnerability Index, specifically reproductive strategy and the difference in vulnerability between viviparous and oviparous species. Methods for assessing vulnerability will need continued refinement as we contend with climate change and other human-caused factors that are driving the biodiversity crisis. [ABSTRACT FROM AUTHOR]