Climate Concern Index (CCI)

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We are pleased to host the Climate Concern Index (CCI) developed by Giovanni Angelini, Maria Elena Bontempi, Luca De Angelis, Paolo Neri and Marco Maria Sorge in "Shocking concerns: public perception about climate change and the macroeconomy".

The index is designed to gauge the intensity and dynamics of people's feelings and interest in climate change, reflecting grassroots engagement with climate issues. The CCI is based on the volume of web searches related to a broad list of disaggregated queries covering topics related to climate change that may generate concern and fear, indicate awareness, and capture people's perceived impact of extreme weather events, natural disasters, environmental risks and policies. Particular attention is paid to the post-cognitive interpretation of affective responses (Van Der Linden, 2014), according to which emotional concern arises after individuals attribute personal experiences to severe climate events, such as heat waves, floods and hurricanes. This distinction reinforces the relevance of the CCI as a measure of endogenous changes in sentiment rather than exogenous physical events.

To assess variations in the perception of climate change between different countries and geographical areas within the same country, the CCI index is available for the United States and Italy, as well as for fifty American states and twenty Italian regions, on a monthly basis since 2004. This disaggregation could indicate differences in the perception of climate concern related to the industrial and cultural context of each part of the country, as well as the impact of specific climate events that have occurred in different areas.

The creation of the CCI begins with a detailed and iterative vocabulary development process, a crucial step in ensuring that the index accurately reflects the diverse dimensions of climate concerns expressed by the general public through web searches. A preliminary list of relevant search terms was initially compiled based on existing literature on climate sentiment. The list was then refined and expanded using prompt engineering techniques to interact with large language models, such as the one underlying OpenAI's ChatGPT chatbot. These models helped identify emerging and contextually relevant terminology used in climate discourse. In parallel, the content of specialized posts on social media and online platforms was examined to validate the real-world relevance of the proposed terms. Many candidate queries that appeared theoretically relevant turned out to be marginal in actual search frequency, while others, less expected, proved to be central to public interest.

After several rounds of testing and validation, we selected a final set of 112 queries focused on the US and 95 focused on Italy. To better structure the index and allow thematic interpretation, the selected were grouped into seven categories reflecting different affective or informational tones:

• natural disasters that generate fear (e.g., "extreme weather", "floods")
• global warming-related threats (e.g., "rising seas", "deforestation")
• broader climate change narratives (e.g., "climate refugees", "climate crisis")
• mitigation and reduction strategies (e.g., "climate solutions", "circular economy")
• technological hope (e.g., "biodiversity", "aquaculture")
• international summits (e.g., "Paris Agreement", "Kyoto Protocol")
• climate or environmental policy terms (e.g., "decarbonization", "IPCC")

The full list of terms for the US is available in Angelini G., Bontempi M. E., De Angelis L., Neri P. and Sorge M. M. (2025) "Shocking concerns: public perception about climate change and the macroeconomy".