A growing number of companies are opening their books on climate risks, greenhouse gas emissions and environmental strategies. But are businesses genuinely improving their climate disclosures, or are industry-wide statistics telling an incomplete story? A new study from Kyushu University suggests that headline averages may be concealing substantial progress among companies with a long history of environmental reporting.

Published in Corporate Social Responsibility and Environmental Management on 14 October 2026, the study examined a decade of climate disclosure scores from CDP, formerly the Carbon Disclosure Project. The international non-profit organisation evaluates corporate environmental reporting, including emissions, climate risks and governance. Researchers found that companies assessed consistently between 2016 and 2025 made considerably greater gains than overall averages indicated, largely because expanding participation brought lower-scoring newcomers into the rankings.

“While average scores give us a broad picture of reporting trends, the companies being assessed change over time, which can mask progress within individual companies,” explains Associate Professor Alexander Ryota Keeley of Kyushu University’s Faculty of Engineering. His team analysed CDP climate scores for 8,959 companies, representing 37,450 company-year observations, and distinguished long-term participants from companies entering or leaving the assessments.

The difference was striking. Converting CDP’s eight letter grades into a numerical scale, researchers found that the overall average rose just 0.42 points, from 5.04 in 2016 to 5.46 in 2025. Yet the 1,470 companies assessed in both years improved by 1.12 points, climbing from 5.24 to 6.36. That represents nearly three times the improvement suggested by the headline average.

The researchers traced this discrepancy to changes in the companies being evaluated. New entrants, whose scores generally lagged behind those of established participants, reduced the overall increase by 0.90 points. Meanwhile, the departure of lower-scoring companies added 0.20 points, leaving a net reduction of 0.70 points. In effect, the changing pool of participants concealed much of the progress made by consistent reporters.

The study also examined the quality of written climate disclosures in 2024–2025. Researchers developed a Textual Detail Index measuring response length, numerical information and cautious wording. More detailed responses were associated with higher CDP scores, suggesting that reporting depth matters alongside formal governance structures. The team now hopes to extend its analysis to water and forest disclosures, combining datasets to reveal broader connections between corporate environmental performance and social impacts.

For investors and businesses, the findings offer a warning against relying too heavily on headline rankings. “Looking beyond the averages to companies’ governance and long-term commitments can help reveal where progress is being made and where challenges remain,” says Keeley. As climate reporting expands worldwide, tracking the same companies over time may provide a clearer picture of genuine progress.

More information: Alexander Ryota Keeley et al, The Hidden Arithmetic of Climate Disclosure: How a Decade of CDP Climate Scores Masks a Large Within-Firm Rise and an Equally Large Composition Drag, Corporate Social Responsibility and Environmental Management. DOI: 10.1002/csr.71080

Journal information: Corporate Social Responsibility and Environmental Management Provided by Kyushu University