Diplomatic Discourse on Climate Change: A Systemic Functional Analysis of UN Summit Speeches by Major Powers

Abstract

This study examines how major world powers deploy language in diplomatic discourse on climate change, focusing on speeches delivered at United Nations climate summits. Drawing on Halliday’s Systemic Functional Grammar (SFG) and critical discourse analysis (CDA) frameworks, the research adopts a mixed-method approach combining quantitative corpus analysis and qualitative discourse interpretation. A comparative corpus of climate summit speeches by leaders of China, the United States, and the European Union was constructed and analyzed in terms of transitivity patterns, modality use, and evaluative language. The analysis reveals clear differences in linguistic strategies and underlying ideological stances. Chinese speeches emphasize collective action and equity, invoking principles like “common but differentiated responsibilities” and urging multilateral cooperation. U.S. speeches stress urgency and leadership, with frequent use of high-value modal verbs (e.g. must, will) to project commitment and American global leadership. EU leaders consistently frame climate change as an existential crisis demanding immediate collective action, highlighting moral responsibility and Europe’s role as a climate champion. Theoretically, this study enriches SFG-based discourse analysis by comparing cross-cultural diplomatic rhetoric, and it extends CDA research on climate change by revealing how power and ideology shape environmental narratives. Practically, the findings offer insights for international climate communication, illustrating how nations craft persuasive climate narratives to negotiate responsibility, leadership, and solidarity on the global stage.