Introduction: The evolution of news coverage of climate change during the last twenty years coincides with the emergence, expansion, and consolidation of digital media in Spain. The objective of this study is to explore online communication on climate change in Spain, identifying the main sources of information and the characteristics of the communication they practice. Methodology: From a quantitative approach, all the records obtained during the first online probe carried out by the Observatory for Climate Change Communication are analyzed (data from Kantar Media). Results: There is a trend similar to conventional media in terms of seasonality, schedules, and coverage. The main general and specialized sources of information are identified, establishing a ranking with the thirty most relevant, and the "sentiment" associated with the speeches is analyzed. A content analysis protocol is applied to identify the sources of information about CC on the Internet and the thematic content. Discussion: The general press is the undisputed leader in the online environment due to the low volume of publications on climate change on radio and television on the Internet. Sectorial associations, companies, and municipal or regional institutions are the main sources of specialized information together with the press. The Europa Press news agency ranks first in terms of the volume of information published in the ranking of the thirty main sources of online information. Conclusions: We find great transversality of climate change as an informative reference, which is communicated by specialized sectors such as the economic and financial sector and by various media concerned by the ecological transformation in the social context of the climate emergency of 2019.