New research suggests that a reduction in carbon dioxide levels compared to neighbouring planets may indicate the presence of liquid water on a planet. The study, conducted by an international team of researchers, introduces a new ‘habitability signature’ as a practical method for detecting habitability. By comparing carbon dioxide levels in different planet atmospheres, this signature can identify planets with oceans, making them more likely to support life. The findings also provide insights into Earth’s environmental tipping points and the impact of carbon levels on habitability.