The phrase "urgent action on climate change" refers to immediate and decisive measures that need to be taken in order to address and mitigate the effects of global warming. It emphasizes the importance of taking swift, bold actions to reduce greenhouse gas emissions, protect ecosystems, and adapt to the changing climate conditions. The phrase is often used by environmentalists, scientists, policymakers, and activists who are calling for immediate action on climate change in order to prevent further damage to our planet.