In this article, Arup's Chris Edgington examines the evolving landscape of tall buildings in London, focusing on their carbon impact, longevity, and adaptability. He explores the challenges faced by ageing skyscrapers like the Gherkin and Tower 42 in maintaining relevance and meeting modern sustainability standards. The piece also discusses the importance of balancing embodied and operational carbon in building design and construction, highlighting recent initiatives in carbon accounting and whole-life carbon assessments. Using case studies of new developments in London's financial district, he illustrates various approaches to sustainable tall building design, including retrofitting existing structures and constructing new, carbon-efficient towers. He concludes by emphasising the need for tall buildings to be built with longevity in mind, acknowledging their higher carbon intensity whilst recognising their role in meeting urban density requirements.