Nick Mabey, founder and CEO of the global environmental think tank Leading E3G since 2006, has been a prominent figure in advancing climate policy and addressing the security implications of the climate crisis. Leading E3G, short for Third Generation Environmentalism, focuses on guiding international efforts towards a sustainable and low-carbon future.

Mabey has long emphasized the connection between climate change and national as well as global security risks, a perspective he promoted as early as the 1990s. His work has sought to position climate change not only as an environmental issue but also as a critical factor in geopolitical stability.

In 2019, Mabey partnered with the Mayor of London to launch the annual London Climate Action Week (LCAW), an event designed to bring together stakeholders from government, business, and civil society to accelerate climate solutions. Since its inception, LCAW has expanded significantly, becoming one of the world’s largest independent climate-oriented gatherings. The most recent event, held in June 2026, featured approximately 1,300 individual activities and attracted 75,000 participants. This edition coincided with London experiencing its first severe heatwave of the summer, underscoring the urgency of climate action. United Nations Secretary-General Antonio Guterres notably highlighted the situation, stating, “London’s not calling; it’s cooking,” to emphasize the extreme conditions.

Beyond organizing large-scale events, Mabey has contributed to the intellectual foundation of international climate economics and policy. He authored and co-authored a number of influential publications, including the 1996 book *Argument in the Greenhouse: The International Economics of Controlling Global Warming*, which addressed the economic challenges and opportunities of climate mitigation efforts at the global level.

In recognition of his leadership and sustained commitment to climate issues, Mabey was appointed an Officer of the Order of the British Empire (OBE) in 2022. His work continues to influence policymakers and advocates seeking to link environmental sustainability with broader security and economic strategies.