A new leader is set to guide one of the world’s major environmental financing institutions as the Global Environment Facility (GEF) Council selects Diego Mesa Puyo as its next CEO and Chairperson. The announcement marks an important leadership change for the GEF as countries work to increase financing for climate action, biodiversity and other environmental priorities ahead of 2030.
The GEF Council announced Mesa Puyo’s selection on August 5, 2026. He is expected to take up the position at the beginning of October 2026 and will serve an initial four-year term. His term will align with the GEF-9 funding period and the final years of the international effort to achieve key environmental goals by 2030.
Diego Mesa Puyo Brings Climate Policy Experience
Mesa Puyo brings experience from both government and international economic policy. Before his selection for the GEF position, he served as Deputy Chief of the Climate Policy Division at the International Monetary Fund (IMF). The IMF has previously listed Mesa Puyo in that role during its climate policy discussions, including its COP28 program. He also served as Colombia’s Minister of Mines and Energy from 2018 to 2022. During his time in government, he worked on energy policy, market reforms and the country’s energy transition.
According to the GEF, the reforms carried out during his tenure helped mobilize more than $3 billion in private investment. They also supported the expansion of variable renewable energy in Colombia, which moved from near-zero deployment to becoming one of the fastest-growing clean-energy markets in the region. Mesa Puyo also contributed to policies and legislation connected to Colombia’s energy transition and climate objectives. His background gives him experience in developing public policy while also working to attract private investment, an area that will remain important for international environmental financing.
A Major Leadership Change for the GEF
Mesa Puyo will succeed Interim CEO and Chairperson Claude Gascon, who has led the GEF since December 2025. His expected arrival in October will therefore begin a new leadership period for the organization. The CEO and Chairperson role carries responsibility across the GEF family of funds. This includes the GEF Trust Fund, the Global Biodiversity Framework Fund, the Least Developed Countries Fund and the Special Climate Change Fund.
The GEF supports developing countries as they address major environmental challenges, including biodiversity loss, climate change, land degradation, international waters and pollution. Its financing is designed to help countries implement environmental priorities while attracting additional resources from other partners.
GEF Has Mobilized Billions in Environmental Finance
The leadership transition comes as the GEF continues its work through its ninth replenishment cycle. According to the organization, donors have pledged an initial $3.9 billion for the ninth replenishment of the GEF Trust Fund.
Over more than three decades, the GEF family has provided more than $27 billion in financing and helped mobilize another $155 billion for country-driven environmental projects and priorities. These resources have supported governments and partners working on environmental challenges across developing countries. The scale of this financing makes the leadership transition significant. The next few years will require continued coordination between governments, development institutions, private investors and other organizations to turn environmental commitments into projects on the ground.
Mesa Puyo Sets Out His Priorities
Following his selection, Mesa Puyo said he was honored to take on the role at an important moment for global environmental action. He highlighted the need to work with trusted partners, integrate solutions and attract investment that can produce measurable results for people and the planet.
His previous work in energy transition and climate policy could play an important role as the GEF seeks to connect environmental objectives with economic development and investment. The organization will also need to maintain cooperation among its member countries and funding partners while addressing several environmental challenges at the same time. Mesa Puyo’s experience across government and the IMF provides a background that combines national policymaking with international economic and climate discussions.
Looking Ahead to October
Mesa Puyo is expected to formally take up the GEF CEO and Chairperson position at the beginning of October 2026. His initial four-year term will coincide with the GEF-9 period and will cover a critical part of the run-up to 2030. As he prepares to take charge, the focus will be on how the GEF can use its funding and partnerships to support practical environmental action. His experience in energy policy, climate finance and investment mobilization will now be brought to a global institution working across multiple environmental priorities.
The appointment places Diego Mesa Puyo at the center of an important period for international environmental finance, with the GEF preparing to enter its next chapter under new permanent leadership.
