Five climate trailblazers: UNEP’S 2025 Champions of the Earth

As the world moves to slow climate change and create a more sustainable future, the UN Environment Programme (UNEP) named five new climate visionaries on Wednesday as its 2025 Champions of the Earth — the UN’s highest environmental honour.

These five extraordinary leaders, who work on issues ranging from climate justice to sustainable cooling and forest protection, show that bold action can drive real change for people and planet.

“As the global impacts of the climate crisis intensify, innovation and leadership across every sector of society have never been more essential,” said Inger Andersen, Executive Director of UNEP. 

“Young students demanding climate justice, subnational governments and architects leading on sustainable cooling and smart building design, research institutes slowing deforestation – and passionate individuals driving methane emissions reductions – this year’s Champions of the Earth show the kind of leadership that will inspire the world to face down the challenge of climate change.”

This year, the laureates are tackling some of the most urgent challenges of our time: climate justice, methane emissions, sustainable cooling, resilient buildings, and forest conversation, according to the UN’s environment agency.

UNEP’s 2025 Champions of the Earth are: 

Pacific Islands Students Fighting Climate Change – Policy Leadership

When Cynthia Houniuhi addressed the International Court of Justice in The Hague a year ago, she spoke plainly: climate change is devastating Pacific Island nations like her home, the Solomon Islands.  

Through her youth-led NGO, which secured a landmark International Court of Justice (ICJ) opinion affirming states’ legal duties to prevent climate harm and uphold human rights, she is helping to reshape global climate law and empower vulnerable nations. 

Indian environmentalist Ms. Sahu is redefining how communities adapt to extreme heat – restoring nature to cool cities, redesigning schools for safety, and promoting climate-smart infrastructure.  

Her sustainable cooling and restoration initiatives have created 2.5 million green jobs, expanded forest cover, and improved resilience for 12 million people. 

Mariam Issoufou, Principal and Founder, Mariam Issoufou Architects, Niger/France – Entrepreneurial Vision

By grounding her architecture in local materials and cultural heritage, Ms. Issoufou is redefining sustainable, climate-resilient buildings across the Sahel and inspiring a new generation of designers shaping Africa’s built environment.  

Through projects like the Hikma Community Complex in Niger, she pioneers passive cooling techniques that keep buildings up to 10°C cooler without air conditioning. 

Imazon, Brazil – Science and Innovation

Imazon has developed AI deforestation prediction models that inform policies and help law enforcement protect the Amazon rainforest, while promoting sustainable economic growth.        

By combining science and AI-driven geospatial tools to curb deforestation, Imazon’s non-profit research institute has strengthened forest governance, supported thousands of legal cases, and revealed the scale of illegal deforestation, driving systemic change in the Amazon basin. 

Manfredi Caltagirone (posthumous) – Lifetime Achievement

Mr. Caltagirone has dedicated his career to one of the most urgent challenges of our time. Guided by his vision for open, reliable, and actionable data, he has driven efforts to turn knowledge into climate action.  

As the former head of UNEP’s International Methane Emissions Observatory, he advanced transparency and science-based policy on methane emissions, helping shape the EU’s first regulation on methane emissions and shaping global energy policy.