Longtime environmental activist and climate change expert Christiana Figueres will assume duties as the United Nations' new climate chief, UN Secretary General Ban Ki-moon announced Monday.

She was nominated by former Costa Rican president Oscar Arias, who said that her appointment would be “an honor for our country and an intelligent and visionary decision for the UN.”

The daughter of three-time president and Costa Rican legend Jose “Pepe” Figueres, 53-year-old Christiana Figueres made a name for herself in the environmental realm as lead negotiator for Costa Rica at international climate change forums.

She was the founder and Executive Director of the Center for Sustainable Development in the Americas (CSDA), a non-profit think thank for climate change policy and capacity building. 

Figueres also served as vice president for Latin America and Caribbean countries on the director's council of the U.N. climate change treaty from 2008 through 2009. In addition, she represented Central America on the executive board of the Clean Development Mechanism (CDM), a funding organization established pursuant to the climate change treaty.

She assumes the position at a pivotal time in climate change history, as an increasing number of countries are adopting the issue as a priority but have been unable to come to an agreement over a shared commitment to reduce carbon emissions.

“Ms. Figueres is an international leader on strategies to address global climate change and brings to this position a passion for the issue, deep knowledge of the stakeholders and valuable hands-on experience with the public sector, the nonprofit sector and the private sector,” said the UN president's spokesman, Martin Nesirky, in a press release.

She will replace current climate chief Yvo de Boer of the Netherlands, who steps down July 1, to pursue private endeavors.