This Costa Rican diplomat was appointed as the executive secretary of the UN's Framework Convention on Climate Change in 2010. Christiana first became interested in environmental issues after she realized that one of the species she loved growing up ~ golden toads ~ had become extinct by the time her daughters were born. Today, she's known as the architect or "force of nature" behind the historic climate deal signed by 195 countries in Paris in December of 2015.
Christiana was at the forefront of a 5-year process of brokering an international agreement to put the brakes on climate change by cutting back on fossil fuels + carbon emissions. It's the first time in history that 195 countries have agreed on anything ~ a sign that shows the world is ready to cooperate to save the planet we share.