Denver Mayor Michael Hancock has joined a high-level group of world leaders intent on putting a spotlight on migration caused by climate change.

The Climate Migration Council announced on Monday that Hancock and Makah Tribal Chairman Timothy Greene have signed on to the task force, which includes chef and World Central Kitchen founder José Andrés, former Homeland Security Secretaries Michael Chertoff and Janet Napolitano, and former CIA Director and Defense Secretary Leon Panetta.

The announcement comes days before the Cities Summit of the Americas is set to convene in Denver, bringing together municipal and other local leaders from throughout the hemisphere.

Formed last fall by Emerson Collective – a for-profit, philanthropic organization founded by Laurene Powell Jobs – the group aims to bring a sense of urgency to addressing the millions of people around the world who could be forced to move by climate-related disasters.

“The Climate Migration Council is an extraordinary group of leaders, and I’m proud to join them in this work to prioritize the communities most affected by the climate crisis,” Hancock said in a statement.

“All action starts locally, and when progress stalls at the national level, cities will step in to stand in the gap. We want to ensure our community is resilient and welcoming for generations to come, which is why climate action and sustainability are core values in the City and County of Denver.”

Hancock, who faces term limits in July, has been sounding the alarm on climate change for years. In his final State of the City address last summer, he argued for treating the threat seriously.

“Humanity has reached a crisis point in the fight against climate change, and the people who will suffer the most are the families and neighborhoods that are already the most vulnerable,” Hancock said. “Every day, every hour, every minute we delay means we are sacrificing our children’s future. That is an unacceptable injustice – we can and must do better.”

Greene, whose Makah Tribe is based in the Pacific Northwest, said climate change poses “unique risks” to indigenous communities and tribes.

“We know the climate crisis will demand creative means of adaptation,” he said in a statement. “By working locally and helping bring the perspectives of my people to the Council, I hope to add a unique perspective and to highlight the impact of climate change on indigenous communities.”

Editor’s note: This story h as been updated to reflect that the Climate Migration Council was formed last year by Emerson Collective, a for-profit, philanthropic organization founded and run by Laurene Powell Jobs, who is a member of the group.