Honolulu Mayor Kirk Caldwell is off to Denmark this week for a global gathering of big city mayors. Their goal is to tackle the major challenges of climate change.

The group C40 is a network of 94 so-called “mega-cities” from around the world. It's essentially a city-level equivalent to the G20.

The group represents more than 700 million people and one quarter of global economic output.

They’re also responsible for a lot of carbon emissions, almost 7 percent of annual global totals.

Every other year since 2005, the C40 has convened to promote and develop solutions to climate change, a problem the group says city governments are taking the lead on.

Honolulu is not a member of the C40, but was invited to attend this year’s conference in Copenhagen to showcase the work being done locally to prepare for a future of climate change.

In June, the city Office of Climate Change, Sustainability, and Resiliency released a long-term strategy detailing how the community will need to adapt for that uncertain future.