Why Cities?

Ending Climate Change Begins in the City

Start scrolling your browser to learn why cities are the key to addressing the global climate change problem.

Why Cities?



Cities have the power to change the world.

For centuries, cities have been centers of commerce, culture and innovation, and the birthplace for some of humankind’s greatest ideas. At this critical crossroads in time, we need the ideas that cities can create more than ever.

But cities are as vulnerable as they are powerful.

70% of cities are already dealing with the effects of climate change, and nearly all are at risk. Over 90% of all urban areas are coastal, putting most cities on Earth at risk of flooding from rising sea levels and powerful storms.

Climate change causes financial damage too.

The financial effects of climate change can be just as devastating as the physical ones. Unexpected expenditures from storms, flooding, snow removal and drought can lead to major disruptions in business operations and city budgets.

Urban growth shows no sign of slowing.

Cities have become awesome in size, and also greenhouse gas emissions. Larger cities have a ravenous appetite for energy, consuming ⅔ of the world's energy and creating over 70% of global CO2 emissions.

But in the heart of the city lies an opportunity

Urban density presents a greener way to live

Urban density can actually create the possibility for a better quality of life and a lower carbon footprint through more efficient infrastructure and planning.

Why cities can be the solution to climate change.

City mayors are directly accountable to their constituents for their decisions, and are more nimble than state and national elected officials to take decisive action—often with immediate and impactful results. What our cities do individually and in unison to address climate change can set the agenda for communities and governments everywhere.

Local actions can have immediate impact and add up to create global effects

Collaboration between C40 Cities is
working—right now.

C40 is making a significant difference in improving the scale and speed of climate action, with 30% of all climate actions in C40 being delivered through city-to-city collaboration. When C40 Cities choose to take action on adaptation and mitigation strategies, and share knowledge with one and other, the collective impact is huge.

Today, nearly 10,000 climate change actions are in effect in C40 Cities, with over 78% of actions reported in 2015 planned for expansion.

Cities are our future.

We believe that a better global future lies in urban innovation and action. As the majority of future humans will live in cities, it just makes sense that our solution to climate change will reside there too.


There is no single solution for solving global climate change, but cities have the ability, capacity and will to lead.


Find out more about how cities are making changes.

Visit C40.ORG


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© 2012 C40 Cities, all rights reserved. Some illustrated elements sourced from Issara Willenskomer.