Read on to explore the chat topic, questions, and highlights from the discussion.

More than half of the world’s population lives in urban areas and this number continues to grow, with 1.2 million people migrating to cities every week. Three-quarters of the world’s largest cities are located on coastlines, and critical infrastructure – including water and sanitation, transportation, energy and information technology – is vulnerable to climate impacts, such as rising sea levels, floods, heat waves and higher winds. Inadequate infrastructure, housing and basic public services may exacerbate the effects of climate change and threaten people’s health and livelihoods.

In cities around the world, innovative and creative solutions are being applied to reduce climate risks and build resilience to climate change. Through the sharing of knowledge and best practices, this Twitter chat highlighted how cities around the world, particularly in developing countries, are applying adaptation and mitigation actions to become more resilient to climate change and other threats. Participants offered information about cities and urban initiatives we can look to as examples and replicate, the biggest challenges to building resilience and how they have been addressed, and how cities will honor commitments made at COP 21.

Question 1: Why are cities hubs for tackling climate change challenges?

Question 2: What are local governments, organizations, and communities doing to help cities mitigate and adapt to climate change?

The above tweet links to the Cities100 report, developed in collaboration with Sustainia, C40 Cities and Realdania, which highlights successful climate solutions cities are implementing around the world.

The above tweet links to the ICMA CityLinks Primer on Subnational Approaches for Low Emission, Climate Resilient Development. The primer, developed in collaboration with the Institute for Sustainable Cities and funded by USAID, aims to encourage collaboration between international development stakeholders and city officials.

Question 3: Why apply a resilience lens to climate change mitigation/adaptation? Does resilience address other urban challenges?

The above tweet links to the USAID Climate Change Resilient Development (CCRD) Project Compendium. CCRD was a four-year project (2011-2015) under USAID's Global Climate Change Office.

Question 4: What are barriers to building resilience to climate change in cities?

The above tweet links to the C40 Cities "Unlocking Climate Action in Megacities" report published ahead of the Climate Action Summit in May 2016.

Question 5: What tools, technology & scientific data are helping city officials, planners, and practitioners with decision making and planning?

The above tweet links to the "Development of an Urban Resilience Analysis Framework with Application to Norfolk, VA" report developed by Sandia National Laboratories.

Question 6: How can cities make public infrastructure and services like water, sanitation and transportation climate-resilient?

The above tweet links to the "Making Water Systems Climate Resilient: Lessons from Typhoon Yolanda" fact sheet which outlines the storm's key impacts on water systems and provides recommendations on how they can be made more resilient to disasters and climate change.

The above tweet links to USAID's Sustainable Urban Services Policy which offers guidelines to help countries and communities improve the delivery of essential services in urban areas.

The above tweet links to the United Nations Development Programme Environmental Procurement guide.

Question 7: How are cities around the world collaborating to support climate resilience?

The above tweet links to the "Urban Climate Change Resilience in Action: Lessons from Projects in 10 ACCCRN Cities" report which presents insights from the Rockefeller Foundation's Asian Cities Climate Change Resilience Network program.

Question 8: What private sector, civil society, local government and donor partnerships are providing solutions to climate resilience?

The above tweet links to the "How to build science-action partnerships for local land-use planning and management: lessons from Durban, South Africa" report published by Jessica Cockburn, et al.

Question 9: What steps are cities taking to honor commitments made at COP21?

The above tweet links to the "Ten Key Principles of Low Carbon Urbanization: Supporting China’s New Type of Urbanization" report developed by ICMA in collaboration with 18 other non-profit organizations.