It is our responsibility to analyze what is the most important thing we can do to make cities smarter when it comes to energy use.

Despite the fact that the world's cities occupy only 4 percent of the Earth's land surface, they are home to more than half of the world's population. By 2030, that percentage is expected to rise to 60 percent. In fact, the United Nations projects that cities will absorb most of the population increase in expected growth through 2050, more than two billion people.

This urbanization can become an advantage for the environment, since if growth happens in cities, they will become dense areas of population where their living spaces will use less energy and require fewer resources. But, it is true, there are concerns about increasing traffic congestion, smog and plague. A clear example is Beijing's greenhouse gas emissions per capita. These are higher than the Chinese national average, and many American cities are surrounded by suburbs with large carbon footprints. So that this does not happen throughout the world, it is important to pay attention to how we build cities, if we want metropolitan areas that make the planet a better place.

What is your opinion? What is the most important thing we can do to make cities more livable and sustainable in the use of energy? Here are some ideas and you can comment below with yours:

1. Urban transport systems need to become more sustainable

Having sustainable urban transport, giving priority to bicycles over cars, as was done, for example, in Copenhagen, introducing buses of rapid transit (BRT), or cable cars as part of urbanization, are strategies to reduce pollution.

2. Nature-based solutions work for cities, too

Nature-based solutions to avoid urban climate change and reduce disaster risk are clearly the most appropriate. An example is seen on the rooftops and green streets of New York City, thanks to which they can better manage stormwater and improve the urban climate. In China, the concept of "sponge cities" has been introduced, these cities have open spaces that absorb flood water and prevent disasters in an ecological way. There are more and more tools to support cities during the implementation phase.

3. Community networks can support urban disaster resilience

Floods, storms, or other natural disasters are usually worse in densely populated urban areas. The role of sustainable building codes, and planning to use the land correctly and reduce disaster risk, has long been recognized.

4. Smart solutions can improve urban livelihoods

For people who live in an informal settlement and do not have a proper address and bank account, it is often difficult to sign up for basic needs such as water and energy services. Digital technologies have arrived to solve these problems, like mobile money. These services facilitate transfers between urban and rural areas.

5. Cities, countries and international bodies need to collaborate

Sustainable and inclusive urban development must be a priority, not only in cities, but beyond urban limits. Countries are joining this movement internationally. In the case of the United Nations Conference on Housing and Sustainable Urban Development (Habitat III), they focused on sustainable urban development and adopted the “New Urban Agenda”. While good ideas are being implemented in different cities around the world, it is this type of collaboration that can make a difference globally.