Most Australians live in cities. Our four largest cities – Sydney, Melbourne, Brisbane and Perth – account for more than half the nation’s population. These coastal cities need to prepare themselves for the impacts of climate change, of which rising seas is just one. But coastal cities around the world aren’t the only ones that need to adapt to climate change.

In the middle of Mexico, high in the mountains, Mexico City has a population of over 21 million. Climate change is exacerbating some of the key challenges facing the city, as it is doing in cities throughout the world.

In a recent article, The New York Times stated, ‘Around the world, extreme weather and water scarcity are accelerating repression, regional conflicts and violence. A Columbia University report found that where rainfall declines, “the risk of a low-level conflict escalating to a full-scale civil war approximately doubles the following year.” The Pentagon’s term for climate change is “threat multiplier.”’

The article quotes Arnoldo Kramer, Mexico City’s chief resilience officer: ‘Climate change has become the biggest long-term threat to this city’s future. And that’s because it is linked to water, health, air pollution, traffic disruption from floods, housing vulnerability to landslides — which means we can’t begin to address any of the city’s real problems without facing the climate issue.’

Supplying this sprawling city with water is a challenge. Turning on the tap is a lottery for one in four residents. Some get water only once a week.

‘Climate change is expected to have two effects,’ Ramón Aguirre Díaz, Director of the Water System of Mexico City told The New York Times. ‘We expect heavier, more intense rains, which means more floods, but also more and longer droughts.’

Any cessation of rain over the city’s reservoirs would be disastrous. ‘There is no way we can provide enough trucks of water to deal with that scenario,’ said Ramón.

Climate change projections for the region make grim reading. According to a 2013 paper by Fabiola Sosa-Rodriguez from the Universidad Autonoma Metropolitana, mean temperature in Mexico is projected to rise by 2 to 4 °C from 2020 to 2080, and precipitation levels are projected to fall by up to 15 per cent in winter and up to 5 per cent in summer. The surface temperatures of the Caribbean Sea, Gulf of Mexico and the Mexican Pacific are expected to increase by 1 to 1.5 °C, ‘a situation that favours the occurrence of more frequent and intense hurricanes’.

What are the climate change projections for your region?
What adaptation measures are you planning?

To learn more about Mexico City’s problems, read the New York Times article Mexico City, Parched and Sinking, Faces a Water Crisis