We’ve previously written about whether we should focus on addressing climate change at the city level, or the country level.
What we do know is that roughly 70% of global greenhouse gas emissions come from cities (some sources say it’s higher when accounting for all production and consumption emissions)
So, this is a guide about how cities might address climate change at the city level.
Summary – Reducing Emissions & Addressing Climate Change In Cities
There might be some specific solutions to consider, but also some general solutions and considerations. These are:
– The emissions from a city tend to be directly related to how clean the energy mix in the city.
So, there will be a need to switch from carbon intensive energy sources like coal and oil to less intensive energy sources like renewables and nuclear.
Natural gas is slightly less carbon intensive than coal and oil, but more intensive that renewables and nuclear
– Increase efficiency of electricity production
– Increase energy efficiency of buildings – of building energy systems and designs (especially with the consumption of electricity for heating, cooling, refrigeration and lighting).
Retrofitting, and new builds
We might consider the role of technologies like Artificial Intelligence technology and systems in more sustainably or efficiently using energy
– Have less total vehicles, and decrease total distance travelled within the city (as well as tourism and travel in and out of the city)
– Increase efficiency of per passenger emissions (can do so via public transport for example), as well as efficiency of transport overall
– Increase walking, biking and public transport where possible as opposed to single person and private vehicles
If cities would switch to a more efficient energy source or make their public buses electric … they could slash their emissions by at least 25 percent (scientificamerican.com)
– Focus on reducing emissions in other sectors as well, like food consumption, food waste and loss, waste management, government, road, pathways and infrastructure, health and education, and so on
[Energy generation and buildings, and transportation may be some of the biggest areas to focus on in developed cities. Food, waste, and water might be others]
– Build cities up instead of out (per capita footprint tends to be lower in denser cities that are built up instead of out, and that are more compact and efficient in their design)
– Decrease urban sprawl
– Consider the impact of population size on a city – this generally increases energy demand (for electricity, accomodation, transport, freshwater, and so on)
– Increase population density and number of people per square area – as opposed to thinly populated cities
– Make sure the design of the city and infrastructure is well planned out
– Have efficient living spaces
– Make sure living spaces are close to public transport and services
– Make sure power plants are located close to cities with shorter transmission lines
– Try to concentrate energy and electricity production where possible
– Live less affluent lifestyles
– Consider changing diets to reduce emissions at the agricultural, forestry and land use level [reducing food waste and loss is also another opportunity to do this]
– Decrease total consumption, consumption rate and overconsumption (some reports indicate this will have a bigger and more effective impact than changes to energy sources and transport where total consumption isn’t actually decreasing)
– Decrease total energy use
– Decrease intensity and rate of energy use
– Consider adding vegetation and greenery to cities and around cities (on rooftops, on facades, and on sequestration towers)
General Solutions & Considerations
– Have a custom strategy and plan for each individual city based on the emission profile of the individual city
– Consider both total emissions, and emissions per capita of a city.
There’s also another measurement not used as often – the carbon intensity of an activity.
– Consider the lifecycle of products and materials for a full carbon footprint – production, consumption, exported, imported, inside the city boundaries, and outside the city boundaries [some cities may import a huge amount of emissions from goods and services made or produced elsewhere]
– Consider that there’s various factors to take into account when measuring city emissions footprints, and there’s complexities, difficulties and limitations to doing so
– Get an accurate picture of the geographic boundaries of a city for an idea of where emissions are happening – so accurate assessments can be made.
Understand how far up the production and supply chain you are counting emissions – indirect supply, transport, delivery and manufacturing chain can all be included or excluded.
Understand where emissions take places, and who is responsible for them.
Variables like deforestation and mining can be difficult to factor into carbon footprints for cities because of how disconnected they can be from final consumption
– Consider the sectors that make up the biggest % share of emissions – focus on the sectors most responsible
– Understand that rural, urban and CBD/built up city areas all tend to have different emission rates.
– Focus on – the most developed and wealthy cities, and the small number of big cities in the world responsible for the highest share of total emissions.
The most economically developed, urbanized, and affluent/richest (in terms of lifestyle) cities in the world tend to have the highest total carbon footprints (read a list of the largest emitting cities in the world here).
There’s about 100 of these types of cities that make up around 20% of total global greenhouse gas emissions.
– As developing cities grow and use more energy, put more focus on them. About 90% of future city emissions will come from developing cities.
– Understand the difference between the profile of a developed and wealthy city, and a developing city.
Developed cities tend have more emissions come from building energy (heating, cooling, refrigeration, lighting etc.)., and developing cities tend to have more emissions come from industrial activity
– Understand the difference between the profile of a consumer city, a producer city, an exporter city, and an importer city.
Consumer cities tend to have higher footprints in reality, and the producer footprint should technically be counted for these cities when they import from a producer city.
Consumer cities (outsourcing production elsewhere but consuming inside the city boundaries) tend to be big developed cities, whilst developing cities tend to tilt towards being production cities.
Service-based economies that consume the things that other cities make can rank better for emissions in some calculation – so new carbon footprint calculations need to take into account inside and outside city emissions and reflect what consumer cities buy from producer cities
– Focus on consumer cities which tend to have higher emissions footprints
– Understand that mitigation (reducing emissions), sequestration (absorbing emissions), and adaptation (adapting to the effects of warming or cooling) are three pillar solutions
– Accept that some cities (due to layout, design and geography) are locked into some limitations
– Consider how addressing emissions can fit into an overall sustainability strategy for a city
– Consider that cities might have more direct influence over sector based emissions compared to indirect energy usage further up the supply chain
– Consider the impact that new technology like desalination plants and electric vehicles will have on energy use – generally more energy will be used
– Social norms and culture within cities can impact emissions – if more people buy into the concept of sustainable cities, emissions might be lower based on behavior and other factors
– Understand that factors like climate, geography, economic and sectoral profile, and other variables can impact individual cities
Examples Of Cities Who Have Already Decreased Their Carbon Footprint
In the guide further below, we list examples of cities that have already decreased their carbon footprint, and in some cases how they did it.
*Note – Every city is different and has it’s own unique carbon footprint profile – in terms of quantity of emissions, and where emissions come from (the activity that produces the emissions, the sector, whether they come from inside or outside the city via direct emissions or imported emissions from goods made elsewhere, and so on).
So, each city will need an individual plan to address emissions (mitigation, adaptation, sequestration, etc) and one that also fits into an overall sustainability plan (to address broad sustainability issues like water supply, air pollution, land degradation, overpopulation, and so on.)
Ideally, solutions and strategies to reduce emissions or address climate change would be suited to the profile of the city – developed vs developing, consumer city vs producer city, and identifying the sectors and activities in the city that emit the most GHGs, and where there is most potential for positive results.
Cities are well placed compared to countries as solutions and strategies may be able to be implemented more quickly and effectively than at the national or even State/province wide level (or even global level).
In the guide below, we’ve outlined that some of the biggest cities in the world have already put in place measures to decrease and peak their emissions.
We’ve also listed some of the ways they’ve done this.
It’s worth noting that reducing th carbon footprint of a city is one of the factors that contributes to how sustainable or green a city is.
Solutions & Strategies For Reducing Emissions & Addressing Climate Change In Cities
We’ve paraphrased and listed ideas and solutions from various sources below (and expanded them, or connected them to other ideas ourselves) about how some cities might decrease emissions and address climate change.
Check out the resources list for the full resource if you’re interested:
Place a focus on the top 100 to 500 cities for addressing total emissions
Place a focus on the top 100 to 500 cities for addressing per capita emissions
Radical decarbonization measures (limiting non-electric vehicles; requiring 100% renewable electricity) can induce substantial emissions reductions beyond city boundaries.
In wealthy, high-consumption, high-footprint localities such measures may require only a small investment relative to median income, yet accomplish large reductions in total footprint emissions
Local action at the city and state level can meaningfully affect national and global emissions
You have to know the scope included in the final footprint – what emissions are being counted, what source are they coming from, are they counted inside or outside the city, and how far back in the manufacture or supply process is being counted (just as examples)
When addressing climate change involves mitigation, adaptation and sustainability strategies … areas to focus on for solutions might be:
Adaptation and implementation – connecting cities, cool cities, urban flooding
Improving Air Quality – minimising air pollution and emissions
Energy and buildings – Clean Energy, Municipal Building Efficiency, New Building Efficiency, Private Building Efficiency
Transport – Land Use Planning, Mass Transit, Mobility Management, Walking & Cycling, Zero Emission Vehicles
Food, waste and water – Food Systems, Sustainable Waste Systems, Waste to Resources
Examples Of Cities That Have Already Reduced Greenhouse Gas Emissions
Something they mention about cities currently attempting to reduce emissions:
27 of the world’s greatest cities, representing 54 million urban citizens and $6 trillion in GDP have peaked their greenhouse gas emissions.
New analysis reveals that the cities have seen emissions fall over a 5 year period, and are now at least 10% lower than their peak.
The cities are: Barcelona, Basel, Berlin, Boston, Chicago, Copenhagen, Heidelberg, London, Los Angeles, Madrid, Melbourne, Milan, Montréal, New Orleans, New York City, Oslo, Paris, Philadelphia, Portland, Rome, San Francisco, Stockholm, Sydney, Toronto, Vancouver, Warsaw, Washington D.C.
Some of the ways they achieved this were:
Decarbonisation of the electricity grid
Optimizing energy use in buildings
Providing cleaner, affordable alternatives to private cars
Reducing waste and increasing recycling rates
Investment in sustainable infrastructure and policies
Collaborating with national and regional governments and businesses operating within cities, as well as citizens, to deliver the collective action needed to cut emissions
Tracking How Cities Are Addressing Climate Change & Sustainability
5. Moran, D., Kanemoto K; Jiborn, M., Wood, R., Többen, J., and Seto, K.C. (2018) Carbon footprints of 13,000 cities. Environmental Research Letters DOI: 10.1088/1748-9326/aac72a