This is a tale of four cities, Calgary, Edmonton, Minneapolis, and Vancouver, each trying to answer the same question in a different way. How do you make room for more people in existing neighborhoods without pushing growth ever farther outward, and how do you do it in a way that lowers infrastructure costs, lowers transport emissions, lowers building energy use, and still survives contact with local politics? These four cities are useful comparators because they sit at different points on the same spectrum. Calgary made a bold citywide move and then reversed it. Edmonton rewrote the rules more quietly and kept them. Minneapolis made a narrower reform and embedded it in a broader planning framework. Vancouver turned infill into part of a full urban decarbonization package. Calgary has decided to do something that cities under housing pressure and climate pressure should avoid. It has taken a reform that was beginning to work, treated the backlash as more politically important than the evidence, and moved backward. The city’s 2024 Rezoning for Housing changed a broad swath of residential land so that lots that had largely been limited to detached houses could also accommodate forms like duplexes, rowhouses, townhouses, and secondary suites. Regressive councillors ran on repealing the infill rezoning, appealing to triggered NIMBYs and won, a very Alberta outcome. In April 2026, council approved repeal, with the main rollback taking effect on August 4, 2026, and most affected parcels returning to their prior low-density zoning. Applications filed before that date are grandfathered. It is an Alberta story in the familiar sense. A place starts to modernize, then retreats when the politics of change become louder than the economics and climate logic of change. The evidence on what works best is fairly clear. Density by itself helps, but the strongest emissions reductions do not come from density in isolation. They come from adding homes in location-efficient, transit-supportive, walkable neighborhoods, where people can shorten trips, substitute some car trips with transit or active transportation, and live in smaller or shared-wall homes with lower heating and cooling demand. The National Academies review Driving and the Built Environment concluded that compact, mixed-use development can reduce vehicle miles traveled, energy use, and CO2 emissions, but the size of the benefit depends heavily on where the development occurs and what other urban characteristics come with it. That matters because a fourplex in a car-dependent setting is still an improvement over a detached house on the suburban fringe, but it does not deliver the same result as a fourplex close to transit, services, jobs, and safe walking and cycling networks. The building-side math points in the same direction. Statistics Canada’s household energy data show that in 2021 the average single-detached household used 108.7 GJ of energy, while row or terrace housing used 80.8 GJ, duplexes used 77.7 GJ, and apartments in buildings with fewer than five storeys used 44.3 GJ. That means families in row housing used about 26% less energy than detached housing, duplexes about 29% less, and low-rise apartments about 59% less. Those are not small differences. They are the kind of structural efficiency gains that compound over decades across thousands of units. When a city legalizes missing-middle housing in established areas, it is not simply changing the look of a block. It is shifting average unit size, average exposed building envelope, average heating demand, and often average travel distance at the same time. Calgary’s reform aligned with part of that logic but not with all of it. The citywide rezoning was broad. It changed what could be built on large numbers of lots in existing neighborhoods, and Calgary’s own 2025 housing strategy progress report said it had enabled 46% of all new low-density housing development permits in the established area, resulting in 814 new units and 765 new secondary suites. Those are meaningful numbers for a policy barely out of the gate. But the reform was framed and attacked as a single dramatic act, blanket rezoning, which made it easy to mobilize against. It was not anchored tightly enough to transit-oriented development, not wrapped tightly enough inside a larger planning modernization story, and not protected from a change in council. Calgary was not wrong to liberalize infill. It was fragile in how it did it. Edmonton offers the first contrast. Its Zoning Bylaw Renewal and associated citywide rezoning were approved in October 2023 and took effect on January 1, 2024. The city’s RS Small Scale Residential Zone allows a range of small-scale residential development up to 3 stories, including detached, attached, and multi-unit housing. On an interior lot, the maximum is eight dwellings, with a minimum site area per dwelling of 75 square metres. That is a more permissive lot-level framework than many casual observers realize. Edmonton also modeled the climate implications of more compact growth in its City Plan work. In the preferred compact scenario, the result was a 6% per person reduction in greenhouse gas emissions compared with today. In the broader scenario work, the most compact option cut 2065 emissions to 3.25 million tons from 14.47 million tons in the business-as-planned case, with 11% of the reduction attributable to land use and transportation policy. Edmonton did not publish a single clean number for the zoning bylaw alone, but it did something more important. It built a permissive framework and linked compact form to lower VKT and lower emissions. What Edmonton got right was not only the substance, but the packaging. It did not present infill reform as a one-shot ideological confrontation with the detached-house city. It treated it as part of a larger zoning rewrite to support growth, equity, resilience, and adaptability. That reduced the symbolic temperature. NIMBY concerns did not disappear. Edmonton’s public engagement documents show recurring worries about traffic, parking, sun access, and neighborhood change, the same concerns heard in every North American city. But the city turned the argument into an administrative modernization exercise rather than a singular political showdown. That matters because zoning reform survives better when it looks boring, durable, and embedded in the normal machinery of planning. Minneapolis took a different path. Its headline reform was narrower on the typical low-density lot. The 2019 ordinance tied to Minneapolis 2040 permitted up to three units on a zoning lot in several formerly single-family-oriented districts. That is less sweeping than Edmonton’s eight-unit RS framework and less permissive on raw unit count than Vancouver’s multiplex rules. But Minneapolis embedded the reform inside a larger comprehensive plan and transportation strategy. The city’s Transportation Action Plan says on-road transportation accounts for about 24% of local greenhouse gas emissions and that even with mass adoption of electric cars, Minneapolis still needs to reduce automobile passenger miles by 38% to meet its climate goal. That is exactly the land use and transport linkage the research points toward. Minneapolis did not treat triplex legalization as the whole answer. It treated it as one component of a city in which people need to drive less. That narrower but better-integrated approach helps explain why Minneapolis held its reform. Opposition existed there as well. Legal fights dragged on for years. But the reform was not just a standalone zoning tweak. It was part of a citywide planning framework that connected housing, transport, climate, and equity. That made it harder to unwind. It also gave the city a clearer defense. The case for change was not simply that more units might ease housing pressure. The case was that urban form and transport are linked systems, and a city that wants lower emissions cannot keep reserving large parts of itself for detached housing alone. Minneapolis is the example of a city that went less far on the lot, but farther on policy integration. Vancouver is the city that comes closest to doing what the evidence says works best. Its R1-1 Residential Inclusive district allows multiplex housing of up to six dwelling units, or up to eight secured rental units, on a single lot across a large share of the city. But the zoning is only part of the story. Vancouver also requires zero-emissions equipment for heating in new low-rise residential buildings, a requirement in place since January 1, 2022, and the city states that by 2030 all new homes will be zero emissions in operation. On the transport side, Vancouver’s climate materials say nearly 40% of the city’s carbon pollution comes from gasoline and diesel in vehicles, while over half comes from natural gas used to heat space and water in buildings. That means the city’s infill approach is not just about allowing more homes. It is about putting more homes into a city where the building systems are being electrified and where transport alternatives already exist and are being strengthened. The result is that Vancouver’s likely emissions payoff per added unit is stronger than Calgary’s and Minneapolis’s, and in some respects stronger than Edmonton’s, even if Edmonton remains highly permissive on unit counts. Vancouver is attacking both of the biggest urban emissions buckets at the same time. Add a multiplex instead of a detached house, and you gain on shared-wall efficiency and average unit size. Require zero-emissions heating and hot water, and you eliminate operational combustion in the new building. Put that housing in a city with a high transit, walking, and cycling share, and the transport side improves as well. This is what infill as climate policy looks like. It is not just zoning. It is zoning, building code, and transport policy working in the same direction. Seen side by side, the four cities reveal a hierarchy of what works. Calgary changed entitlements and then retreated. Edmonton changed entitlements broadly and kept them. Minneapolis made a smaller entitlement change but embedded it in a stronger transport and climate frame. Vancouver combined entitlements, zero-emissions buildings, and transit-oriented urbanism. If the test is simple housing permissiveness, Edmonton and Vancouver come out well. If the test is climate alignment, Vancouver and Minneapolis are stronger. If the test is political durability, Edmonton and Minneapolis look better than Calgary, with Vancouver benefiting from provincial and local policy alignment that has pushed cities in British Columbia toward more permissive infill. The larger lesson is that good reform is not only about how many units a lot can hold. It is about whether the surrounding policy stack makes those units low-carbon, low-car, and hard to politically reverse. There are lessons here for other cities. First, do not sell infill only as a housing supply measure. It is also infrastructure efficiency policy. Every household accommodated in an existing serviced neighborhood avoids some combination of new road expansion, longer utility runs, longer car trips, and larger housing forms. Second, do not isolate zoning reform from transport and building policy. The strongest emissions outcomes come from the package. Third, do not make reform easier to caricature than it needs to be. A comprehensive zoning rewrite may be less exciting than a dramatic blanket rezoning vote, but it may survive longer. Fourth, cities should quantify the benefits better. Calgary had output numbers but not a clean avoided-emissions forecast for the rezoning itself. Minneapolis had transport logic but not a zoning-only emissions number. Edmonton got closest on scenario modeling. Cities that want these reforms to hold should measure avoided VKT, avoided building energy demand, and avoided tons per thousand units added. There are also lessons for provinces, states, and national governments. Higher levels of government should not just urge cities to permit infill. They should create durable scaffolding around it. That means tying housing and infrastructure funding to location-efficient growth, aligning building codes with electrification, and protecting local reforms from being casually reversed after one election. Calgary’s rollback is a reminder that municipal reform can remain provisional if it sits alone. Vancouver’s experience suggests the opposite. When local zoning reform is reinforced by building rules and broader provincial housing direction, it becomes part of a larger system rather than a local experiment waiting to be repealed. The climate case for infill is not complicated. Smaller homes tend to use less energy. Homes in central neighborhoods tend to generate less driving. Electrified buildings cut combustion emissions. The hard part is not the math. It is the governance. The tale of four cities ends, for now, with four different answers to the same urban question. Calgary shows how a real reform can be politically exposed and reversed before its benefits become embedded. Edmonton shows that broad change can stick when it is normalized through institutional redesign. Minneapolis shows that a narrower reform can still matter when it is tied to a larger plan for lower car dependence and lower emissions. Vancouver shows the most complete model, where infill, electrification, and transit-supportive urbanism reinforce one another. If there is one clean lesson from the four, it is that cities do not succeed by legalizing density in the abstract. They succeed by making infill part of a wider low-carbon urban system and by designing the politics, not just the zoning, so that the future can survive its first backlash.
