Some of you are probably shocked by this headline. But it is true. Here's the chart to prove it:
Toronto is number one. Los Angeles is number two. And New York sits just behind Winnipeg and Calgary. Huh?
The reason this is likely surprising to you is that when most people think of urban density they think of the urban core. And you are correct in thinking that the urban core of New York City is denser than the urban core of Winnipeg.
The difference here is that we are talking about "urban area" (or "population centre" in Canada). This is the continuously built up area around each major city. Think of it as the lit up area that you might see on a nighttime aerial photo.
Urban areas don't care about municipal or other jurisdictional boundaries. And they don't factor rural areas. Urban areas are a measure of continuous urbanization.
So even if you have the densest downtown on the planet, if you have a sprawling low-density urban area surrounding it, you can still end up with a relatively low overall population density. And this is precisely what is happening here with New York.
This is also why there's only so much that you can glean from a blended average like this. Because you can have very different urban forms and very different mobility splits (think New York City vs. Winnipeg), and still end up with somewhat comparable averages.
Chart: New Geography
Following my recent post about the largest cities in the world (from 100 to 2015 CE), a number of you rightly pointed out that the data looked questionable. Where, for example, is Shanghai in this latest list of largest cities? So I think it's important that I do a follow-up post.
There are a number of nuances to consider when trying to measure urban populations. Perhaps the two most obvious are the geographic extent of each city (i.e. what urban boundary do you use) and the number of people living in informal settlements.
The UN recently estimated that there are some 1 billion people living in slums or informal settlements. That represents nearly a quarter of the world's urban population, which is a staggering number and a pressing global need. We desperately need more housing.
When it comes to measuring the size of an urban agglomeration, most of the studies that I have seen tend not to focus on municipal boundaries ("city propers") or metropolitan areas. The former is often based on arbitrary political boundaries and the latter often contains undeveloped rural land.
So for the purposes of this post, I'm going to go with Demographia's definition of "built-up urban area." They define this as being a continuously built-up area with one labor market and with no rural land. In their view, the world is either urban/built-up or rural. The built-up part is the lighted area that you would see on a nighttime satellite photo.
Given this definition, there are a number of interesting fringe cases. For example, contiguous/adjacent urban areas with more than one labor market get split up into multiple ones. This is the case in the US with the northeastern "megalopolis" that runs from Boston to Washington.
Conversely, if adjacent urban areas share a labor market and are linked together by similar commuting flows, then they get grouped into one urban area. This might be the case even if the area(s) straddle a national border. In this particular case, the free movement of people and goods would be another prerequisite.
With these definitions out of the way, below is another stab at sharing an accurate list of the world's largest megacities or built-up urban areas. This is one is by Demographia and there are a number of key changes compared to the last one I shared. Shanghai now features in the top 10. But Lagos drops down to number 20, which remains a bit of a question mark for me.
For a copy of Demographia's full report, click here. It looks at all urban areas with a population greater than 500,000 people (total is 985). Of course, if any of you have any other data sources that you think I should take a look at, feel free to share them in the comment section below.