According to the Atlanta Business Chronicle, new population projections call for the Atlanta region to have 8 million residents by the year 2040. Current population is 5.5 million.“The 20-county metro Atlanta region is expected to reach a population of 8 million by 2040, according to a long-range forecast the Atlanta Regional Commission (ARC).”What does that 20-county region look like on a map? Below, I’ve blocked out the land area of those counties. This is where 5.5 million residents are now spread out.That’s a big chunk of north Georgia. You can see that the far western edge stretches to the Alabama line. Is that the size of land that has to be taken up my that number of people? Take a look at this image of Greater London’s footprint. This is where 8.4 million people live – a population count that’s a little more than the projection for the Atlanta Region’s in 2040.Those two maps are at the same scale. Here’s a direct comparison of the two at the same scale, in one image.Greater London obviously accommodates a large population in an area much smaller than Atlanta region, where the sprawl of the past several decades has pushed the boundaries of urban growth out in all directions with housing that takes a comparatively low-density form.This comparison between the 20-county Atlanta region and Greater London brings to mind two other popular images of Atlanta from the last few years. One shows the interchange of interstates 75 & 285 next to Florence, Italy, showing that they take up roughly the same space. Another image puts an older and smaller version of metro Atlanta’s footprint (from 1990) next to Barcelona, Spain and demonstrates how the same number of people can occupy vastly different stretches of land – which is pretty much what I’ve done above with London.I’ve seen a lot of comments online that mock these comparisons of Atlanta to european cities as being ridiculous. And it’s true that the geography, culture and history of Atlanta is very far removed from that of an old european city. But that doens’t need to translate to density as well. The history of Atlanta and its regional cities contains plenty of pre-car walkable density – we don’t need to think of strip malls, arterial roads and cul-de-sacs as the defining landscape for the region. Sprawl doesn’t have to be an innate, never ending part of our cultural identity.But more to the point, we can’t afford to think of density as un-Atlantan. I’ve heard many locals brag about their ability to withstand long drives to work or else boasting that they live in a suburb where everything they need is a 15 minute drive away. But what about the people who can’t afford a car, or who can’t afford to maintain one in good working condition, or who are unable to drive due to age or disability? Creating an environment where the mobility of those people is hindered, and where their attempts to walk to destinations are deadly – that’s nothing to be proud of.There’s been a good trend in new development taking place in walkable areas, but that’s been happening largely by way of market demands. Leaders need to ensure that all new transportation and development projects happen with an eye on sustainable, equitable mobility. The migration trend in Georgia and elsewhere toward urban regions will continue to put more and more people inside metro Atlanta’s largely car-focused built environment. This creates a mobility challenge we need to face head on by planning for new development that encourages public transit, bicycling and walking.The distance that our sprawling format has put between people and their jobs has dictated long commutes and created great distances between many homes and common destinations like grocery stores and doctors, often affecting the most vulnerable demographic segments the hardest (food deserts in Atlanta have gotten a lot of media coverage, but we also have doctor deserts – a challenge for aging Boomers). The overall health of the Atlanta region will depend on our ability to undo the damage of our car-centric built environments in the face of a growing population.