I’ve been learning over the last few months how to make better use of the cornucopia of remote sensing data, satellites flying overhead snapping our picture, Instagram writ large. It offers a helpful reframing of my thinking about how water is spread across the landscape of New Mexico’s Middle Rio Grande Valley.

Sometimes we do it with intentionality and purpose, turning a farm field into a shopping center, running municipal lines to a new neighborhood, or abandoning an old one. (Yes, the latter has happened.) Sometimes the landscape grabs water on its own, trees dipping their roots into the shallow aquifer on the valley floor. Sometimes we do it because we value the green. Sometimes the change in green is just a side effect, water stuff just happens. Sometimes the satellite data helps answer questions. Mostly right now, for me, it suggests new questions to which I don’t know the answers.

Consider the map above. I’ve been staring at it for the last week in QGIS, the mapping software on my laptop. I built a Google Earth Engine app so you can stare at it too.

NASA’s Landsat satellites have been flying around snapping our pictures since the early ’70s, and with enough resolution beginning in the mid-’80s to begin seriously looking at the questions I’m interested in. The image above draws on algorithmic magic that creates an enhanced vegetation index showing which of the little pixels are vegetate – the thing we do with our consumptive use of water, making our desert landscape green. For the map above, I’ve colored each pixel to show the vegetation trend over time – blue ones have gotten more vegetated (by implication using more water), red ones have gotten less vegetated.

The map is full of “duh” moments – neighborhoods built since the 1980s are blue, as we turn desert into homes with trees and gardens, cars out front and kids’ basketball hoops in the cul-de-sacs. The former Kirtland Air Force neighborhoods along the northern edge of the base light up red. No more cul-de-sacs and basketball hoops, no more trees. The old farms of the South Valley that are no longer irrigated show up as big irregular red patches – Valle de Oro the most prominent, but the old Tobacco Farms property that’s now a Walmart, and the east side south valley farms that are now light industrial – red as well.

The riverside woods are largely greener, a riparian bosque flourishing after the combination of levees and an upstream flood control dam enabled our beloved forest to become what it is today. Except where it isn’t – the bits of red sprinkled through the bosque raise fresh questions.

The mix of blue and red on the valley floor tells a rich story – the expansion of the leafy village life of Corrales and Los Ranchos de Albuquerque as residents optimize around its mix of ditch water and unmetered domestic wells (and city water in Los Ranchos) while parcels farmed and irrigated decline. We’ve been looking at these patterns in bulk census data for years. The satellites let us see them, pixel by pixel, on the landscape.

Albuquerque’s near Northeast Heights, where I live, is fascinating. All that red! I could tell a simple just-so-story about municipal water conservation efforts that took hold in the mid-1990s, xeric gardens like mine. But it might be something as simple as a pattern of senescence of neighborhood trees build during the post-war boom of the 1950s. Maybe both? Tearing out lawns – the lawns from which they got water – dooming our aging trees?

There’s a big red pixel across the street from my house where our neighbor’s magnificent old cottonwood is no more.

There’s some sciency work going on behind all this, as my UNM colleagues and I turn toward bulk numbers and trends, trying to step away from the flattened landscape suggested by water agency numbers to the richer picture the remote sensing data offers of where the water is actually going in this coupled human-natural system, what we do with it, what we actually have reason to value.

But I also love the little stories. Every pixel tells a story.

A note on methods

The conceptual work – choice of methods, experimental design, iteration over various options of time periods, geographies, and remote sensing tools – is mine, with help from some of our smart students who have been teaching me about this remote sensing stuff for years. I use Anthropic’s Claude Code and OpenAI’s Codex for the software engineering. They are way better at writing code than I am. Most of the resulting code runs on Google Earth Engine, which supports my academic work with a generous free account.

In posting this publicly, a) I’m reasonably confident of what I’ve got, and b) I bear responsibility for the results.

A friend who has been part of the Ribbons of Green brain trust for the last six years reminded me over a taco truck library bench lunch today about the expectations I confront as the book emerges in the next six weeks into public view.

It’s not a water book. It’s a city book.

I mention the taco truck library bench lunch deliberately, because that is a city sort of a story – riding our bikes through the International District to check out the new park going in next to the library, then south to the taco truck in the lot next to the union hall, then zigging and zagging past a closed park to find a shady bench in front of the library on which to sit.

I’ve had the crud for nearly a month, and barely been on the bike at all, which is a striking break with my life’s rhythm. The problem with the break is not mainly the exercise, though not exercising when your body’s used to exercising is a problem. It’s the pattern of moving through my city on two wheels. It’s my practice, a city thing.

In the preface to Ribbons of Green, Bob Berrens and I frame the reasons we wrote this book the way we did:

Cities are one of humanity’s great inventions. People come together to share the social and economic benefits that flow from acting collectively at ever-larger scales. They are a tool for what the Bengali-born, Nobel Prize–winning economist and ethical philosopher Amartya Sen calls “capabilities”—the conditions that enable people to achieve what they have reason to value. Things like roads, food supply systems, and schools provide those collective capabilities, and all of them are enabled when people gather and share the cost of delivering them and the responsibility of guiding them toward the community’s desired future.

Our city shares an economic fabric that enables taco trucks (our red barbacoa truck, Zuni and San Pedro, was hoppin’ on a late Sunday morning) and a fabric of public goods that includes a really great library system (this was a two-library bike ride) and more deeply the vibrant cluster of humanity that is the International District on a cool spring Sunday.

There’s a weird naming convention in journalism, the “city desk,” the group of reporters who cover, well, the city. That’s where my roots are as a writer, a youngster at the late lamented Los Angeles Herald-Examiner, the last of L.A.’s gritty tabloids, a summer of unhappy chaos trying to make sense of a city in the midst of a crack epidemic and the Night Stalker and a food poisoning epidemic involving Jalisco cheese. I was there, working a late shift on the Herald-Examiner’s city desk, when we bestowed the name “the Night Stalker” on the serial killer terrorizing LA that summer. I was reading John Gregory Dunne and Joan Didion and imagining becoming the gritty chronicler of city life and failing terribly, lordy was I miserable, because I didn’t know the right questions. But it got me started on this other set of questions – the Lewis Mumford and Jane Jacobs and Edward Glaeser questions, the wonky frame around city life, to which I have happily returned.

To my water audience, I promise you’ll find lots of water stuff in Ribbons of Green. But its importance to our narrative is collective action around water as a means to the end of making a city, and to the big messy shared project of what we would like our city to become.

The park we had to bypass in search of a place to sit and eat tacos was all locked up, a response to encampments. I was pissed. My friend, Socratically wise in the ways of cities and knowing what was coming as I checked each of the park’s gates before stopping my bike and uttering an annoyed “What the fuck?”, just laughed. At both of today’s libraries, we saw city security people, even though both were closed. Cities are complicated, no one thing, ever in tension between competing and conflicting goals and values.

That’s what makes writing about them so interesting.