Driven by rapid economic expansion and global trade, the world’s urban population has more than quintupled since the mid-20th century, from 751 million people in 1950 to 4.2 billion today. Centuries-old cities have pushed upward and outward to accommodate the influx of people, and entirely new megacities, home to tens of millions, have sprung up.
Nowhere can this swift urban growth be seen as vividly as from space. In their new book City Unseen, geographers Karen C. Seto and Meredith Reba, experts in urbanization and global change, offer a collection of satellite images from all seven continents that exhibit the massive imprint these cities have on the landscapes around them.
“If you look at images of Las Vegas and Lagos and Shenzhen, you see how much land it takes to house billions people, and it’s astonishing,” Seto, a professor of geography and urbanization science at the Yale School of Forestry & Environmental Studies, says. “But the impact of urbanization is not only the direct land these people live on. It’s all these other non-urban places where we need to extract resources to house and electrify, to operate these cities. That’s part of the story too.”
The photos compiled by Seto and Reba have been manipulated to show near-infrared colors that delineate development and land use, offering a new perspective on the impacts of this rapid urban expansion. These images illustrate the stark differences in development on each side of international borders; the competition between urban expansion and agriculture, especially in developing nations; the way rivers can influence and define urban growth; and the way extractive industries can transform a landscape. The images also powerfully demonstrate the fragility and vulnerability of the world’s cities — striking in the face of the United Nations’ projection that there will be 2.5 billion more people living in urban centers by 2050 than today.
Shenzhen, China
February 10, 1977. Population 43,000. Landsat OLI/TIRS
February 7, 2016. Population 10.8 million. Landsat OLI/TIRS
Originally a small fishing village in southeastern China, Shenzhen was transformed when it became the country’s first Special Economic Zone in 1980 and the site of experimental economic reforms. It was China’s fastest-growing city for more than two decades, with its population exploding from 43,000 in 1977 to 10.8 million in 2016. Rice fields and fish ponds became factories and skyscrapers, and the city filled in coastal wetlands to make room for more development.
Las Vegas, Nevada, United States
April 10, 1976. Population 345,000. Landsat MSS
October 12, 2015. Population 2.27 million. Landsat MSS
Las Vegas is one of the fastest-expanding urban areas in the United States, growing from 345,000 people in 1976 to 2.27 million in 2015. The photos show the shrinking of Lake Mead [on the right side of the images], southern Nevada’s main source of drinking water, underscoring the impact of the region’s burgeoning population and development and years of intense drought.
Malé, Maldives
OrbView-3
The island of Malé, the Maldives’ capital city, packs 153,900 people into just 2.2 square miles. With an average elevation of only 7.8 feet, the city is extremely vulnerable to rising sea levels. Malé is surrounded by a massive sea wall that circles the entire island, but government officials acknowledge it will still likely be under water in the coming decades unless the world’s nations drastically reduce their greenhouse gas emissions.
Lagos, Nigeria
December 19, 1984. Population 3.29 million. Landsat TM
December 18, 2015. Population 13.1 million. Landsat OLI/TIRS
In 1881, the city of Lagos covered just 1.5 square miles and was surrounded by vast coastal wetlands. A century later, in 1984, [top photo], the population of Lagos [in brown-gray] had grown to 3.29 million people. By 2015, the megacity [bottom, in green-blue], had more than 13 million residents and covered 1,400 square miles, built on top of its historic wetlands. While Lagos, now one of Africa’s largest cities, has a thriving business and financial center, its rapid, unplanned expansion has led to severe overcrowding.
Kalgoorlie, Australia
Landsat OLI/TIRS
The town of Kalgoorlie, seen in the purple grid-like pattern in the center of the image, is home to one of the largest open pit mines in the world, stretching more than two miles and plunging nearly 2,000 feet deep. The “Super Pit,” seen here in blue, is rich in gold deposits and has transformed Kalgoorlie into a city of 30,000 people since it opened in 1989.
Jharia, India
February 23, 2017. Landsat OLI/TIRS
Jharia is home to a massive coal fire that ignited in 1916 and has been burning ever since. The city itself is small and almost indiscernible in the upper right corner of these satellite images. The land that Jharia’s nearly 82,000 residents live on is subsiding due to the fires, their homes collapsing into pits of burning coal. The image above depicts the heat of the coal fires in 2017; yellow areas are the warmest and blue are the coolest.
Manaus, Brazil
Landsat OLI/TIRS
The largest city in the Amazon, Manaus sits at the confluence of the Rio Negro, seen in dark blue, and the Rio Solimões, which appears light turquoise due to sediment that reflects the light. Situated in the heart of the world’s largest rainforest [shown in red], Manaus is a bustling port that has become a key trans-shipping point for illegal timber. The city is home to half of the population of the Brazilian state of Amazonas, with 1.8 million residents.
Mexicali, Mexico / Calexico, California, United States
Landsat OLI/TIRS
The “urban pileup” effect is evident along this stretch of the Mexico-U.S. border, which is visible about one-third of the way down this image. The contrast between densely populated Mexicali [bottom] and Calexico, both in purple, clearly demonstrates the explosive growth that has occurred in Mexican cities on the U.S. border in recent decades, as a result of free trade, a manufacturing boom, and an influx of migrants looking for economic opportunity. In 2010, Mexicali’s population was nearly 690,000, compared to Calexico’s 40,000.
Gaza City, Palestine / Ashkelon, Israel
ASTER
A conspicuous border [in the left portion of the image] divides the coastal cities of Ashkelon, Israel [north], and Gaza City, Palestine [south]. Ashkelon is surrounded by an abundance of clearly delineated agricultural plots, while Gaza City is dominated by dense urban development, shown in purple, and constrained for green space.
Minamisoma, Japan
April 7, 2009 [left] and April 6, 2011. ASTER
On March 11, 2011, the magnitude 9 Tohoku earthquake struck off the coast of northern Japan, sparking a tsunami that inundated coastal communities and led to reactor meltdowns at the Fukushima Daiichi Nuclear Power Plant complex. In places such as Minamisoma, Japan, located just north of Fukushima, it took weeks for standing water, shown in darker blue, to drain back into the ocean. The photo at left is of Minamisoma two years before the tsunami; the photo at right was taken four weeks after the tsunami. The city now has 55,880 residents — roughly 15,000 fewer than it had before the tsunami.
