A bird’s-eye view of history

Iconic aerial photo archives from the UCLA Department of Geography are a rich resource for researchers and the public

UCLA Geography Aerial Archives

UCLA Geography Aerial Archives

By Jonathan Riggs

Today, anyone with a drone can capture dazzling images of the Earth below. But it wasn’t so long ago that would-be aerial photographers had to swing nearly 50-pound aerial cameras out of single-engine plane windows to do the same. The UCLA Department of Geography owns a huge number of such images in its Benjamin and Gladys Thomas Air Photo Archives, many of which detail California life and landscapes as far back as 1920. These remarkable images are as valuable artistically as they are historically.

In fact, the department has launched a new website featuring images from two of its collections, which are among the world’s best. Breathtaking images of Los Angeles and New York City—everything from a gorgeously moody shot of clouds over Manhattan on Oct. 15, 1931 to a view of UCLA and Westwood on Jan. 13, 1950—are available to purchase as fine art prints.

“The department was given these collections and has been maintaining them as best as possible for decades. However, some of the negatives are now over 100 years old and deserve better long-term treatment than we can give them,” says department chair Greg Okin. “Proceeds from the sale of images will allow us to preserve the physical images for posterity. It will also allow us to digitize them in order to ease access to the collection for generations to come.”

Overall, the Aerial Archives contain 120,000 black and white negatives, 100,000 black and white prints, and several hundred color images. What makes these collections so special is that they are exclusively oblique aerial photos, meaning they were taken from the side, rather than looking straight down as on a Google map. This angle captures a richness of detail that allows viewers to read signs, identify specific cars and even see what people were wearing.

UCLA Geography Aerial Archives

UCLA Geography Aerial Archives

In addition to bringing the past to vivid life for members of the public, these archives are an incredible scholarly resource.

“We have students and faculty across the university as well as people in many industries who use this unique resource for their research,” Okin says. “We can see, for example, the development of the Los Angeles River as it was channelized. We can identify areas of beach erosion. We can see how specific areas of Los Angeles have changed through time. We can see how the city developed into the complex place that it is now as well as map the legacies of policies and attitudes in the region. The potential uses are endless.”

Another devoted user of the Archives is Kelly Turner, assistant professor of Urban Planning and of Geography and co-director of the Luskin Center for Innovation. She’s leading a multifaceted project to explore how the racist policy of redlining—and hundreds of other seemingly unrelated and everyday actions by homeowners and developers alike—caused the L.A. neighborhood of Watts to become nearly 5 degrees Fahrenheit hotter than the overall city average.

“Our project aims to use innovative, interdisciplinary methods to say what land change occurred, why and how much it changed the temperature,” Turner says. “We hope to arm the community of Watts with data, and to enable them to pinpoint specific elements that can be effectively changed.”

UCLA Geography Aerial Archives

UCLA Geography Aerial Archives

Turner and her team, which includes anthropologist Bharat Venkat collecting oral histories and historian Marquis Vestal with expertise in the intersection of race and land transactions, are using the Archives to create a painstakingly accurate model of historic Watts over the years. By simulating the built environment so accurately, they are able to replicate the past microclimate conditions and determine how the temperature felt for the average citizen on the street on a given day.

“This project wouldn’t be possible without these archives. We need to know the exact placement of features like walls and sidewalks to build the model,” Turner says. “This high resolution imagery allows us to revisit a place with methods that were not available in the 1920s or ’50s to glean new insights that are relevant to contemporary debates about heat and environmental justice.”

“Archival photos reveal the history of planning decisions,” adds Tiffany Rivera, an urban and regional planning graduate student who is assisting on the project. “I look at these images to inform more sustainable and equitable urban designs.”

It’s fitting that these collections landed at UCLA: Los Angeles was a nexus for early aerial photography, and early motion pictures used aerial photography starting in the 1920s. These two iconic industries essentially grew up together just a few miles from campus, making the Archives especially meaningful for the UCLA community.

“We invite anyone interested to check out this incredible world-class resource, either on our website or to reach out and make an in-person visit,” says Okin. “It’s a remarkable opportunity for everyone to see what the collection, and UCLA, have to offer while also providing the chance to own beautiful pieces of history.”

For more of Our Stories at the UCLA College, click here.

Forest fires increasingly affecting rivers and streams – for better and worse

An image of the Bitterroot River Montana forest fire

Bitterroot River Montana forest fire. Image credit: John MacColgan/Creative Commons

UCLA-led study finds greater ‘streamflow’ may mean more water for the West, but could increase risk for floods, landslides

By Anna Novoselov

Forest fires can have a significant effect on the amount of water flowing in nearby rivers and streams, and the impact can continue even years after the smoke clears.

Now, with the number of forest fires on the rise in the western U.S., that phenomenon is increasingly influencing the region’s water supply — and has increased the risk for flooding and landslides — according to a UCLA-led study published today in the Proceedings of the National Academy of Sciences.

Researchers examined streamflow — a measure of water volume over time in rivers and streams — and climate data for 179 river basins. (Basins are areas of land where precipitation collects and drains into a common outlet.) All of the areas were located in the western U.S., and all had been affected by forest fires between 1984 and 2020.

Using a mathematical model they developed, the scientists discovered that streamflow in the years after a fire tended to be higher than scientists would expect based solely on climate conditions, and that larger fires tended to be followed by larger increases in streamflow.

In basins where over 20% of the forest had burned, streamflow was 30% greater than expected based on climate conditions, on average, for an average of six years.

Park Williams, a UCLA associate professor of geography and the study’s lead author, said forest fires enhance streamflow because they burn away vegetation that would otherwise draw water from soil and block precipitation before it ever reached the soil. Intense forest fires can also “cook” soils, making them temporarily water repellent.

From 1984 through 2020, the amount of forested area burned each year in the West increased elevenfold, and that trend is expected to continue or even accelerate due to climate change.

“As a result, we’re starting to see sequences of years when large portions of forest are burned across some very important hydrological basins such as those in California’s Sierra Nevada,” Williams said.

The study’s findings suggest that wildfires will soon become yet another important consideration for those in charge of the supply and distribution of water resources. Each year, the region’s water managers must carefully calculate how much water will be available and determine how to conserve and allocate it.

In one sense, the increase in streamflow from forest fires may be beneficial, Williams said.

This could come as good news to dry cities like Los Angeles, because it could actually enhance water availability,” Williams said.

But other outcomes could be troubling. For example, in the coming decades, too much water could overwhelm reservoirs and other infrastructure, and could increase the risk for catastrophic flooding and landslides in and around burn areas.

To adapt to increasing flood risks, Williams said, water managers in California may have to lower the water levels in reservoirs in the fall and winter to make room for excess water from major rainfall and snowstorms. Such a strategy could avoid disastrous flooding in some cases, but it could also put communities at risk for having too little water during the state’s increasingly hot, dry summers.

Water after a forest fire also tends to be heavily polluted, carrying mud, debris and large sediment loads. So even if the quantity of available water increases after a large fire, it’s likely that water quality will worsen.

Williams said he hopes the findings help water managers and climate scientists make better predictions about water availability and flood risk.

“Water is a really heavy and destructive thing,” Williams said. “It’s great when it comes to us in the expected amount. It is catastrophic when it shows up unexpectedly.”

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

Megadrought in southwestern North America is region’s driest in at least 1,200 years

Image of parched land in Nevada

Parched land in Nevada. A UCLA-led research team studied centuries of megadroughts in the region spanning southern Montana to northern Mexico and the Pacific Ocean to the Rocky Mountains. Photo credit: Famartin/Wikimedia Commons

Climate change is a significant factor, UCLA-led research finds

By Anna Novoselov

The drought that has enveloped southwestern North America for the past 22 years is the region’s driest “megadrought” — defined as a drought lasting two decades or longer — since at least the year 800, according to a new UCLA-led study in the journal Nature Climate Change.

Thanks to the region’s high temperatures and low precipitation levels from summer 2020 through summer 2021, the current drought has exceeded the severity of a late-1500s megadrought that previously had been identified as the driest such drought in the 1,200 years that the scientists studied.

UCLA geographer Park Williams, the study’s lead author, said with dry conditions likely to persist, it would take multiple wet years to remediate their effects.

“It’s extremely unlikely that this drought can be ended in one wet year,” he said.

The researchers calculated the intensity of droughts by analyzing tree ring patterns, which provide insights about soil moisture levels each year over long timespans. (They also confirmed their measurements by checking findings against historical climate data.) Periods of severe drought were marked by high degrees of “soil moisture deficit,” a metric that describes how little moisture the soil contains compared to its normal saturation.

Since 2000, the average soil moisture deficit was twice as severe as any drought of the 1900s — and greater than it was during even the driest parts of the most severe megadroughts of the past 12 centuries.

Studying the area from southern Montana to northern Mexico, and from the Pacific Ocean to the Rocky Mountains, researchers discovered that megadroughts occurred repeatedly in the region from 800 to 1600. Williams said the finding suggests that dramatic shifts in dryness and water availability happened in the Southwest prior to the effects of human-caused climate change becoming apparent in the 20th century.

Existing climate models have shown that the current drought would have been dry even without climate change, but not to the same extent. Human-caused climate change is responsible for about 42% of the soil moisture deficit since 2000, the paper found.

One of the primary reasons climate change is causing more severe droughts is that warmer temperatures are increasing evaporation, which dries out soil and vegetation. From 2000 to 2021, temperatures in the region were 0.91 degrees Celsius (about 1.64 degrees Fahrenheit) higher than the average from 1950 to 1999.

“Without climate change, the past 22 years would have probably still been the driest period in 300 years,” Williams said. “But it wouldn’t be holding a candle to the megadroughts of the 1500s, 1200s or 1100s.”

As of Feb. 10, according to the U.S. Drought Monitor, 95% of the Western U.S. was experiencing drought conditions. And in summer 2021, according to the U.S. Bureau of Reclamation, two of the largest reservoirs in North America — Lake Mead and Lake Powell, both on the Colorado River — reached their lowest recorded levels.

Regulators have continued to implement water conservation measures in response to water shortages caused by the drought. In August, for example, federal officials cut water allocations to several southwestern states in response to low water levels in the Colorado River. And in October, California Gov. Gavin Newsom declared a drought emergency and asked Californians to voluntarily decrease their water usage by 15%.

Williams said initiatives like those will help in the short term, but water conservation efforts that extend beyond times of drought will be needed to help ensure people have the water they need as climate change continues to intensify drought conditions.

The study was a collaboration among researchers from UCLA, NASA and the Columbia Climate School.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

Politics of place still exerts powerful influence in voting booth

John Agnew, UCLA distinguished professor of geography, has spent his scholarly career examining the politics of place. He teaches courses in political geography and globalization, as well as sections in the department of Italian.

UCLA faculty voice: The One-China policy benefits China, Taiwan and the United States

Although Trump’s questioning the “One China” policy may seem like a quick and clever way to get China’s attention, this decades-old policy’s ambiguity actually benefits United States, China and Taiwan.

Pacific Ocean’s response to greenhouse gases could extend California drought for centuries

Clues from prehistoric droughts and arid periods in California show that today’s increasing greenhouse gas levels could lock the state into drought for centuries, according to a study led by UCLA professor Glen MacDonald.

Archaeologists and geographers team to predict locations of ancient Buddhist sites

In a study published this week in Current Science, archaeologist Monica Smith and geographer Thomas Gillespie identified 121 possible locations of what are known as Ashoka’s “edicts.”

Social Science students travel the globe in the name of research

UCLA Geography and Political Science student Logan Linnane isn’t having a typical summer.

The fourth-year student is spending his break in the communities that border the Ban Mai Nai Soi refugee camp in Northern Thailand, where a diverse group of international organizations provides aid to Karenni refugees from Myanmar.

The recipient of an Irving and Jean Stone Research Award, Linnane is conducting original research on the vocational environmental education programs made available to refugees by aid organizations. The field work is enabling him to explore the effectiveness of these environmental education programs from the perspectives of those they seek to serve.

This kind of opportunity is a key facet of a revolution unfolding within higher educational practice that Honors Program Assistant Vice Provost G. Jennifer Wilson characterizes as “teaching people to become the thing you want them to learn, rather than telling them what you want them to learn.”

While the UCLA College Honors Program distributes its summer stipends to 22 honors students throughout the College, Wilson says that students in the social sciences are particularly well prepared by their faculty to write and conduct compelling research proposals. They make up a large proportion of grantees each year. Seven students traveled abroad this year, including to Iran, China and Germany.

While Linnane’s research is connected to his Honors Thesis, he’s also thinking of the broader impact.  He hopes that his work “will serve as a potential resource for environmental organizations as they continue to adjust and improve the curricula for programs that serve communities of displaced people.”

Professor Eric Sheppard, Linnane’s faculty advisor in the Geography Department, said the research his student is doing this summer is furthering Western scholars’ understanding of Myanmar and the topic of refugees in general.

Recipients must be part of the College Honors Program or a departmental honors program. Preparation is intense: students work closely with a faculty advisor and are required to gain Internal Review Board approval, a process most students don’t encounter until the graduate level.

But the hard work is worth it.

“It’s easy to sit on campus and dream about working in the developing world, but planning a project and living amongst the communities you strive to work with is truly the only way to even remotely understand what a career in development entails,” Linnane said.

Sheppard personally meets with his undergraduate researchers several times to help them develop appropriate research questions and methodologies.

“We talk about whether they need language skills and how to acquire these,” he said. “We discuss the country itself so they appreciate what they will be faced with. We set up a procedure for adjusting the research design if necessary. I also discuss with them basic travel preparations such as vaccinations, medicines to have with them, travel insurance, and what to do in an emergency.”

Honors Program research stipends are supported by four private donors. Despite this generous support, the need is growing as global knowledge becomes increasingly important.

“All undergraduates need to broaden their understanding of and perspective on the world if they are to become thoughtful world citizens,” Sheppard said. “The opportunity to do research on the ground, to be thrown into a situation where you work with locals and learn their views, is a vital opportunity that should be utilized more than it is.”