The Smerdon Climate Lab is excited to welcome Yelin Jiang as a new Postdoctoral Research Scientist.  Yelin received his B.S. and M.S. in Ecology from the School of Applied Meteorology at Nanjing University of Information Science & Technology. He holds a Ph.D. in Environmental Engineering from University of Connecticut. His dissertation was advised by Prof. Guiling Wang and titled “Land-Atmosphere Interactions and Drought over Tropical South America.”

Yelin studies land-atmosphere interactions using numerical models and observational data. He is particularly interested on understanding the role of land-atmosphere interactions in drought development and hydrological change and will be working on a DOE-funded project focused on the role of vegetation in past and future global hydroclimatic change.  Yelin will be co-advised by Jason Smerdon and Richard Seager, in collaboration with the other DOE project PIs including Justin Mankin, Ben Cook, and Park Williams.

Welcome Yelin!


Check out all of our lab presentations at AGU.  They are listed below in chronological order.  Come by and say hi!


Nonlinear plant responses to carbon dioxide and climate diminish water availability

Justin Mankin, Noel Siegert, Harmanveer Singh, Emily Martinez, Zhiying Li, Jason E Smerdon, Benjamin Cook, Richard Seager, and Park Williams



Progress and uncertainties in global and hemispheric temperature reconstructions of the Common Era

Jason Smerdon and Kevin Anchukaitis



Day of rest!



A Climate and History Case Study of 18th- and 19th-Century Multidecadal Droughts in East Africa Using a new Tree-Ring Drought Atlas

Jason E Smerdon, Rhiannon Stephens, Edward Cook, and Benjamin Cook

Static Drought Assessment in a Nonstationary Climate

Zhiying Li, Justin S Mankin, Richard Seager, Jason E Smerdon, and Noel Siegert



Low-level jet dynamics simulated by CMIP6 models don’t account for their muted estimates of 20th-century precipitation trends in Southeastern South America

Arianna Varuolo-Clarke, Jason Smerdon, and Park Williams

The Smerdon Climate Lab is excited to welcome two new graduate students!  Aandishah Samara and Ibuki Sugiura joined Columbia in fall 2022 as first-year graduate students in the Department of Earth and Environmental Sciences.  Both have interests in hydroclimate variability and change and will be working on two collaborative NSF projects (here and here) aimed at understanding how variability in surface ocean temperatures, particularly those in the Pacific Ocean, impact drought patterns around the world.  Their projects will be advised jointly with Richard Seager.

Aandishah earned her B.A. in Earth System Science and M.S. in Geographical Information Systems at Clark University. Her main interests are climate change, ocean-atmosphere interactions, and applications of remote sensing. She is fascinated by the impacts of climate change on the interactions between the atmosphere and hydrosphere, and the implications for future climate risks and impacts.  Born and raised in Dhaka, Bangladesh, she is also interested in the impacts of climate change on people, especially minority communities. 

Ibuki graduated from Smith College in 2022 with B.A. in Geosciences and Mathematics. She is interested in the ocean’s role in past, modern, and future climates, and she hopes to explore the ocean-atmosphere interactions and their effects on climate change and variability using both paleo and modern data.

Welcome Aandishah and Ibuki!

Gasping salmon with infected lesions. Emaciated deer searching sagebrush flats for water. Clams and mussels boiled to death in their shells. Last summer, temperatures in the Northwest soared to record highs in the triple digits, killing more than 1 billion marine animals in the Salish Sea and stressing wildlife from the Pacific to the Rocky Mountains. Simultaneously, ongoing drought in the Southwest—which began in 2000 and is the region’s driest 22-year period in 1,200 years—is causing plants to wither, springs to dry up and wildfires to engulf entire landscapes.

The new normal is upon us—and its impacts are alarming, both for wildlife and people.

Read More

This is not a drill, or a far-flung fantasy; Southwestern US is facing a critical megadrought. The last two decades have been the driest since 800 CE, and pioneering studies by Columbia Scientists and other institutions have proven that the anthropogenic impact on the climate is a major contributing factor. The water level at the region's two largest reservoirs is at a record low, resulting in contention between seven states and millions of their residents for their diminishing share of hydroelectric power as well as agricultural and residential water demand. This is especially daunting in anticipation of the hottest period of the summer.

Please join this special session as Prof. Jason E. Smerdon, one of the authors of the recent groundbreaking article in Nature Climate Change about this megadrought discusses the unfolding crisis, its trajectory, its economic toll, and its impact on sustainability of life in the region.

Time will be allocated for Q&A.

Read More

The American southwest is in a megadrought. Water levels in lakes are dropping, threatening the local environment as well as agriculture, hydroelectric power, and the people living there. As global temperatures rise, it could be a preview of worse things to come.

Guest: Dr. Jason Smerdon, ocean and climate physicist, and Lamont research professor at the Lamont-Doherty Earth Observatory of Columbia University and co-director at the Earth Institute Faculty.

Listen to the Podcast

The National Weather Service has issued yet another warning about the dangerous heat and fire risk that will continue to grip much of the U.S. this weekend. Jason E. Smerdon, Lamont Research professor at Columbia University’s Lamont-Doherty Earth Observatory, joined Cheddar News to talk about climate change’s role in recent heat waves. “We’re seeing these kinds of events more frequently, and we’re also seeing them simultaneously around the globe," he said, "so the story of this week has been heat waves in Europe, in the United States and in parts of Asia as well, and that’s all characteristic of a globe that’s warming up.”

Read More

Record-breaking heat waves have struck many parts of the U.S., Europe, and China since the start of July, causing deaths, wildfires and glacier collapses that are likely to become a lot more common along with brutal heat.

In the U.S., hundreds of millions are experiencing a dangerous heat wave affecting 28 states as temperatures are expected to climb even above once-in-100-years levels over the next week.

China is also suffering from sweltering heat, with Shanghai hitting 40.9 C, the city’s highest temperature since 1873.


“We’re all operating within an infrastructure that we built based on at least the 20th-century climate and when you look to places like Britain much of their infrastructure was not built with the expectation that things would get this hot,” Dr. Smerdon said.

Read More

A 6-3 ruling by the Supreme Court restricting the Environmental Protection Agency’s (EPA) authority to limit power plant emissions is the latest blow to U.S. efforts to fight climate change, contributing to a renewed sense of pessimism that the U.S. political system will address the issue at the federal level.  

While the decision backed by the new conservative majority on the court does not negate efforts by state governments to take action for the planet, it puts a new limitation on the EPA.


“That’s really a shortsighted decision in light of the fact that, in terms of reducing our greenhouse gas emissions, we can’t burn what we have currently let alone create new sources,” said Smerdon. 

Read More

When Jason Smerdon heard about the Supreme Court’s ruling limiting the Environmental Protection Agency’s authority to regulate carbon dioxide emissions from power plants, the climate scientist said it felt like “a punch in the gut.”

The ruling came at a time when scientists like Dr. Smerdon say we need to be utilizing every tool available to fight climate change. The planet has already heated an average of 1.1 degrees Celsius since the Industrial Revolution, and 1.5 degrees is the threshold scientists say will result in catastrophic heat waves, increased extreme weather events and widespread species extinction.

Read More

The “megadrought” gripping the southwestern US has driven water levels at the two largest reservoirs to record lows, forcing unprecedented government intervention to protect water and power supplies across seven states.

Millions of Americans already contending with critical water shortages now face the prospect of black outs as energy demand grows during heatwaves just as hydroelectric power supply is strained. A US power regulator this week warned that a big swath of the US was at risk of blackouts, partly as a result of drought conditions curtailing hydroelectric supplies.


Jason Smerdon, a Columbia University climate scientist, described “scary” drought conditions in the south-west states.

“All emissions scenarios suggest increased warming in the south-west and therefore increased drying,” he said. Although the drought could partly be accounted for by natural variability in precipitation patterns, he explained, it was worsened by a long-term trend of aridity caused by human activity.

Read More

Beyond just the impact on other institutions, the urgency with which Columbia takes climate action bears on its educational mission, says Professor Jason Smerdon, an Earth Institute faculty member and the co-director of the undergraduate Sustainable Development program.

“For me to teach students about the importance of sustainability and then have them go out and operate on a campus that's not sustainable—that sends a message. It says that what’s being taught in the classroom isn’t as important as what happens in the ‘real world,’ or that there are financial considerations that should supersede the ethical and moral considerations of sustainability.”

Read More

Austral summer precipitation increased by 27% over the past 120 years in southeastern South America (SESA), a region including southern Brazil, Paraguay, Uruguay, and northern Argentina. This trend has driven widespread increases in agricultural production, making it important to understand if the trend will continue or reverse over the coming decades. A new paper led by Arianna Varuolo-Clarke, a 4th-year Ph.D. student in the Smerdon Climate Lab, investigates the influence of the South American low-level jet on SESA precipitation. Ari finds that a trend in this jet accounts for some of the observed rainfall increase in SESA from 1951 to 2020. Most of the jet trend comes from increased atmospheric moisture content, likely due to a combined impact of natural variations in the climate system and increased sea surface temperatures driven by human-caused global warming – a warmer ocean surface enhances evaporation, increasing humidity globally. Her results are important for understanding what is causing the rainfall trend, whether it will continue, and how we interpret climate models, which do not reproduce the observed rainfall trends in SESA over the last century or more.  

TLDR?  Check out Ari's Twitter thread on the paper.  You can also get the long version by reading the open access paper here.

The term “megadrought” is now fully ensconced in the popular vernacular when it comes to the punishing drought sweeping across much of the western U.S. over the past 22 years. So too is the figure “1200” as the number of years it’s been since a more intense 22-year drought. And experts see slim prospects of the drought’s ending at best before the end of this decade. Read More

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 United States, they are increasingly influencing the region’s water supply, and increasing the risk for flooding and landslides, according to a study published today in the Proceedings of the National Academy of SciencesRead More

Select News Coverage

Los Angeles Times