Is this the new stormy climate James Hansen warned about? Investigate extreme rain and flash floods with expert Jonathan Gourley from NOAA National Severe Storms Laboratory. But Australian climate lecturer Andrew King cautions not all floods are sure signs of global warming. Then my report about insidious smog killing millions every year, starting in the womb. I’m Alex. Welcome to Radio Ecoshock.

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Without warning, flash floods wash cars away, as roads become rivers. You can’t miss those videos popping up all over the world: Spain, Las Vegas, Brazil, Hong Kong, Turkey, Shanghai, the Netherlands, Greece (with three exclamation marks) and then parts of East Libya washed away, thousands dead – all this in just the first two weeks of September. A year’s worth and even three year’s of rain falling in a day. What is happening? Is this a new twist on climate change?

Searching for experts on extreme rain and flash floods, Jonathan Gourley comes in the top tier. With over 50 co-authored papers, Dr. Gourley is a Research Hydrologist at the NOAA/National Severe Storms Laboratory in Oklahoma. Gourley is also Adjunct Associate Professor at the University of Oklahoma School of Meteorology. He is author or co-author of 50 peer-reviewed papers on weather, climate, and the science of prediction.


Download or listen to this 30 minute interview with Jonathan Gourley in CD Quality (57 MB) or Lo-Fi (14 MB)



Rains that might not be big in the East, can cause flash floods when they encounter a burn scar. As soon as rains fall on the scar, the response and rising water levels can be just MINUTES later. Landscape damage can be very large. Debris and boulders, trees swept away with only an inch and half of rain. Practically none of the rain penetrated the soil. Not much help with drought.


In June 2022, Gourley co-authored a paper about U.S. floods… “Current status and forecast under a future warmer climate”.

We found: (a) an overall increase in flood frequency (+101.7%) and spatial extent (+44.9%), mainly attributed to more extreme rainfall and variability in the future; (b) weakening rainfall and flood seasonality, resulting in more random and unpredictable events throughout the year; (c) earlier flooding season onsets in the West and snow-dominated regions while delayed onsets in the East driven by drier antecedent soil moisture; (d) correlation between extreme rainfall and flood onsets is becoming stronger in the West yet weaker in the East in the future.”

Overall flood frequency increases 100% covering 44% more area with “more random and unpredictable events throughout the year.” That sounds as serious as sea level rise and the heat waves.


A paper published in March 2021, led by Nikolaos Christidis, said this about the United Kingdom’s prospects:

”Compared to a hypothetical natural climate, we estimate a 10-fold increase in the chances of such extreme rainfall events in the United Kingdom by the end of this century, which underlines the need for effective adaptation planning.”


In an article, my friend Judy Deutsch writes:

On July 13, 2023, James Hansen wrote that the Earth is heading into a new frontier of global climate in which ‘the moisture extremes are more important than the temperature extremes.’ … Hansen writes: ‘higher absolute humidity and deeper penetration of moist convection cause a larger portion of the rainfall to occur in intense thunderstorms.’” Hansen called his book “Storms of My Grandchildren”.

You can watch Dr. Gourley in this a presentation two years ago on “Post-Wildfire Hydrometeorlological Observations and Forecasts”.




A study based on U.S. data…


Research Article Earth, Atmospheric, And Planetary Sciences Open Access

Human influence has intensified extreme precipitation in North America

Megan C. Kirchmeier-Young and Xuebin Zhang  June 1, 2020


Research Article Atmospheric Science

Increasing precipitation variability on daily-to-multiyear time scales in a warmer world

Wenxia Zhang , Kalli Furtado , Peili Wu, Tianjun Zhou , Robin Chadwick , Charline Marzin , John Rostron , And David Sexton   Science Advances 28 Jul 2021

There is a (possibly paywalled) article on this paper here.




Streets turn to violent rivers, houses flood – even in desert areas – social media is filled with apocalyptic scenes of extreme rainfall this year. In the first week of September, Hong Kong “recorded its heaviest hourly rainfall on record with 158.1 mm [6.2 inches] between 11 PM and midnight.” Epic rains fell in Spain, Greece, Turkey, Bulgaria, and Brazil and yes, Burning Man. But is it all due to global warming?


Andrew King is Senior Lecturer in Climate Science at The University of Melbourne. He says “climate change isn’t always to blame for extreme rainfall”. Andrew led a new paper in Nature Geoscience to explore what is and is not happening here.


Download or listen to this 15 minute interview with Andrew King in CD Quality


This interview was stimulated by this paper by Andrew King et al: “Communicating the link between climate change and extreme rain events”. That was published in Nature Geoscience July 6, 2023.

We usually associate cloudy, rainy, and windy sort of weather with low pressure systems. The TV weather person shows them on a map. In Andrew’s article in The Conversation, he talks about how climate change impacts low pressure systems.

As climate communicators, we struggle with that adage “we can’t attribute any one event to climate change”. That’s being replaced with attribution studies that pinpoint climate influence. But Andrew’s caution sounds different. His work shows a relatively simple rule of thumb to know what probably is or is not climate changes with extreme rain events. In a nutshell: those rapid, flash-flood events are easier to attribute to climate change. But long rainy storms hovering over the landscape, forcing river flooding, may have other causes not directly related to climate change. Two types of floods with two different drivers.

I also ask Andrew King about another of his 2023 papers: “Climate change emergence over people’s lifetimes”. Our perception of climate change varies with age group.



Perhaps you were not listening to Radio Ecoshock in early 2006. I’m going to replay my quick report on killer smog, just as true today. This will also prepare you for an upcoming program asking the question: if we clean up the air, will that add more warming to trigger tipping points. Is it too late for clean air?

Listen to or download this 21 minute replay feature on smog and your health in CD Quality


By the way, Dr. Frederica Perera is still at it, watching over air pollution and our health. In 2021 she published the paper “Potential health benefits of sustained air quality improvements in New York City: A simulation based on air pollution levels during the COVID-19 shutdown.”

I’m Alex Smith. Thank you for listening, and caring about our world.

Please support Radio Ecoshock if you can. Listener donations keep this blog ad-free, and the program free for 106 radio stations and online listeners around the world. You can help this keep going!