Climate & Environment

Report paints grim picture of how nuclear war could impact oceans

Yvaine Ye — Mon, 28 Jul 2025 13:00:00 +0000

Report paints grim picture of how nuclear war could impact oceans Yvaine Ye Mon, 07/28/2025 - 07:00

Yvaine Ye

Recent conflicts in Europe and the Middle East have reignited fears about the use of nuclear weapons. What would a nuclear conflict do to the planet鈥檚 environment today?

In a new congressionally mandated report, oceanographer Nicole Lovenduski, who directs 探花视频鈥檚 Institute of Arctic and Alpine Research (INSTAAR), outlined the dangerous fallout a nuclear war could bring, from firestorms and global cooling to ecosystem collapse and potentially irreversible ocean disruption.

Nicole Lovenduski/探花视频

鈥淭he ocean makes up three-quarters of our planet's surface,鈥� said Lovenduski, a professor in the Department of Atmospheric and Oceanic Sciences. 鈥淜nowing how the ocean responds to changes in the environment is really important, because it can influence the global climate system.鈥�

To date, the only use of nuclear weapons in conflict occurred in 1945, when the United States dropped two atomic bombs on Japan. At the time, scientists were not tracking the environmental impact.

According to Lovenduski鈥檚 previous research, nine nations possess more than 13,000 nuclear weapons in the world, with the United States and Russia controlling the most operational nuclear weapons. The stockpiles in countries including India, Pakistan, China, and North Korea have also increased in the past eight decades.

Compiled by dozens of scientists across the country, the report aims to reevaluate the long-term environmental impacts of nuclear war using the latest scientific evidence.

鈥淲hat we learned in writing the report was that we need additional scientific research to adequately describe the potential environmental and climate consequences of a nuclear conflict. But we know enough to know that a nuclear war would be a horrific outcome for humanity,鈥� Lovenduski said.

探花视频 Today sat down with Lovenduski to discuss how a nuclear conflict could change the ocean and why those changes are important.

What happens when a nuclear weapon is detonated?

Hypothetically, if there were to be a large-scale nuclear conflict on this planet that starts a lot of fire, there could be a firestorm that releases a lot of soot into the atmosphere. If it makes it all the way up into the stratosphere, where the air flow tends to be more stable, soot can stay there for a really long time and encapsulate the entire planet. That will lead to a dramatic reduction in the amount of sunlight that comes into our planet.

Without sunlight, we cannot have photosynthesis. Photosynthetic organisms, like plants on land and algae in the ocean, form the base of the food web for everything else. Without photosynthesis, we cannot have a source of food.

What would happen to the ocean, specifically?

If a lot of soot gets up into the stratosphere and blocks sunlight, it would cool the planet suddenly and significantly. That's where the concept of nuclear winter first arose many decades ago.

Sea ice could extend all the way down to places in the Pacific and Atlantic that don't currently have ice. That would affect how ocean currents move and whether surface seawater can sink and slow down large-scale circulation.

We may no longer have, for example, the Gulf Stream, bringing warm water northwards into the Atlantic, resulting in dramatic cooling of Northern Europe. Ocean currents are important in making sure many parts of the world are habitable for many.

Would people living far from coastal zones be impacted?

As a result of nuclear winter, crops on land could fail. We might look to the ocean for a source of food. But if the fish don鈥檛 have anything to eat, we鈥檙e all going to starve. So even if there's a conflict, and it doesn't affect us directly where we live, the global population is at risk of starvation.

How long would it take for the ocean to recover?

The atmosphere moves pretty fast. If the soot above the Middle East enters the stratosphere, it can spread globally within one to two years.

But the ocean moves really slowly. When water sinks in the North Atlantic, it can take hundreds, if not thousands, of years for that water to reemerge. So if you perturb the ocean, it can take a long time to recover. In some of the computer simulations we did, the simulation stopped before we even saw that recovery happen, because we were out of computing time. So we never saw the ocean recover in our simulations, which is scary.

I hope we don't ever go down this road. I hope that the people in charge of deciding whether or not to engage in nuclear conflict can learn from some of the work that we have done. I hope that the report leads to a world where there is no nuclear conflict.

探花视频 Today regularly publishes Q&As with our faculty members weighing in on news topics through the lens of their scholarly expertise and research/creative work. The responses here reflect the knowledge and interpretations of the expert and should not be considered the university position on the issue. All publication content is subject to edits for clarity, brevity and university style guidelines.

A new congressionally mandated report by a CU oceanographer warns that the use of nuclear weapons could collapse ocean ecosystems, trigger global climate disruptions and put billions at risk of starvation.

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Mushroom cloud above Nagasaki after atomic bombing on August 9, 1945. (Credit: Charles Levy/Wikimedia)

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Mushroom cloud above Nagasaki after atomic bombing on August 9, 1945. (Credit: Charles Levy/Wikimedia)

Where does your food come from? First-of-a-kind map tracks journey across thousands of miles

Yvaine Ye — Thu, 24 Jul 2025 16:17:42 +0000

Where does your food come from? First-of-a-kind map tracks journey across thousands of miles Yvaine Ye Thu, 07/24/2025 - 10:17

Yvaine Ye

If extreme rainfall wiped out all food growing in Jalisco, a Pacific coastal state in western Mexico, it would eliminate enough calories to feed 765,000 people in the United States. A widespread drought in the Brazilian state of Paran谩 could cut enough fat to meet needs of more than 1.7 million people in Egypt. Western Australia鈥檚 next major heatwave could knock out enough protein to feed 8 million people in China.

These are some of many insights revealed by a newly launched interactive tool called the Global Food Twin. Developed by 探花视频 data scientist Zia Mehrabi and his collaborators at Earth Genome, a non-profit organization, the interactive digital map shows how food moves from farm to table. It offers a first-of-its kind view into the world鈥檚 highly connected and increasingly fragile food system.

Explore the global food twin

鈥淭his is a landmark effort, because no one鈥檚 ever done this at this scale and level of detail,鈥� said Mehrabi, assistant professor of environmental studies and founder of 探花视频鈥檚 Better Planet Laboratory, which leverages data science to address some of the leading global environmental and human rights issues. 鈥淲e鈥檙e able to represent the complexity of our food system, showing people a window into a world they haven鈥檛 seen before.鈥�

As climate change continues to put pressure on global food production and supply chains, the team hopes the data could help countries better anticipate and prepare for disruptions like droughts and floods, ensuring communities maintain food access in the face of hazards.

Food hubs

The team built the map using data on agricultural yields of common foods鈥攊ncluding grains, meats and vegetables. They also accounted for consumer demand, trade records, transportation networks, and satellite ship-tracking data from around the world.

With the Global Food Twin, users can look up how common agricultural food groups, from grains to oil to fresh produce, travel from where they鈥檙e produced to consumers in more than 3,700 states and provinces across 240 countries. The team also calculated the calories and essential nutrients, such as protein and iron, that flow through the trades.

Zia Mehrabi (Credit: Patrick Campbell/探花视频)

The map is an expansion on Mehrabi鈥檚 pioneering project visualizing the U.S. food system. It revealed that just 5.5% of U.S. counties produce half of the nation鈥檚 crops.

The global version paints a similar picture. Only 1.2% of sub-national administrative units, such as states, provinces and districts, supply 50% of the world鈥檚 grains.

For example, India鈥檚 Uttar Pradesh supplies 17 gigatons of grains annually. Together with other food products the state grows, Uttar Pradesh alone provides enough calories for more than 22 million people, including close to half a million in the United States.

鈥淢any people think the U.S. can stand alone when it comes to food supply, and we can call the shots on trade agreement. But this map illustrates that even a powerhouse like the U.S. relies heavily on imports,鈥� Mehrabi said, adding that many food items that Americans enjoy daily almost all come from other countries.

Take bananas. Almost every banana in U.S. grocery stores comes from countries like Guatemala, Ecuador and Mexico. Coffee, aside from a small amount grown in Hawaii, mainly comes from Brazil, Colombia and Vietnam.

鈥淭his map shows very clearly how connected we are with each other when it comes to food, something many consumers don鈥檛 think about when they鈥檙e eating a banana,鈥� Mehrabi said.

Choke points

The map also highlights the growing vulnerability of global food systems to climate change. Many critical trade corridors, such as the Mississippi River and the Rhine River in Europe, have experienced low water levels this summer, stranding ships and disrupting food transportation.

Certain globally traded crops are also under threat. Studies estimate that by 2080, rising temperature, extreme weather and climate-related pests could slash the areas suitable for growing bananas by 60%. Climate change could also reduce coffee yields in the Americas by 70%.

Mehrabi said the Global Food Twin enables researchers and policymakers to model the impact of these climate hazards on the food system.

鈥淚f, say a heatwave hit the Midwest and, at the same time, the Mississippi River slowed because of drought, where are the communities that would feel the biggest impact? We haven鈥檛 really been able to track how disruptions could ripple through the food system until now. This dataset lets us start asking those questions,鈥� Mehrabi said.

He added that low-income households already facing food insecurity are the most vulnerable to production or supply chain disruptions, because even small shocks in the system can trigger dramatic food price spikes.

When food prices rise, policy-makers can use stimulus payments and other dignity-focused safety nets to improve purchasing power for vulnerable communities, according to Mehrabi.

鈥淭his is a critical window into how climate change can collide with trade infrastructure, labor needs and food production. For the first time, we can start visualizing how that plays out on a global scale,鈥� Mehrabi said.

A new interactive tool exposes the fragile, interconnected web of global food trade鈥攁nd how climate change could disrupt it.

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CUriosity: In the wake of Texas floods, how do emergency alerts work, and where do they fall short?

Daniel William Strain — Tue, 22 Jul 2025 16:37:06 +0000

CUriosity: In the wake of Texas floods, how do emergency alerts work, and where do they fall short? Daniel William鈥� Tue, 07/22/2025 - 10:37

Daniel Strain

In CUriosity, experts across the 探花视频 campus answer pressing questions about humans, our planet and the universe beyond.

This week, Carson MacPherson-Krutsky, a research associate at the Natural Hazards Center at the University of Colorado Boulder, answers: 鈥淗ow do emergency alerts work, and where do they fall short?鈥�

Aftermath of the deadly flooding that devastated Central Texas in July 2025. (Credit: CC photo by World Central Kitchen via Flickr)

In the early hours of July 4, flash floods rose through parts of Texas鈥� Kerr County and surrounding regions, killing more than 130 people, including 27 children and counselors at a local summer camp.

In the wake of the disaster, numerous media reports raised questions about whether residents had enough warning to make it to safety.

Carson MacPherson-Krutsky knows how important timely emergency alerts are for people in the path of natural hazards like floods, wildfires, tornadoes and more. She鈥檚 a research associate in the Natural Hazards Center at 探花视频 and has investigated emergency alert systems in Colorado. Simply put, she said: They鈥檙e all over the place.

Carson MacPherson-Krutsky

鈥淭he biggest takeaway is that it鈥檚 complicated,鈥� said MacPherson-Krutsky, a geologist and social scientist by training who studies how to communicate risk and help people prepare for natural disasters. 鈥淭here are multiple systems at work, and they vary from municipality to municipality.鈥�

In a report published in 2024, MacPherson-Krutsky and her colleagues surveyed 222 officials from 57 of Colorado鈥檚 64 counties about their emergency alert systems. The research was funded through a bill passed by the state legislature.

One of the most basic kinds of disaster warnings, she said, are wireless emergency alerts (WEAs). These text messages go directly to the phones of people located in a particular geographic area. Amber Alerts for abducted children use the same system. (You may be familiar with the blaring beeps and vibrations that accompany these messages).

A wide range of government groups, both local and national, can send out WEAs in the event of natural disasters or acts of violence. Personnel need to take a training, and they work through a system administered by the U.S. Federal Emergency Management Agency (FEMA) and its partners.

Before dawn on July 4, for example, the National Weather Service (NWS), which is part of the U.S. National Oceanic and Atmospheric Administration (NOAA), sent out several such text alerts. According to The Texas Tribune, one alert at 4:03 a.m. local time urged recipients to 鈥淪EEK HIGHER GROUND NOW!鈥�

Beyond WEAs, alerts get more complicated.

In Colorado, for example, every county tends to have its own alert system, which can be managed by a wide range of groups鈥攆rom sheriff鈥檚 offices to fire departments and 911 call centers. They may send out warnings over text messages, social media, TV and radio, word of mouth or even sirens. In many cases, residents have to sign up or download an app to receive messages.

Previously in CUriosity

Are sharks really as scary as their reputation?

Or read more CUriosity stories here

鈥淒epending on who's sending the alert, they have different procedures and protocols in place for what triggers an alert, who sends it, what approvals are needed and so on,鈥� MacPherson-Krutsky said.

Those disparities become especially glaring for people with disabilities or who speak languages other than English, MacPherson-Krutsky added. Currently, the WEA technology can only support messages in English and Spanish. The federal government has made moves to expand the languages available, but she noted that a recent executive order from the Trump administration could make those changes harder to enact. In Colorado, more than one-third of the emergency personnel the researchers surveyed didn鈥檛 know if their emergency alert systems had the ability to translate to other languages or alert people who are deaf.

鈥淭hat creates a lot of inequity,鈥� she said. 鈥淎 deaf person living in one county might receive an alert, but their brother who lives across the border wouldn鈥檛.鈥�

In their report, MacPherson-Krutsky and her colleagues recommended that Colorado adopt a single, state-wide system for sending out emergency alerts. Connecticut, Florida and Oregon have such a system, which counties or other localities can use at no cost to them.

She added that federal and state funding is critical for sending timely alerts in the event of natural disasters. The White House鈥檚 proposed budget for 2026 includes a more than 25% cut in funding for NOAA.

鈥淣atural hazards researchers are worried about what these cuts would do to public safety,鈥� MacPherson-Krutsky said. 鈥淥ur colleagues at NOAA and the National Weather Service are doing such amazing work to make these warnings better. And if some of them aren鈥檛 there to advance this research, we鈥檒l all bear the consequences of that.鈥�

When natural disasters strike, people across the United States often depend on timely warnings to get to safety. But in Colorado and many parts of the country, these alerts are a patchwork that vary from county to county.

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Waleed Abdalati to testify July 16 at congressional hearing

Yvaine Ye — Tue, 15 Jul 2025 13:00:00 +0000

Waleed Abdalati to testify July 16 at congressional hearing Yvaine Ye Tue, 07/15/2025 - 07:00

Waleed Abdalati, a professor of geography and director of the Cooperative Institute for Research in Environmental Sciences (CIRES) at 探花视频, is scheduled to testify on July 16 at 8:00 AM MT before the Environment Subcommittee of the U.S. House Science, Space and Technology Committee.

CIRES is the oldest and largest of the national network of Cooperative Institutes at the National Oceanic and Atmospheric Administration (NOAA).

The hearing, titled 鈥淧rotecting Lives and Property: Harnessing Innovative Technologies to Enhance Weather Forecasting,鈥� will examine emerging technologies for weather data collection. It will discuss how using diverse data sources can greatly improve the accuracy and timeliness of weather forecasting.

Watch the livestream here

Waleed Abdalati, a climate scientist and director of the Cooperative Institute for Research in Environmental Sciences, is scheduled to testify before the House Science, Space and Technology Committee. Watch via livestream.

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Why flood prediction in the US falls short and how researchers are working to fix it

Yvaine Ye — Mon, 14 Jul 2025 19:08:40 +0000

Why flood prediction in the US falls short and how researchers are working to fix it Yvaine Ye Mon, 07/14/2025 - 13:08

Yvaine Ye

Dangerous floods struck communities across the United States this July.

Heavy rains in New York region killed at least two people after swamping roads and rails this week. In New Mexico, a flash flood hit a mountain town, killing three people. Torrential rain from a tropical storm destroyed homes and claimed at least four lives in North Carolina.

In Texas, over the July 4 holiday weekend, catastrophic floods swept through the central part of the state, claiming the lives of at least 120 people, including more than two dozen children.

Even with advances in technology, forecasting how much rain will fall, where it will land and the impact of flooding all remain difficult, according to Zhi Li, a researcher at 探花视频鈥檚 Institute of Arctic and Alpine Research.

Zhi Li

鈥淚n Texas, different weather forecasting models were giving out different predictions,鈥� said Li, an assistant professor in the Department of Civil, Environmental and Architectural Engineering, who uses computer models to simulate floods and forecast risk. 鈥淚t wasn鈥檛 until just a day before heavy rain began to inundate the area that the models finally agreed there would be extreme precipitation. That left very little time for people to respond.鈥�

探花视频 Today sat down with Li to discuss where the current flood prediction system falls short and what鈥檚 being done to meet the urgent need for real-time flood forecasting.

How does the official current flood prediction system work?

The National Weather Service (NWS) is the primary government agency responsible for issuing weather forecasts and warnings in the United States. Currently, flash flood forecasting is mainly based on the amount of rainfall expected in a given region. If the predicted rainfall is likely to exceed a certain threshold and overflow riverbanks, streams or dams in the area, the NWS will issue a flash flood warning.

Where does this system fall short?

The current system can only predict where the floods might happen, but it doesn鈥檛 provide detailed information about how much water could overflow onto land, how far it will spread or how deep the flooding might get.

Without the data, it鈥檚 hard to know where exactly the danger is and who should evacuate. As a result, it offers little urgency or actionable information for residents.

Is there a better way to predict floods?

At my newly established Flood Lab at 探花视频, we鈥檙e working on developing accurate, high-resolution flood models, which are computer programs that predict how water will behave during flood events. Our latest model can predict flooding impacts at one-meter resolution, meaning we can pinpoint exactly where water will go and how deep it will get. Running these models is very computationally expensive, which is why the National Weather Service doesn鈥檛 have real-time flood models currently in use.

We鈥檙e developing a flood prediction model powered by artificial intelligence that also follows the physical laws governing how water moves. This will significantly speed up forecasting compared to traditional flood models.

Can we prevent damage from these increasingly common, record-breaking weather events?

We need to be aware that climate change is making extreme weather events more frequent, and that鈥檚 why deploying a real-time flood model is very necessary. It would be able to tell us with more confidence where the vulnerable regions are.

I also want to point out that our buildings and flood infrastructure were built 50 or even 100 years ago. They are aging, and they鈥檙e also not designed for the kind of severe weather we鈥檙e seeing now.

Flood mitigation is a very complex problem that needs collective effort from research communities, government agencies and industry.

Are drier places like Colorado at risk of floods?

Floods can happen anywhere, especially as climate change drives more weather extremes. Colorado has a drier climate, but it can still get very heavy thunderstorms. Because of the state鈥檚 mountainous terrain, it鈥檚 easy for water to rush down hillsides and trigger flash flooding.

And we have seen that happen. In 2013, heavy rains inundated Boulder and many towns along the Front Range, killing nine people and destroying nearly 2,000 homes.

What else can we do in addition to deploying better flood models?

Improving flood risk communication with the public is very important. Instead of just telling people there will be, say one meter or three feet per second of water flow in their area, we want to translate that into how much damage specific buildings might sustain and what actions people should take.

We鈥檙e also exploring customized alert systems. For example, we could provide tailored warnings for people with disabilities, parents with young children or others with specific needs. Current alerts are issued at the county level, but with better prediction tools, we could tell people exactly who鈥檚 at risk, where to go and when to leave.

Will federal funding cuts impact our ability to predict future disasters?

Budget cuts are certainly not helpful, but I also see it as an opportunity for industry and the research communities to step up.

I鈥檓 very optimistic about the future. I鈥檝e seen firsthand how much the technology has improved in just the past few years. I believe we鈥檒l soon have better warning systems, better flood models, and fewer lives lost to natural disasters.

探花视频 flood modeler Zhi Li explains why current flood warnings can leave communities unprepared鈥攁nd how high-resolution forecasting and better risk communication could save lives.

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Flooding of the Guadalupe River near Kerrville, Texas in 2025. (Credit: USCG/Wikimedia)

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Flooding of the Guadalupe River near Kerrville, Texas in 2025. (Credit: USCG/Wikimedia)

Electricity, air and plastic recycling

Megan Maneval — Thu, 26 Jun 2025 14:42:20 +0000

Electricity, air and plastic recycling Megan Maneval Thu, 06/26/2025 - 08:42

A collaboration between four fellows in the Renewable and Sustainable Energy Institute shows how electricity can be used to impart "superoxide powers" to oxygen gas molecules from air, enabling the efficient recycling of PET plastics.

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Wildfires threaten water quality for years after they burn

Megan Maneval — Tue, 24 Jun 2025 18:01:53 +0000

Wildfires threaten water quality for years after they burn Megan Maneval Tue, 06/24/2025 - 12:01

CIRES

CIRES-led research used big data to analyze more than 500 river basins鈥攂urned and unburned鈥攖o create and analyze the first large-scale dataset of post-fire water quality.

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Beneath crumbling walls: How rock glaciers took over the southern Rockies

Megan Maneval — Tue, 24 Jun 2025 15:54:18 +0000

Beneath crumbling walls: How rock glaciers took over the southern Rockies Megan Maneval Tue, 06/24/2025 - 09:54

INSTAAR

Rock glaciers are everywhere鈥攁t least in the Colorado Rockies. New research from Robert and Suzanne Anderson investigates how they formed and what benefits they might provide for alpine ecosystems.

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Mortenson Center innovations delivering clean water to more than 5 million worldwide

Megan Maneval — Mon, 23 Jun 2025 18:36:04 +0000

Mortenson Center innovations delivering clean water to more than 5 million worldwide Megan Maneval Mon, 06/23/2025 - 12:36

College of Engineering and Applied Science

探花视频's Mortenson Center in Global Engineering & Resilience is building a new model for global water access, one that is grounded in a deep understanding of why so many past efforts have fallen short.

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Farm-diversification research wins top international prize

Megan Maneval — Wed, 18 Jun 2025 19:11:14 +0000

Farm-diversification research wins top international prize Megan Maneval Wed, 06/18/2025 - 13:11

Colorado Arts and Sciences Magazine

探花视频鈥檚 Zia Mehrabi is one of three researchers named international champions of the Frontiers Planet Prize for research that finds environmental and social benefits of agricultural diversification.

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Climate & Environment

Report paints grim picture of how nuclear war could impact oceans

What happens when a nuclear weapon is detonated?

What would happen to the ocean, specifically?

Would people living far from coastal zones be impacted?

How long would it take for the ocean to recover?

Related Articles

Where does your food come from? First-of-a-kind map tracks journey across thousands of miles

Food hubs

Choke points

Related Articles

CUriosity: In the wake of Texas floods, how do emergency alerts work, and where do they fall short?

Related Articles

Waleed Abdalati to testify July 16 at congressional hearing

Watch the livestream here

Related Articles

Why flood prediction in the US falls short and how researchers are working to fix it

How does the official current flood prediction system work?

Where does this system fall short?

Is there a better way to predict floods?

Can we prevent damage from these increasingly common, record-breaking weather events?

Are drier places like Colorado at risk of floods?

What else can we do in addition to deploying better flood models?

Will federal funding cuts impact our ability to predict future disasters?

Related Articles

Electricity, air and plastic recycling

Related Articles

Wildfires threaten water quality for years after they burn

Related Articles

Beneath crumbling walls: How rock glaciers took over the southern Rockies

Related Articles

Mortenson Center innovations delivering clean water to more than 5 million worldwide

Related Articles

Farm-diversification research wins top international prize

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