In this insightful discussion, David Helvarg and Vicki Nichols Goldstein engage with Daniel Swain, a prominent weather and climate scientist. They explore the complexities of El Niño and its unpredictability, shedding light on the broader implications of ocean temperatures on climate patterns.
By David Helvarg and Vicki Nichols Goldstein. Helvarg is an author and the executive director of Blue Frontier, an ocean policy organization, and co-host of the Rising Tide Ocean Podcast. Nichols Goldstein is the founder and director of the Inland Ocean Coalition. Originally published at Common Dreams.
On August 22, the ocean surface temperature reached an unprecedented high of nearly 70°F. As ocean temperatures rise, I and Vicki Nichols Goldstein of the Inland Ocean Coalition spoke with Daniel Swain, a scientist at the University of California’s California Institute for Water Resources and the National Science Foundation’s National Center for Atmospheric Research, during our Rising Tide Ocean Podcast. Here’s a summary of that conversation:
David Helvarg: Before we delve into the rapidly warming ocean and its repercussions, could you provide some context?
Daniel Swain: I’ve always had a strong interest in weather, even as a child. Pursuing an atmospheric science degree at UC Davis, I initially aimed to become a federal meteorologist with the National Weather Service. However, I soon recognized that some of the most intriguing and important questions arise at the intersection of weather and climate. While we can accurately forecast the weather, the changing climate introduces uncertainties. What implications does this have for weather patterns?
My background is rooted in daily weather and forecasting. Today, I consider myself a climate scientist existing at the blurry boundary between weather and climate—a distinction that becomes increasingly hard to define. Both the ocean and atmosphere are interconnected fluids, each influencing the other.
I often describe the ocean as “the atmosphere turned upside down and saturated with water.” This perspective highlights that the atmosphere, ocean, biosphere, and cryosphere (frozen water) are not distinct systems. As we attempt to model Earth systems, it becomes clear that to accurately predict weather, we must also account for oceanic influences, and vice versa.
Helvarg: Let’s consider the ocean on a larger scale. Many people may not realize the ocean’s role in driving climate and weather, despite it comprising over 70% of our planet.
Swain: Right. We inhabit a water planet, even if we often overlook this fact. Since over 70% of Earth is ocean, long-term atmospheric fluctuations are primarily influenced by oceanic conditions. Climate change, fundamentally, is a manifestation of ocean warming, as most of the excess heat is absorbed by the seas. This stored heat subsequently impacts the atmosphere, contributing to various terrestrial consequences.
One way to understand global warming is as an accumulation of energy in the oceans that then spills over to the remaining third of the Earth not covered by water.
Vicki Nichols Goldstein: It’s known that approximately 90% of excess heat is retained in the ocean. What enables the ocean to absorb so much more heat compared to land?
Swain: Primarily, the ocean occupies most of the planet’s surface. Warming the entire sphere means that the ocean, as the dominant feature, absorbs most of that energy. Additionally, water possesses a high specific heat capacity, which allows it to absorb substantial energy compared to an equivalent mass of land. This absorption occurs over vast depths.
Whereas geological processes on land unfold over millions of years, changes in the ocean can occur much more swiftly. An individual water molecule can travel from the ocean surface to the atmosphere and then descend thousands of feet into the deep ocean within just a few years. The ocean effectively transfers energy from the surface to its deep layers.
Unlike the atmosphere, which can change rapidly—like a cumulus cloud rising 20,000 feet during a thunderstorm in just 20 minutes—the ocean’s movements are slower but can still occur over days, months, or years. In contrast, land processes can take millions of years, which is why the ocean and atmosphere are tightly coupled and interact continuously.
Helvarg: People also struggle to grasp the speed at which these changes have occurred. Since we began burning fossil fuels a few centuries ago, we have significantly altered the ocean’s physical characteristics—its temperature, chemistry, circulation, and even its color. What do rising ocean temperatures signify for marine heatwaves?
Swain: Marine heatwaves refer to unusually warm ocean temperatures, primarily at the surface, which are our most easily observable indicators. These heatwaves have become more frequent, intense, and connected spatially each year and decade, with no signs of slowing down.
As long as global warming continues, marine heatwaves are expected to accelerate. Additionally, marine heatwaves can persist longer because water has greater thermal inertia than air. A significant blob of warm water can’t simply be dispersed by strong winds, like a land heatwave. Instead, that ocean temperature anomaly can linger for weeks or even months.
Interestingly, this persistence is also why the ocean plays a crucial role in atmospheric predictions. The ocean changes more slowly, storing “memory” that influences atmospheric conditions. Essentially, as the air warms, the ocean beneath it will warm too, albeit unevenly due to currents and atmospheric dynamics.
Goldstein: There’s a lot of talk about La Niña and El Niño. What occurs during this transition?
Swain: El Niño and La Niña are part of a broader pattern of natural ocean variability known as the El Niño-Southern Oscillation (ENSO). El Niño represents the warm phase, while La Niña signifies the cool phase. It essentially refers to whether the eastern tropical Pacific, particularly near Peru and South America, is warmer or cooler than average, a region typically characterized by cold water upwelling.
During El Niño, the upwelling of cold water weakens as warm water from the western Pacific flows eastward. The easterly winds driving upwelling may also weaken or reverse. This significant warming in the eastern tropical Pacific defines the El Niño phenomenon.
Globally, this matters because ENSO acts like a thermostat for the climate system. Heat accumulates below the surface during La Niña, while El Niño releases stored energy from the ocean into the atmosphere, distributing it throughout the climate system.
Swain: When El Niño releases stored energy from the tropical ocean, it raises the global average temperature. In a warming world, introducing an El Niño event amplifies the likelihood of record-breaking temperatures. It also speeds up the hydrologic cycle.
The capacity of warmer air to hold more water vapor results in greater extremes in precipitation patterns. While some regions may experience increased flood risks during El Niño events, others could face heightened drought or wildfire risks. El Niño shifts weather patterns while global warming exacerbates the extremes they produce.
Helvarg: On the West Coast, my interactions with El Niño often mean increased storm events. How significant is this correlation?
Swain: El Niño does have a noticeable impact on California’s weather, though it’s sometimes challenging to quantify due to the many factors at play. Nevertheless, during a particularly strong El Niño, the consequences become more pronounced.
I’ve consistently communicated to emergency management and policy circles that recent El Niño events haven’t always yielded the expected outcomes. For instance, the 2015-16 El Niño was one of the strongest recorded, yet California did not experience the anticipated strong effects. Some might interpret that as a sign of El Niño’s diminishing relevance; however, its strength is crucial. A significant El Niño can distinctly influence local sea levels, elevate California’s nearshore ocean temperatures, raise flooding risks, and increase the chances of a wetter-than-average winter.
In fact, if asked for a singular global climate predictor that might provide three to six months’ notice of a potential very wet winter in California, I would point to a strong El Niño.
Goldstein: What does this mean for California’s mountain snowpack and the broader western U.S.?
Swain: This aspect complicates matters, as varying temperatures influence precipitation differently in a warming world. A winter may not be particularly dry but still yield low snowpack due to warmth. In some cases, below-average snowpack can occur even with above-average precipitation. Thus, while a strong El Niño could boost precipitation in California and the Sierra Nevada—as well as in parts of the Colorado River Basin—more precipitation does not guarantee more snow (especially if it falls as rain). This might alleviate drought conditions, but it creates a starkly different scenario than a cold, snowy winter.
Helvarg: Looking towards the Atlantic: It’s suggested that strong El Niño events suppress Atlantic hurricanes. Is that correct, and why?
Swain: Yes, that’s a valid point. El Niño generally reduces Atlantic hurricane activity primarily due to its influence on vertical wind shear, rather than temperature. Hurricanes struggle to form amid strong upper-level winds, which can disrupt their structure. El Niño tends to increase wind shear in the regions conducive to hurricane development, complicating the formation of such storms.
However, there’s a caveat: if sea surface temperatures are exceptionally high, such as in the Gulf of Mexico, a storm can still become extremely powerful even if it develops during an El Niño phase. This illustrates how natural variability, like ENSO, interacts with ongoing climate warming to create outcomes that are increasingly difficult to predict.
Goldstein: This leads us to the issue of climate science. Changes within the Trump administration regarding Office of Management and Budget regulations could influence federal research funding based on presidential agendas. What are the implications for climate research and communication?
Swain: This extends beyond just weather and climate; it can affect any area that relies on expert knowledge for critical decision-making—from public health to policy formulation to research support. Recent shifts in research funding have raised concerns, but it’s vital to understand their broader implications.
Many in academia and research are alarmed by these developments. Political influence over the federal grant system could hinder our ability to comprehend the world and respond to future crises, whether they involve storms, flooding, pandemics, or geopolitical unrest. It will become increasingly challenging for scientists to maintain impartiality and focus solely on their studies.
If funding hinges on research topics aligning with current political priorities, this fundamentally alters scientific inquiry—an extremely concerning trajectory.
Goldstein: This underlines the need for public engagement in these matters, advocating for transparency and accountability.
Helvarg: Democracy alone doesn’t guarantee effective ocean stewardship or science-based public policy. Nonetheless, without it, addressing existential issues like climate change and ocean protection becomes immensely more difficult.
