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As we enter this summer’s highly anticipated Super El Niño, which is expected to drive several extreme heat records around the world, I look back to the extreme heat coverage during our most recent El Niño event in 2023. When I do, I see a concerning recurring framing, sometimes from very reputable and well-intentioned outlets. Scientists are shocked and astonished. Climate change is out of control.
A similar thing happened last month with a different story. After a new scientific paper advanced a climate modeling framework that replaced an old extreme climate scenario with a less severe one, President Donald Trump posted to social media that climate scientists had admitted to being “WRONG! WRONG! WRONG!” Headlines didn’t dispute this falsehood, saying scientists retired their old model, backtracked, reversed course, and now say something different.
Sure, it makes good drama. But it also implies climate scientists got something wrong. In these two cases and most others, they didn’t.
Earlier this month, I published two op-eds on what may be two sides of the same coin. On June 2, I wrote in Common Dreams on how we averted a worst-case scenario for climate change through a decade of massive clean energy deployment, which is why scientists have narrowed their range of plausible climate outcomes. On June 3, I wrote in SEJournal on how this summer could see several disastrous extreme heat records around the world and make 2026 cross the 1.5 degree warming threshold that the world committed to stay under in the Paris Agreement.
In the former piece, we rule out a worst-case scenario. In the latter, we rule out a best-case scenario. Yet when reporters cover either topic, they seem to fall into the same trap: they treat updates as a sign that scientists are confused and backtracking, rather than as an intentional process scientists use to be honest and accurate.
Climate science is not intended to be a set of perfect predictions waiting to be proven right or wrong. It is an ongoing process of narrowing possibilities, testing explanations, assessing risks, and updating what we know as facts on the ground change. When journalism flattens that process into “scientists were wrong before” or “scientists are shocked now,” it does more than just misinform. It makes science look less reliable at precisely the moment when scientists are being most trustworthy and transparent.
Uncertainty 101
To journalists, and likely most people, the word “uncertainty” is usually associated with not knowing something. But when scientists use the word uncertainty, that’s actually not what they mean.
In science, uncertainty does not mean knowing or not knowing, but rather how well something is known. It is the difference between saying “we have no idea what will happen” and saying “based on the evidence we have, this outcome falls within this range of possibilities, with this level of confidence.” That distinction matters enormously. The first is ignorance. The second is precision.
Though it may feel counterintuitive, uncertainty is a feature of science, not a bug. Most scientific findings or forecasts are presented as a range of possibilities, often with a level of confidence that signals the likelihood the true result lies inside the given range. Scientists use ranges, error bars, assumptions, caveats, and confidence levels not because they are trying to wriggle out of being wrong, but because they are trying to communicate what a finding can and cannot assert. This process is what allows science to be transparent and trustworthy, to the point where when scientists emphatically and collectively say that they do know something, we know that they’ve done more than their due diligence.
This concept of scientific uncertainty is especially relevant in climate and environmental science. Climate change is not unfolding in a laboratory with one variable and one outcome. Scientists know that pumping more greenhouse gases into the atmosphere will warm the planet. They know that human-caused climate change is the predominant force exacerbating extreme heat and many other events. But they cannot know in advance exactly how much humans will emit, how quickly technologies and policies will change, how strongly different climate feedbacks will amplify or dampen warming, or how natural variability like El Niño will layer on top of the long-term warming trend. So instead of pretending the future can be reduced to a single prediction, scientists use many tools that reflect complexity and deliver the most precise answers they can obtain with the information they have.
Journalists are also trying to describe reality, but journalists are often trained to push in the opposite direction. Reporters work on tight deadlines and short word counts, which can make grasping the uncertainties in a scientific research paper challenging. Editors even less steeped in the research may favor headlines that are clear, definitive, eye-popping, and emotionally charged. News stories often favor hard facts, dramatic contrasts, and snappy quotes from authorities. In that environment, scientific uncertainty can feel to journalists like a foreign concept, or even a nuisance, rather than a key part of the story to explain. Why won’t this scientist give me a straight answer?! I need a good soundbite!
But readers can handle nuance. In fact, they need it. Communities will be best equipped to understand risk, ask questions, and respond to a changing world if they understand the full picture: what scientists know, what they are still measuring, what is driven by human-caused climate change, what is shaped by natural variability, and how human choices can still change the range of possible outcomes. Without that context, climate communicators can quickly sow doubt in the very science they intend to share.
Too hot
As I wrote in SEJournal, this summer’s El Niño could be record-shattering. If that proves true, we are likely to see plenty of daily temperature records, new extreme weather events, and the strong possibility that the world temporarily surpasses 1.5 degrees Celsius of warming from preindustrial times.
That presents a critical climate communication test. Some reporters may be tempted to describe every record as evidence that climate change is spiraling out of control, as many 2023 articles did. Others unfortunately may resist making links to climate change at all. Neither instinct properly explains the science or serves communities trying to understand what is happening.
El Niño is part of a natural climate pattern called ENSO in the tropical Pacific. During its counterpart, La Niña, stronger trade winds push warm surface water westward and allow colder water to rise in the eastern Pacific, slightly cooling global temperatures. And during El Niño, those trade winds weaken, leaving more warm surface water in the eastern Pacific and allowing more heat to radiate into the atmosphere. The result then is a temporary boost to global temperatures layered on top of human-caused climate change, driving more extreme heat and shifting patterns for droughts, floods, hurricanes, and more. Scientists have suggested climate change could be correlated with more extreme ENSO cycles, but generally, ENSO is considered a natural phenomenon.
That layering is the key. Human-caused climate change is by far the primary driver of a given heat record. Often, scientists find a given temperature would be virtually impossible without human-caused climate change. But it is El Niño providing the nudge to turn many hot days into record-breakers.
Communicating one force without the other provides incomplete information. Only spotlighting climate change sends the message that it is the sole driver of record-breaking weather, which can leave audiences confused or skeptical during La Niña events when such records suddenly seldom occur. And excluding climate change’s role leaves people in the dark about the primary factor that is worsening these extreme events.
This is where uncertainty is easy to mishandle. The uncertainty is not over whether human-caused climate change is warming the planet or worsening extreme heat. It is. The uncertainty is in exactly how this year’s natural variability will interact with that long-term warming trend: which records will fall, how far outside expectations they will land, and how best to understand one extreme year within the context of a larger timeline.
We have seen the damage imprecise framing can do. In 2012, three years into an extreme La Niña event, climate deniers capitalized on the finding that temperatures that year matched the global average from 1998, a severe El Niño year. Several news outlets and politicians spread the falsehood that the world was in a “global warming hiatus,” having seen no warming in fourteen years! After drafts of the 2013 IPCC report that hadn’t yet nailed down language to explain the natural variability were leaked, some mainstream reporters further mischaracterized the story by claiming that even the scientists were perplexed.
Just as climate deniers were wrong to claim an extreme La Niña was evidence of a global warming pause, climate-concerned communicators would be wrong to claim an extreme El Niño is climate change inexplicably spiraling out of control for a year or two.
The same care applies to the 1.5 degree threshold. The latest El Niño, in 2023-24, was long and hot enough to make 2024 the first calendar year to exceed 1.5 degrees Celsius of warming above preindustrial levels. With the Paris Agreement establishing a goal of keeping global warming below 1.5 degrees by 2100, and scientists noting the possibility of reaching some climate tipping points at 1.5 degrees, crossing that threshold in a given year lends itself to plenty of apocalyptic headlines full of “shocked” and “alarmed” scientists.
But like daily records during El Niños, annual records should be communicated with care. For one, the Paris Agreement is not a pass-fail exam. The 1.5 degree target refers to the long-term trend line, not a blip in a given year. Even if the trend line crosses 1.5 degrees, there remains the possibility of a carbon-negative world where temperatures bend back down under the threshold by the end of the century. And most importantly, though the target isn’t entirely arbitrary, every tenth-of-a-degree of global warming averted saves lives, defends critical ecosystems, and reduces loss and damage. For those familiar with scientific uncertainty, a spike over 1.5 degrees looks very different from a trendline crossing it, and even a trendline crossing it can mean many things. But excluding that context can make even the blip sound like game over. If the public believes that “we failed” on climate change or that it is “running amok” — especially due to one data point inflated by El Niño — they lose all reason to keep engaging.
That is why understanding uncertainty matters so much, particularly this summer. The certain part is that human-caused climate change is worsening extreme heat, and El Niño can temporarily amplify that heat. The uncertain part is exactly how those forces will interact this summer: which records will fall, how far outside expectations they will land, and how this one hot year should be understood within the larger trend. None of that means scientists are confused. It means they are separating what is known from what is still variable, including the elements shaped by future human decisions, and being precise and transparent in their communication.
Too cold
My piece in Common Dreams offers the opposite version of the same problem. In the El Niño example, the danger is that an unusually hot year can make climate change look like it is suddenly exceeding scientists’ understanding. In this case, the danger is that when humans avert a worst-case scenario, it can make climate change look like it was exaggerated all along.
Climate models are not predictions. They are tools to understand how the climate would respond to different human actions, from rapid emissions cuts to current policies to backsliding into more fossil fuels. As such, scientists do not create one model, but many models called scenarios or pathways, with each one studying something different. Each of these scenarios is always depicted as a range, where scientists select a particular human choice (i.e. current policies), determine the level of emissions that would generate, and show a range of possibilities for how temperatures might change as a result. The further into the future a scenario is modeled, the wider the range will be. Scientists do not claim that the future is guaranteed within that range; rather, they place a level of confidence on it. In simple terms, they may say “if humans take these specific actions, there is a 95% chance that the climate warms between x degrees and y degrees.” This is not guesswork, but a very deliberate statistical process to identify exactly where that range lies. The more data scientists collect, the more narrow those ranges can become.
The most extreme of these widely used climate scenarios, called RCP8.5, studied a world with no climate policy and exceptionally high fossil fuel use through the rest of the century. Though always meant as an unlikely outlier, RCP8.5 has become far less plausible after a decade of accelerated clean energy deployment, to the point that the aforementioned new paper proposed replacing it in future research. That should have been a climate win: Humans avoided the worst pathway and scientists revised models accordingly. Yet many outlets, including mainstream ones, managed to frame this as scientific failure, suggesting that scientists got it wrong, not that they simply updated the scenarios they study to account for climate progress.
This is the human agency piece of scientific uncertainty. When the Paris Agreement was signed in 2015, the world was projected to warm by nearly 4 degrees Celsius, not much better than the RCP8.5 nightmare scenario. Today, based only on current policies, that projection is down to 2.6 degrees Celsius. That trajectory is, of course, a ways away from the 1.5 degree threshold I discussed earlier. A 2.6 degree world would still be incredibly costly, unjust, and catastrophic. But these improvements are substantial, drastically reducing the risk of reaching several tipping points this century including East Antarctic glacier collapse, northern permafrost collapse, and a West African monsoon shift. Given how unlikely it would be for the entire world to completely reverse course, shut down all their solar and wind farms, and go on a far more expensive coal and oil frenzy, it no longer made sense for scientists to keep RCP8.5 on the list of plausible pathways.
If climate science were a single prediction, then moving away from that prediction could look like failure. But because climate science works with ranges, assumptions, and pathways, it can show when the range of plausible futures has narrowed for good reasons. It is precisely why uncertainty is such a valuable part of the scientific method. The certain part is that more greenhouse gas emissions will cause more warming, all of these pathways are dangerous, and lowering emissions does on average promote less catastrophic outcomes. The uncertain part is exactly how much humans will emit; how strongly clouds, water vapor, surface reflectivity, and other feedbacks will amplify or dampen additional warming; or how oceans, forests, permafrost, and other natural systems will absorb or release carbon as the planet changes. That uncertainty is not only good science, but a reminder that we as humans have agency in our climate future.
Just right
Next week at Metcalf Institute, we will be welcoming ten journalists to campus for our weeklong Annual Science Immersion Workshop, where we’ll take journalists into labs and into the field to actually do science and interact with scientists. I love that in both this role and my previous one hosting The Sweaty Penguin, I have had so many opportunities to interact with scientists and learn how they think about the world.
Uncertainty is truly at the core of their work. Scientists are extremely precise in how they communicate their research, and always more interested in discussing what they don’t know than what they do know. It is, after all, why they have jobs. I have always found their tools for understanding uncertainty to be one of the key reasons why I find science so trustworthy and valuable.
It is also so different from how journalists operate, and is so often where scientists and journalists misunderstand each other. And it is so often the scientists that get blamed or distrusted by the public when journalists, often with the best intentions, miscommunicate the absoluteness of their findings. If I’m counting right, Tuesday will be my fifth time facilitating a workshop for journalists on scientific uncertainty. I have long considered this workshop one of my favorites to lead, and look forward to the insights we come up with.
Until we at Metcalf can train every newsroom in the world, however, it is very likely that between this summer’s possible heat records and the fallout of last month’s climate modeling debacle, many headlines will miss the mark on uncertainty. When they do, my advice is to go deeper than the headline, and be skeptical if a headline implies scientists are wrong, shocked, or any more alarmed than they already have been. If a story suggests scientists are wrong, see whether they genuinely made a methodological error and received criticism from peers, or if they were simply updating data or following their process. If a story suggests scientists are surprised, see if that’s actually true, and if so, whether it is because an outcome was at the edge of their error bars or outside them, remembering that neither of those situations automatically means the scientists got something wrong (though occasionally it does). If a story suggests climate change is out of control, ask whether it is overreacting to an El Niño outlier or if scientists genuinely identify a tipping point such as permafrost collapsing or a massive coral bleaching event. And remember, as bad as it gets, there is no scenario where we “failed” climate change. Climate solutions around the world are scaling fast, and though it needs to be faster, every bit still helps.
This summer may bring some brutal weather, and with it, some frightening climate stories. But new weather records shouldn’t be accompanied by insinuations that scientists were caught flat footed. Whether scientists are forecasting temperatures on a summer day or developing a range of complex models for the future climate, the uncertainty inherent to that process is not a drawback. Often, it is the very thing that helps us understand what we know is happening, what could happen moving forward, and how our continued climate action can still avert disasters in the future.