From Watts Up With That?

By Charles Rotter

In recent days, climate skeptics have found support for their doubts about the so-called climate crisis. A recent study, The 2023 Global Warming Spike Was Driven by the El Niño–Southern Oscillation (Raghuraman et al., 2024), attributed the significant temperature spike in 2023 to natural causes, particularly the El Niño–Southern Oscillation (ENSO), rather than to anthropogenic factors. This seems like good news for those of us who have long been critical of the mainstream climate narrative. However, it’s important to remember that skepticism isn’t simply about accepting findings that align with our beliefs. Real skepticism demands a critical approach to all claims, including those that might seem to bolster our position.

Before we dive into why, let’s break down the study’s findings and the reaction it has generated in the climate skeptic community.

The Study: What’s It Really Saying?

Abstract

Global-mean surface temperature rapidly increased 0.29 ± 0.04 K from 2022 to 2023. Such a large interannual global warming spike is not unprecedented in the observational record, with a previous instance occurring in 1976–1977. However, why such large global warming spikes occur is unknown, and the rapid global warming of 2023 has led to concerns that it could have been externally driven. Here we show that climate models that are subject only to internal variability can generate such spikes, but they are an uncommon occurrence (p = 1.6 % ± 0.1 %). However, when a prolonged La Niña immediately precedes an El Niño in the simulations, as occurred in nature in 1976–1977 and 2022–2023, such spikes become much more common (p = 10.3 % ± 0.4 %). Furthermore, we find that nearly all simulated spikes (p = 88.5 % ± 0.3 %) are associated with El Niño occurring that year. Thus, our results underscore the importance of the El Niño–Southern Oscillation in driving the occurrence of global warming spikes such as the one in 2023, without needing to invoke anthropogenic forcing, such as changes in atmospheric concentrations of greenhouse gases or aerosols, as an explanation.

https://acp.copernicus.org/articles/24/11275/2024/

The study conducted by Raghuraman et al. (2024) takes a deep dive into the sharp 0.29°C global surface temperature increase observed between 2022 and 2023. While alarming on the surface, the authors provide evidence that this spike, while significant, was driven primarily by natural variability—specifically the El Niño–Southern Oscillation (ENSO) cycle. They argue that this spike is consistent with previous instances of similar natural warming events, such as the one seen in 1976–1977, and that there is no need to invoke anthropogenic factors like greenhouse gases or aerosol reductions to explain the phenomenon​.

The key point here is that the study uses climate models to show that such large warming spikes are rare but possible through internal climate variability alone. In unforced climate model simulations, warming spikes of this magnitude happen only 1.6% of the time. However, when an El Niño event is preceded by a prolonged La Niña, the probability of a spike jumps to 10.3%. Nearly all spikes (88.5%) in the models occur during El Niño events, highlighting the strong link between this natural climate cycle and short-term global temperature changes​.

Interestingly, the authors also provide a probabilistic breakdown to support their case. They show that individual factors like La Niña or El Niño alone can raise the likelihood of a spike to about 6%, but the combination of a prolonged La Niña followed by El Niño increases the odds significantly. This underscores the power of natural variability in generating sharp year-on-year warming spikes, a point often underplayed in the climate debate​.

In addition to examining 2023, the study also looks at historical warming spikes, pointing to similar events like the 1976–1977 spike that coincided with a similar La Niña–El Niño transition. Despite this similarity, the study admits that drawing broad conclusions from just two historical examples is difficult, which is why they rely on multi-century climate simulations that span thousands of years to capture a wider range of variability​.

The authors conclude that the 2023 spike can be explained by internal variability alone, with ENSO playing the dominant role. This challenges alarmist views that immediately point to human-induced climate drivers.

This detailed probabilistic analysis adds nuance to the discussion, but it also highlights the reliance on climate models, which brings us back to a key issue for skeptics: how much trust should we place in these models, given their known limitations? Even though this study appears to support a skeptic’s viewpoint, the underlying tools remain the same—models that fail at long-term prediction. Therefore, while this study may provide some context for 2023, it should not be treated as definitive proof without critically assessing the assumptions and limitations of the models involved.

What’s the Problem? The Danger of Cherry-Picking Studies

It’s tempting to take this study and run with it. After all, it gives climate skeptics the opportunity to point to peer-reviewed research that aligns with our views. But this raises an uncomfortable question: should we trust a study just because it seems to confirm our beliefs? The short answer is no.

For years, many skeptics have expressed well-founded criticisms of climate models, the very tools used in this study. These models have a notorious history of overestimating future warming, and their predictions often diverge significantly from observed temperatures. Even the Intergovernmental Panel on Climate Change (IPCC) has had to admit to such discrepancies. So, if we reject climate models when they predict runaway warming, should we embrace them when they tell us something we like?

This is the heart of true skepticism. We cannot afford to pick and choose when to apply our critical thinking. The reality is, this study relies on the same type of climate models that many of us have questioned for years. These models may be adjusted to simulate internal variability better than they have in the past, but they remain subject to the same uncertainties and assumptions that have always plagued them.

The Role of Climate Models: Uncertainty Still Reigns

One major issue with climate models is that they are only as good as the data and understanding we have of the climate system. For example, the models used in this study may do a somewhat decent job simulating ENSO cycles, but they still struggle with long-term forecasts and complex feedback mechanisms, such as cloud formation and ocean circulation patterns, that are critical to understanding climate dynamics over decades or centuries. This is precisely why many skeptics argue that climate models should not be used to justify sweeping policy decisions like the Green New Deal or Net Zero initiatives.

In this case, the study’s authors acknowledge the uncertainty inherent in their model-based approach. They note that while the models can reproduce warming spikes similar to 2023, these events are relatively rare in the simulations. Furthermore, the simulations suggest that while ENSO was the primary driver of the spike, other internal variability factors could have played a role. This leaves room for doubt and should temper any overenthusiastic interpretations of the study​.

Don’t Forget the Models’ Long-Term Failings

Another important aspect of skepticism is context. Even if this study accurately captures the dynamics of the 2023 warming spike, that doesn’t change the fact that climate models, in general, have a poor track record when it comes to long-term predictions. For example, back in the 2000s, many models predicted a steady rise in global temperatures, yet we experienced a so-called “hiatus” from roughly 1998 to 2013 where warming slowed considerably. This discrepancy between model predictions and real-world observations was downplayed by climate alarmists, but it’s a clear indication that models are far from perfect.

In this case, the authors of the 2023 study may have tuned their models to better simulate short-term variability, but that doesn’t mean the same models will perform well when projecting future warming trends decades into the future. Given that these models have consistently overshot actual temperature increases in the past, it’s reasonable to remain cautious about their predictions.

Natural Variability vs. Anthropogenic Forcing

One of the key takeaways from this study is the reminder that natural variability—things like ENSO, volcanic activity, and solar cycles—plays a crucial role in driving short-term climate fluctuations. While climate alarmists love to emphasize the role of CO2 and other greenhouse gases, they often downplay the significance of these natural forces, especially when they contradict the catastrophic warming narrative. By highlighting the role of ENSO in the 2023 spike, this study serves as a useful counterpoint to the oversimplified narrative that all warming is caused by human activity.

However, it’s also important not to fall into the trap of assuming that natural variability is the only factor at play. The climate system is undoubtedly complex, and while studies like this one suggest that natural forces were behind the 2023 spike, they don’t completely rule out the role of some anthropogenic factors. The challenge is distinguishing between the two and determining their relative influence over different timescales.

The Pitfalls of Confirmation Bias

The most valuable lesson this study offers is a reminder about the dangers of confirmation bias. Just as climate alarmists often seize on studies that confirm their doomsday predictions, skeptics can be guilty of the same behavior when presented with research that supports their views. But true skepticism is about maintaining a critical mindset regardless of whether the findings agree with our preconceptions.

If we are to remain intellectually honest, we must apply the same level of scrutiny to this study as we would to any research that claims catastrophic warming is imminent. This means recognizing the limitations of the climate models used, questioning the assumptions behind the simulations, and acknowledging the uncertainties in the results. It also means being open to the possibility that natural variability and anthropogenic factors can both influence global temperatures in ways that are difficult to disentangle.

Conclusion: Stay Skeptical, Even When It’s Tempting Not To

In conclusion, while the 2023 global warming spike study offers an intriguing explanation for the recent temperature increase, it should not be treated as definitive proof that natural forces alone are responsible for all climate change. Instead, it serves as a reminder of the complexity of the climate system and the limitations of our current models and understanding.

As skeptics, we should resist the temptation to embrace this study simply because it seems to support our views. Instead, we should remain cautious, critically evaluate the findings, and recognize that the same uncertainties and limitations that apply when criticizing alarmist models also apply here. Skepticism isn’t about being contrarian for the sake of it; it’s about applying a consistent, rigorous standard of inquiry to all claims, no matter which side of the debate they fall on.

This study reinforces one important truth: natural variability plays a significant role in the climate system, and we should be wary of any narrative that claims human influence is the sole driver of climate change. But in the end, the models used in this study are still just that—models. And as history has shown, they can often get it wrong. So let’s continue to demand better evidence and avoid jumping to conclusions, even when the data seems to be on our side.