Chapter 1: The Climate versus Weather Distinction

I reside in Boulder, Colorado, a picturesque location that offers various outdoor activities in the mountains. Recently, we experienced an unusual warm spell, with temperatures frequently reaching the 50s (Fahrenheit) during January, which is quite atypical. This unexpected warmth stirred some anxiety about climate change within me. While it’s true that human activities continue to elevate carbon dioxide levels in the atmosphere, leading to a general rise in temperatures, I realized I was making a critical mistake in my reasoning.

The separation between weather and climate is crucial. An isolated warm spell cannot be used to assert that the climate is warming. Instead, one must examine the long-term trends to draw any conclusions about climate. The warm weather I encountered is merely a case of weather, so it cannot be used as proof of climate change. However, an increase in the frequency of unusually warm days over the years would indicate a shift in climate.

Below, you can see a graphical representation of global temperature changes over the years. Each dot corresponds to the global temperature for a given year, normalized to an average temperature of zero on the y-axis. For instance, in 2000, the air temperature was approximately 0.4 degrees Celsius above the average. While there are fluctuations, the overarching warming trend is evident. Later, I will discuss some reasons for these fluctuations.

(Source: NASA)

Both sides of the spectrum must be considered; just as one cannot claim climate change is disproved by an unusually cold week in summer, studying climate requires data over a sufficiently long period. Most climate scientists agree that a minimum of 30 years' worth of data is necessary to make credible claims about climate. The chart above can be viewed as a series of snapshots of an evolving climate, extending well beyond the three-decade mark.

Chapter 2: The Importance of Context in Climate Data

In the video "Making Weather and Climate Data Work for You," the importance of understanding climate data is explored, illustrating how to interpret data effectively.

In a notable misrepresentation of climate and weather, U.S. Senator Jim Inhofe famously used a snowball during winter as an argument against global warming. (Source)

All climate-related data must be contextualized appropriately. Most of this information involves comparing current data with historical values. While the previous example illustrates the difference between weather and climate, there are several other critical distinctions in climate science. In this discussion, I will present three additional examples to emphasize the importance of context.

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Section 2.1: The Oceanic Offset

Climate change skeptics frequently manipulate data context to mislead the public. This tactic is particularly detrimental, fostering a misconception that the science remains unsettled, despite over 97% of published studies agreeing on human-induced climate change. Education remains the most effective tool against such misleading information. Let’s examine a common tactic used to mislead and the scientific evidence that counters it.

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The image above has been used to claim that climate change is not occurring. While the data itself is genuine (as seen in the earlier graph), it has been presented selectively. First, only 14 years of data are shown, which is insufficient to draw any conclusions about climate. Furthermore, the year 1998 was chosen as the starting point, a year marked by a significant climate event that creates an impression of stable or cooling global temperatures.

The Pacific Ocean experiences major fluctuations known as the El Niño Southern Oscillation (ENSO), which manifests as either warming (El Niño) or cooling (La Niña) events. These phenomena influence global temperatures and cycle every 2 to 7 years, potentially altering global temperatures by as much as 0.3 degrees Celsius. Given their significance, climate scientists invest considerable effort into predicting these events.

This plot illustrates the ENSO index over time. Note that the y-axis is a specific value designed to remain flat for consistency and does not represent global temperatures. The red periods indicate El Niño events, leading to a rise in global temperatures, while the blue periods reflect La Niña events, resulting in cooling. This time series appears chaotic but follows a general cyclic pattern. The dramatic fluctuations around 1997/1998 coincide with the most significant El Niño event recorded, explaining the perceived global cooling when viewed in isolation.

Many fluctuations in our global temperature plot align with these insights, such as the cool period around 1955, which corresponds with a strong La Niña event, and the pronounced warming during the notable 2015/2016 El Niño.

When analyzing global temperature data, it is essential to consider the time frame presented. A specific starting year may be chosen to mislead observers into thinking the planet is not warming. Be cautious if the selected starting years are 1982, 1998, or 2015, as these are often used to suggest a lack of warming. Likewise, starting plots in 1973, 1989, or 2000 may exaggerate the perceived warming trend.

Given the abundance of temperature data available, one should always question the motives behind selective data presentation.

Section 2.2: Historical Climate Context

Our planet has undergone significant climate changes throughout history, far exceeding the 30-year intervals typically used in modern studies. Over the past million years, Earth has cycled through ice ages, experiencing temperature variations of roughly 5 degrees Celsius, with carbon dioxide levels fluctuating by around 90 ppm.

Climate change skeptics often reference this historical context to downplay humanity's impact on current climate changes. However, such claims can be easily debunked. As the theme of this article suggests, we must contextualize both natural and human-induced changes to understand their implications.

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The graph above depicts atmospheric carbon dioxide levels over the past 800,000 years, derived from extensive research, primarily using ice core data. Scientists extract air bubbles trapped in ancient snow layers from Greenland and Antarctica to measure historical carbon dioxide concentrations. This research is further supported by diverse data sources, including fossils, tree rings, and geological records.

While it is evident that carbon dioxide levels have varied over time, the most recent changes are unprecedented in both speed and scale. Notably, we were already in a period of elevated carbon dioxide levels at the onset of the Industrial Revolution, making recent alterations even more striking. Clearly, we are witnessing a different phenomenon.

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The past fluctuations in carbon dioxide levels have generally been attributed to Milankovitch Cycles, which occur over tens of thousands to hundreds of thousands of years. Extensive literature connects these cycles to ice ages. My doctoral research focuses on this topic, examining how Milankovitch Cycles influence ocean dynamics in climate models, correlating findings with existing data.

The key takeaway is that while Milankovitch Cycles are gradual, human-induced emissions from fossil fuels are rapid. The most rapid increase in carbon dioxide levels, as shown in the graph, is unprecedented and indicative of anthropogenic influences.

Chapter 3: The Fast Pace of Current Climate Change

In the video "VT2.4 Visualizing Climate Data in Excel," viewers learn how to effectively visualize and analyze climate data to better understand its implications.

Another argument often made by climate change skeptics refers to a period approximately 56 million years ago when Earth was about 7 degrees Celsius warmer than it is today, known as the Paleocene-Eocene Thermal Maximum (PETM). Detractors of climate change often cite this as evidence against current human-induced climate change. I have encountered such claims in previous discussions.

However, the timescale is crucial in this context. Estimates suggest that it took roughly 10,000 years to reach the warming levels observed during the PETM. While this rate of change is significant, it pales in comparison to the current trajectory, which recent studies estimate could reach similar temperatures in about 150 years if we continue on our current path without transitioning to renewable energy.

When comparing past events, it is vital to consider the speed of change. Rapid alterations in the planet’s climate pose challenges for ecosystems to adapt and evolve.

These examples underscore the importance of context in understanding climate data. Timing is everything!

Going Further

I hope this discussion has provided valuable insights! Properly contextualizing climate data is essential for accurate understanding. An informed public capable of critically analyzing presented data will be better equipped to navigate pressing issues. For further exploration, I’ve included several resources:

• The Wikipedia page on climate change denial offers interesting discussions and a solid starting point to understand the strategies employed in this discourse.
• The IPCC report serves as an excellent resource for the latest consensus on climate change. While lengthy, summaries are available on their website.
• CarbonBrief features up-to-date news regarding climate change and current efforts to address it.
• Amidst overwhelming negative narratives about climate change, it’s crucial to seek out positive stories, such as advancements in climate solutions.
• The PETM represents a compelling event in Earth's history; you can read more about it on this page.

Additionally, you might find interest in similar articles I’ve written. Consider following me for more insights on science and mathematics!