Modern climate narratives often emphasize recent warming driven by CO2, but historical data reveals a more nuanced story where natural variability and human-driven factors like CO2 work together as complementary forces. While CO2 undoubtedly influences modern climate, research continues to unravel its role alongside natural variability—a complexity this article explores through historical climate patterns. Temperature records from Reykjavik, Iceland (1900-2017), Arctic warming reports from the 1920s, El Niño impacts in South America in the 1920s, global drought reports from the 1930s, and cooling concerns in the 1970s highlight cycles of warming and cooling that challenge the idea of unprecedented climate change. This article examines these patterns using data from NASA’s Goddard Institute for Space Studies (GISS), a 1923 report on Arctic warming, a 1925 El Niño account, a 1934 newspaper clipping, and a 1978 report on Arctic ice expansion.
The Data: Reykjavik’s Temperature Record
This analysis uses annual mean temperature data from Reykjavik, Iceland (64.1°N, 21.9°W), spanning 1900 to 2017, sourced from NASA’s GISS Surface Temperature Analysis. Iceland’s Arctic location makes it a sensitive indicator of climate shifts, often amplifying global trends. However, comprehensive global temperature records before 1950 are sparse due to limited weather station coverage, so we rely on regional data like Reykjavik’s, paired with historical accounts, to understand pre-1950 climate patterns. You can explore the temperature data for Reykjavik at the NASA GISS Surface Temperature Analysis page (search for Reykjavik station data).
Warming: 1920 to 1940
From 1920 to the early 1940s, Reykjavik experienced significant warming, with temperatures rising from around 4.0°C to a peak of 5.5°C to 6.0°C—an increase of about 1.5°C in two decades. This warming aligns with a broader global phase often attributed to natural factors, such as increased solar activity and fewer volcanic eruptions, which allowed more sunlight to warm the Earth. During this period, the Arctic also saw notable temperature rises, similar in magnitude to later 20th-century trends.
Arctic Warming in 1923: Ice Retreat and Gulf Stream Influence
A Chicago Daily Tribune article from March 1, 1923, titled “Getting Warmer in Arctic Ocean, Maxwell Says,” reports significant warming in the Arctic during this period. Scientific expeditions confirmed that Spitzbergen (now Svalbard) was free of ice, and Greenland’s permanent ice fields had retreated 2,500 miles north of Norway. The article attributes this to a warmer Gulf Stream—a current of water from the Gulf of Mexico flowing northeast across the Atlantic—which was hotter than usual due to excess solar radiation between 1920 and 1922.
The report also notes a high-pressure system over Alaska, influencing weather patterns as far as Chicago, where cold air from Siberia was pushed south. This Arctic warming, driven by natural oceanic and atmospheric changes, aligns with Reykjavik’s temperature increase and underscores the global nature of this climate shift, well before significant human CO2 emissions.
South America in the 1920s: The 1925 El Niño Catastrophe
The 1920s warming wasn’t limited to the Arctic. In South America, the 1925 El Niño event brought catastrophic climate disruptions to Peru, as detailed by Brian Fagan in Floods, Famines, and Emperors. Sea temperatures off northern Peru rose by 6.6°C in just ten days, reaching 28°C in the Moche River—16°C above normal. This warming, which persisted through 1930, drove away anchovies and seabirds, leading to mass die-offs of cormorants and leaving behind foul-smelling hydrogen sulfide residues along the coast.
The warm waters also triggered torrential rains and flooding. In March 1925, Trujillo—a city with a normal annual rainfall of 1.7 mm—received 396 mm of rain, causing devastating floods that swept away infrastructure, farmland, and communities. The Moche River valley experienced massive thunderstorms and cloudbursts, exacerbating the destruction, while the interior of Peru faced drought, highlighting the stark contrast in climate impacts. Fagan notes that El Niño events, often considered local, have global effects, such as monsoon failures in India, further illustrating the interconnectedness of 1920s climate extremes.
Global Droughts in the 1930s: A Wider Perspective
The warming period in Reykjavik, the Arctic, and South America coincided with severe droughts across the Northern Hemisphere, as reported in a Times Daily article from August 4, 1934. Titled “Drought, World-Wide, Bureau Shows,” the article details how crops in regions like Argentina, Australia, Russia, and the U.S. were damaged by prolonged drought. The Foreign Agricultural Service of the Bureau of Agricultural Economics noted that a “lack of moisture during recent months” made seeding operations “extremely difficult,” with significant reductions in wheat yields, particularly in southern Russia.
This challenges the narrative that 1930s heat and droughts, such as the U.S. Dust Bowl, were merely local events. The global scope of these conditions—spanning multiple continents—suggests a broader climate pattern tied to the warming observed in Reykjavik, the Arctic, and South America. Natural variability, not human activity, likely drove these extremes, as industrial CO2 emissions were minimal at the time.
Cooling: 1940s to 1979
Following the 1940s peak, Reykjavik’s temperatures declined sharply, dropping to a low of 3.0°C to 3.5°C by the late 1970s—a decrease of 2.0°C to 2.5°C over 30 years. This cooling period coincided with increased industrial aerosol emissions, such as sulfates from coal burning, which reflect sunlight and cool the planet. Natural cycles, like the Atlantic Multidecadal Oscillation (AMO), also played a role. In the 1970s, some scientists even warned of a potential “ice age” based on this cooling trend.
Cooling Concerns in 1978: Arctic Ice Expansion
A New York Times article from January 5, 1978, provides further evidence of this cooling trend. An international team of specialists concluded that the Northern Hemisphere had been cooling over the past 30 years (1948-1978). They noted a “gradual increase in the massive northern circumpolar vortex” around the Arctic, with its southern extent in 1976 being the largest in a decade and 1% larger than any previous winter. Satellite photography, analyzed by Dr. George J. Kukla of Columbia University’s Lamont-Doherty Geological Observatory, also showed a net increase in snow and ice cover across the Northern Hemisphere.
The article highlights how this increased snow cover reflected more solar energy back into space, exacerbating the cooling during a period of intense solar radiation. This aligns with Reykjavik’s temperature decline and underscores the natural variability at play, as concerns about global cooling dominated scientific discussions just before the 1980s warming narrative took hold.
Warming Again: 1980 to 2017
Starting in the early 1980s, Reykjavik’s temperatures rose again, reaching 5.5°C to 6.0°C by the 2000s and 2010s, matching the 1940s peak. This warming of about 2.0°C to 2.5°C over 30-40 years aligns with global trends often attributed to human-driven climate change. The rise in CO2 levels—from around 330 ppm in 1980 to over 420 ppm today—enhances the greenhouse effect, trapping heat and contributing to global warming, as supported by extensive scientific research. Additionally, reduced aerosol pollution from clean air regulations has decreased the cooling effect of sulfates, further amplifying warming. However, the magnitude of this warming mirrors the earlier cooling in Reykjavik, suggesting that natural variability, such as the AMO, may also be a contributing factor.
Questioning the 1980 Benchmark
The modern climate narrative often uses 1980 as a starting point to highlight global warming, a period that coincides with the end of a significant cooling phase in Reykjavik and increased Arctic ice cover. By beginning at this low point, the subsequent warming appears more dramatic—rising 2.0°C to 2.5°C over 40 years. Yet, the data shows a similar warming from 1920 to 1940, followed by cooling of the same magnitude, all before CO2 emissions were a major factor. The 1920s Arctic warming, 1920s El Niño impacts, 1930s droughts, and 1970s cooling concerns further illustrate that climate extremes are not new.
I do not dismiss the role of CO2 in modern climate change—CO2 levels have risen significantly, from about 280 ppm in 1900 to over 420 ppm today, and it is a known greenhouse gas that contributes to warming. However, the historical record suggests that natural variability, such as the AMO and ENSO, also plays a significant role, and the interplay between these factors is complex. The focus on CO2 as the primary driver may overshadow the contributions of natural cycles, which have driven similar climate shifts in the past.
Reykjavik’s temperature record, paired with 1920s Arctic warming, 1920s El Niño impacts in South America, 1930s global droughts, and 1970s cooling reports, suggests that natural climate cycles, like the AMO and El Niño-Southern Oscillation (ENSO), are significant contributors to climate variability. The 1980 benchmark, following a cold period, may exaggerate the warming trend, but it also coincides with rising CO2 levels, highlighting the need to consider both natural and human-driven factors.
Challenges with Modern Data: Adjustments and Controversy
Recent data shows rapid global warming post-1980, with global temperatures rising about 1.1°C since 1900, most of which has occurred since 1980. Many scientists attribute this to CO2, citing its strong correlation with temperature rise and the predictions of climate models that simulate CO2-driven warming. However, there are concerns about how this data is handled. Modern datasets, including those from GISS and HadCRUT, often apply adjustments to historical records to correct for issues like station moves, instrument changes, or urban heat island effects. Some researchers and skeptics argue these adjustments may smooth out pre-1980 natural variability, making the post-1980 warming appear more pronounced and CO2-driven. For example, adjustments can reduce the amplitude of earlier temperature fluctuations, aligning the data more closely with model predictions. This practice raises questions about the reliability of the data underpinning modern warming trends and suggests we should approach these records with skepticism, especially when they are used to downplay natural variability. Both perspectives—CO2’s role and the influence of natural cycles—deserve careful consideration in understanding climate change.
Looking Forward
Human-driven climate change, particularly through CO2 emissions, is a real concern, and modern CO2 levels can interact with natural variability to influence climate. CO2 undoubtedly influences modern climate, but research continues to unravel the full extent of its role alongside natural variability. Quantifying CO2’s exact contribution remains challenging due to the complexity of climate systems and the limitations of historical data. The Reykjavik data, 1920s Arctic warming, 1920s El Niño impacts, 1930s drought reports, and 1970s cooling concerns remind us to consider historical context. Warming, cooling, and extreme weather have occurred naturally for centuries, and Iceland’s record shows the Arctic’s sensitivity to these shifts. Future climate models should account for both natural variability, including cycles like AMO and ENSO, and CO2 impacts in a collaborative approach to provide a more balanced understanding of our changing climate. We must also critically evaluate the data adjustments used in modern climate records to ensure they do not obscure the role of natural factors, while continuing to refine our understanding of CO2’s contributions through ongoing research.
References
1. NASA Goddard Institute for Space Studies (GISS) Surface Temperature Analysis, Reykjavik station data (64.1°N, 21.9°W), 1900-2017. Available at: https://data.giss.nasa.gov/gistemp/station_data_v4/.
2. “Getting Warmer in Arctic Ocean, Maxwell Says,” Chicago Daily Tribune, March 1, 1923.
3. Fagan, Brian. Floods, Famines, and Emperors: El Niño and the Fate of Civilizations. Basic Books, 1999, pp. 141-147.
4. “Drought, World-Wide, Bureau Shows,” Times Daily, August 4, 1934.
5. “An international team of specialists has concluded…,” New York Times, January 5, 1978.
Credits
This article was researched and written with the assistance of Grok, an AI developed by xAI. Grok played a key role in analyzing the GISS temperature data for Reykjavik, contextualizing historical climate trends, and integrating primary sources, including the 1923 Arctic warming report from the Chicago Daily Tribune, the 1925 El Niño account from Brian Fagan’s Floods, Famines, and Emperors, the 1930s global drought article from the Times Daily, and the 1970s cooling concerns from the New York Times. Grok’s contributions ensured a balanced and well-documented perspective on climate variability.
