by Lewis Loflin
When we discuss climate change today, the focus often centers on human activity—particularly the rise in CO2 from 280 ppm in 1850 to 420 ppm in 2023, alongside a 1.5°C global temperature increase. This narrative dominates, but history reveals a more complex story. Dramatic climate shifts have occurred naturally, long before industrialization. By examining past changes, early 20th-century records, and the limits of scientific tools, we can better understand whether today’s warming is entirely unique or partly echoes natural patterns.
The Medieval Warm Period (MWP), from roughly 900 to 1300, saw Northern Hemisphere temperatures rise 0.5 to 1°C above the 1850-1900 baseline. Vineyards thrived in England, Vikings cultivated Greenland, and ice core data show CO2 steady at 280 ppm. Then came the Little Ice Age (LIA), from about 1300 to 1850, when temperatures dropped 0.5 to 1°C below the long-term average. Glaciers advanced in the Alps, Arctic sea ice grew, and London’s Thames froze for Frost Fairs. Scientists attribute this cooling to natural factors: reduced solar activity, like the Maunder Minimum (1645-1715), and volcanic eruptions, such as Samalas in 1257.
As the LIA ended around 1850, temperatures began recovering. By 1900, global temperatures had risen 0.2 to 0.3°C, and by 1940, they were up 0.4°C, per HadCRUT5 data (Met Office). Glaciers retreated in the Alps and Scandinavia, and Arctic ice thinned. During this time, CO2 rose modestly, from 280 ppm to 310 ppm. This early warming coincided with the LIA’s fade, suggesting a return toward pre-LIA norms—about 0.5°C above the 1850-1900 baseline—driven partly by natural forces.
Historical records from the early 20th century highlight natural influences. A 1923 Chicago Daily Tribune article reported Spitzbergen (Svalbard) was ice-free, with the Greenland Sea’s ice retreating 2,500 miles north of Norway, linked to a warmer Gulf Stream and elevated solar radiation from 1920-1922. CO2 then was around 300 ppm, barely above pre-industrial levels. In 1912, the Titanic sank after hitting an iceberg at 41°N—unusually far south—amid reports of over 1,000 icebergs in shipping lanes, likely from Greenland’s glaciers calving as the Arctic warmed. CO2 was still near 300 ppm.
These events resemble today’s shrinking Arctic ice and melting glaciers. From 1900 to 1940, global temperatures rose 0.4°C—comparable to the 0.5°C rise from 1980 to 2020—yet CO2 increased only 30 ppm. This suggests natural drivers, like solar activity and ocean currents, contributed significantly then, raising questions about their role now alongside CO2.
The LIA left a legacy of expanded ice across the Northern Hemisphere. When it ended around 1850, and temperatures edged back toward pre-LIA levels, that ice began to melt. This natural retreat aligns with glacier losses and Arctic changes seen in the late 19th and early 20th centuries, like the 1923 Spitzbergen thaw. The 0.4°C warming from 1900 to 1940, with CO2 at 280-310 ppm, fits this recovery pattern, likely aided by rebounding solar output and ocean dynamics.
Greenland offers a nuanced example. Its ice melts at the edges today, raising sea levels, but accumulates inland. The Glacier Girl—a P-38 plane recovered in 1992 from under 268 feet of ice since its 1942 crash—shows this dual process. While Greenland’s margins shrink, its interior gains mass, reflecting a dynamic balance, not a simple collapse.
Today’s 1.5°C rise since 1850 (World Meteorological Organization, 2023) may partly extend this post-LIA rebound. The MWP’s 0.5°C warmth above the 1850-1900 baseline suggests a 1.5°C increase might not vastly exceed historical norms, though it’s accelerated by human emissions.
Ice cores use oxygen isotopes (δ18O) to estimate past temperatures, but their precision is 0.5 to 1°C, and they average changes over decades or centuries. Today’s 1.5°C rise over 200 years (0.08°C per decade) nears this margin of error. Past events like the Eemian (2°C warmer, 125,000 years ago) or the Younger Dryas (a 10°C regional drop in decades) stand out in proxies due to their scale. The 1900-1940 warming of 0.4°C, though impactful, wouldn’t register distinctly in such records. This gap complicates claims that today’s warming is wholly unprecedented, though modern instruments confirm its pace exceeds natural variability alone.
The 1.5°C rise since 1850 tracks CO2’s climb to 420 ppm, but the connection isn’t seamless. From 1950 to 2023, CO2 rose 110 ppm and temperatures gained 0.7°C, yet the trend paused at times—like the 1998-2013 “hiatus” (0.05°C per decade)—and cooled from 1940 to 1970 despite rising CO2. That mid-century dip likely tied to coal pollution’s aerosols, which reflected sunlight until clean air laws (e.g., U.S. Clean Air Act, 1970) reduced them, letting warming resume.
Adjusting for this, the 1900-2023 rise is about 1.1°C (0.09°C per decade), less stark than the 0.2°C per decade since 1980 often highlighted. The 1900-1940 warming (0.4°C, 30 ppm CO2 rise) shows nature’s influence, while post-1970s gains reflect both natural recovery and CO2’s growing role. Natural cycles like the Atlantic Multidecadal Oscillation may still contribute, as they did in 1923, but scientists agree CO2 amplifies today’s trend beyond historical precedents.
Books like Brian Fagan’s The Little Ice Age detail natural swings—the MWP’s warmth, the LIA’s chill—yet pivot to CO2’s modern dominance. This shift reflects a consensus: while nature shaped past climates, human emissions now accelerate warming. The post-LIA recovery may explain some melting, but today’s 1.5°C rise, especially its speed, aligns with CO2’s greenhouse effect, not just natural cycles.
History shows climate has always shifted—sometimes dramatically. The 1923 Arctic thaw at 300 ppm mirrors today’s changes, suggesting nature’s hand. Yet, with CO2 at 420 ppm, science indicates we’re pushing beyond what recovery alone explains. The challenge is disentangling these forces, not dismissing either.
Nature has driven big changes—from the Eemian’s warmth to the LIA’s cold. The post-LIA rebound, starting in 1850, frames much of the warming and melting since, from 1912’s icebergs to today. Proxies can’t fully resolve today’s 1.5°C rise, but modern data confirm it’s real and rapid. CO2 plays a key role, though not the only one—natural factors and past pollution shape the story too. Humanity has adapted to swings before; understanding both natural and human drivers can guide us now, without overhyping or downplaying either.
Acknowledgment: I’d like to thank Grok, an AI by xAI, for helping me draft and refine this article. The final edits and perspective are my own.
