We live today in what geologists and other earth scientists, like climatologists, refer to as the Holocene epoch - the time since the retreat of the last major glaciation, which covered much of North America, Europe, and northern Asia in mile-thick sheets of glacial ice. During this more recent portion of the Holocene is a period, persisting even now, which is often called the Neoglacial, a cooling trend that has followed the Holocene Climactic Optimum.
Yes, cooling.
And, yes, we might note that while people have been around throughout the Holocene, we've only been using fossil fuels in quantity for a few decades now, and nevertheless, most of the Holocene was warmer than our current climate today. Over at Watts Up With That?, analyst Andy May has presented some interesting work examining just this.
The first part of the Holocene, until around 4,000BC was quite warm, at least according to my favorite Northern Hemisphere proxies, the Vinther air temperature proxy (shown black in figure 1) and the Rosenthal Makassar Strait 500-meter proxy of Northern Pacific sea surface temperatures (SST, shown in blue). The lower part of figure 1 shows the number of global glacial advances from (Solomina et al., 2015) as a blue line and the central time and duration of solar grand minima (SGM, black dots) and solar grand maxima (SGMx, orange dots) from (Usoskin, 2017). Before the earliest SGMx shown (at 3860BC) there is not another until 6,120BC. Thus, the Holocene Climatic Optimum (HCO) is likely due to orbital cycles as long assumed and not due to solar maxima.
The Mid-Holocene Transition and the Neoglacial begin with a cluster of six SGMs and four SGMxs, so the sun was highly variable then. It might have played a role, along with the obvious orbital insolation forcings in the initiation of the Northern Hemispheric cooling, but the pattern is ambiguous as to its net effect on climate. Likewise, the 4.2 ka (thousand years ago) climate event does not correlate with the SGM before it or the SGMx after it, it must have other causes.
That's a fair amount to absorb; if you, like me, are a more visual sort, Andy May breaks it down with these charts:
— Ward Clark (@TheGreatLander) February 19, 2026
Notice that the trend line, since the onset of the Neoglacial, has been downward, until very recently, and after a peak well below what looks like the mean, measurements are trending downward again. This isn't due to fossil fuels, but a combination of solar and orbital cycles, cycles for which we know the intervals (the orbital Milankovitch cycles) and can extrapolate them back. And here's the thing: Because this is within the scope of human history, we know of some specific rises and falls in that time frame. Andy May continues:
The spectacular 1177BC Bronze Age collapse (Cline, 2014) follows the 70-year SGM at 1385BC by almost 200 years, so it is unclear how much influence it might have had on that climate catastrophe. The Bronze Age collapse of eastern Mediterranean civilization led to the Greek Dark Age, and it did not end until the Roman Warm Period (RWP) began around 300BC, (some place the beginning later around 250BC). The RWP does not end until 400-500AD.
The Roman Warm Period saw the rise of the Roman Empire, the unification of China by Ch’in in 221BC, and it began just after the death of Alexander the Great. It also saw the rise of India’s greatest ancient emperor, Ashoka the Great who unified India for the first time around 266BC. Ashoka converted to Buddhism and promoted the spread of the religion. This period also includes the life of Jesus of Nazareth and the rise of Christianity.
The Roman Warm Period is notable because it coincides with three consecutive solar grand maxima and contains no solar grand minima. It is also within one of the longest periods in the Holocene without an SGM. The other such long gap, from 1385 to 2450BC, essentially marks the peak of the Bronze Age.
So, major advances in civilization, broadly speaking, happened during warmer periods. Collapses, hard times in general, happened in cold snaps:
The European Dark Age can be identified by lower temperatures in the Vinther record between 500 and 800AD and an SGM at 690AD. The Medieval Warm Period exists between the SGM at 690AD and one at 1030AD and is more of a transitional period into the Little Ice Age than a true warm period like the RWP. The Little Ice Age has no SGMxs and four SGMs, with an exceptionally long one at 1470AD. The Vinther record reaches its coldest point at 1700AD and the North Pacific Rosenthal record is coldest at about 1810AD, so 1750AD is a reasonable Northern Hemisphere date for the modern warm period to begin. The last SGM is centered on 1680AD and it lasts from 1640 to 1720AD.
The data is pretty clear; throughout the Neoglacial, rises and dips in temperature have correlated, more or less, with solar cycles. The Little Ice Age, the coldest interval in the Neoglacial and indeed the Holocene, happened during a period with four solar grand minima and no solar grand maxima.
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The current warming period, on the other hand, began (see the chart) with the strongest solar grand maxima in over 5,000 years.
Yes, this is all a bit turgid, but if you're a science geek like me, it's interesting stuff.
Here's why all this matters: Once again, we see an illustration that Earth's climate is affected far beyond our puny efforts by the Sun, by orbital cycles, by ocean current cycles, and even by the inexorable movement of the crust that we call plate tectonics. The more we learn about these vast cycles, the more we understand that we shouldn't be worrying too much about our carbon footprints; we are small cheese compared to solar cycles and the Milankovitch cycles. We are small cheese compared to the capture of much of the Northern Hemisphere by mile-thick ice sheets, which our ancestors saw first-hand. And, we should note, we are still, biologically speaking, creatures adapted for warm, not cold, climates, so the riseof great cultures in warm periods and the decline in colder periods should come as no surprise.
Yes, the climate has been warming slightly, for the last few decades. Yes, the climate, even since the beginning of the Holocene, has mostly been warmer than now. Yes, human activities have an impact on the climate. But no, there's no reason to panic; there's no reason to dial back our comfortable, high-tech lives to accommodate the complaining of scolds who, in the end, are seeking not safety but control. And no, the Earth has no thermostat that can be set to the planet's "correct" temperature, and if there was, we wouldn't know where to set it.
That's why work like this matters. That's why we should seek to understand these grand cycles, to understand the vast, chaotic cycles and patterns of our planet - so we can decide policy and live our lives, not at the behest of panic-mongers, but in accordance with facts. That's how science is supposed to work.
