Biogeosciences Research Spotlight

Characterizing Interglacial Periods over the Past 800,000 Years

Researchers identified 11 different interglacial periods over the past 800,000 years, but the interglacial period we are experiencing now may last an exceptionally long time.

Source: Reviews of Geophysics


Global climate patterns have undergone a remarkable shift in the past 600,000 to 1.2 million years. Before the transition, glacial cycles, consisting of cold ice ages and milder interludes, typically lasted about 40,000 years—but those weaker cycles gave way to longer-lasting icy eras with cycles lasting roughly 100,000 years. In between the cold ice ages are periods of thawing and warming known as interglacial periods, during which sea levels rise and ice retreats. Here Past Interglacials Working Group of PAGES identifies and compares interglacial periods over the past 800,000 years, including our current era.

Glacial periods give way to interglacials on some occasions when the Northern Hemisphere’s summer solar insolation (the amount of solar radiation received by Earth’s surface) increases alongside corresponding decreases in ice volume and increases in temperature and atmospheric carbon dioxide (CO2). Although the end of an interglacial period is a slow process requiring the sequential reversal of these conditions, the onset of an interglacial period can be relatively fast. Within the glacial periods, there are secondary fluctuations. These are known as interstadial and stadial periods, which occur when glaciers retreat and advance, respectively.

Despite the occurrence of interstadials and stadials, the researchers evaluated the overall strength of interglacials. In total, the researchers identified 11 different interglacials during the study period. In addition, using sea surface temperature and other data, they found that two interglacial periods in particular—marine isotopic stage (MIS) 5 and MIS 11–were particularly strong almost everywhere.

Although most interglacials typically last about 10,000 to 30,000 years, the researchers suggest that the current epoch—the Holocene—may last much longer because of the increased levels of atmospheric greenhouse gases resulting from human activity. The authors predict that this current interglacial period won’t give way to a glacial period for another 50,000 years or so. The only way the current interglacial could end earlier is if CO2 levels were reduced to well below preindustrial levels. (Reviews of Geophysics, doi:10.1002/2015RG000482, 2015)

—Cody Sullivan, Writer Intern

Citation: Sullivan, C. (2016), Characterizing interglacial periods over the past 800,000 years, Eos, 97, doi:10.1029/2016EO047001. Published on 2 March 2016.

© 2016. The authors. CC BY-NC 3.0
  • Austin

    You must remember that we have had these Milankovitch cycles even when we were outside of ice age times, e.g., the Miocene, the entire Mesozoic, the Permian. These cycles do not matter for causing ice ages if CO2 levels are high enough. There is a threshold level of CO2 that once reached will not allow the effect of the Milankovitch cycles to cause polar ice.

  • davidlaing

    The driving factors in the glacial/interglacial cycle are explosive volcanism, which causes global cooling by producing sulfuric acid aerosols in the stratosphere, and non-explosive volcanism, which emits hydrogen chloride and hydrogen bromide, which deplete the ozone layer, letting in more solar ultraviolet-B radiation to warm things up. Both eruptive styles are tied to Earth’s plate tectonic system, which, in turn, is tied to Milankovitch orbital rhythms through gravitational effects. Carbon dioxide has very little effect on Earth’s temperature, as was experimentally demonstrated by Knut Angstrom 116 years ago.

  • Prospector

    So, the news is good. If the CO2/T hypothesis is accurate, we should maintain high concentrations of atmospheric CO2 to stave off the inevitable crush of the next period of glaciation.

  • Thinkingman2025

    They’d better hope this interglacial period lasts a very long time. I’d rather live in a warm period than a cold one. I suspect the majority of Earth’s population would agree. Were a glacial period to start now, a lot of people would either be forced to migrate south, or die.

    • joulesbeef

      the interglacial Holocene looked like it was set to start to end 2000 years ago, and this reversed about 150 years ago, coinciding with the industrial revolution. check the wiki for the holocene and look at the graph, you can see the 2000 years of cooling.. thats not to say we would be in glacier period right now, just we are already slowing down the end of the holocene, which btw matches our current tilt decline.

      • Thinkingman2025

        I know. and the solar cycles seem to be weakening as well. Some say orbital parameters aid the onset of glacial periods, but right now, those oppose such cooling, so maybe we’ll stay warm for a few thousand years more.

  • Joel Gombiner

    Hi Cody,

    It’s not just high CO2 that will cause the present interglacial to last longer than usual. Orbital eccentricity is also low, meaning that precession has a small effect on insolation.

    From the abstract:
    “The combination of minimal reduction in northern summer insolation over
    the next few orbital cycles, owing to low eccentricity, and high
    atmospheric greenhouse gas concentrations implies that the next glacial
    inception is many tens of millennia in the future.”

  • Robert G Quayle

    Below is a decade old item from EOS that touches upon this potentially highly controversial topic:

    Preventing Another Ice Age, Eos, Vol. 87, No. 48, 28 November 2006, JOSEPH STERNBERG, Emeritus, Naval Postgraduate School, Monterey
    DOI: 10.1029/2006EO480006
    Abstract …
    Current concern is focused on the consequences of global warming as the atmospheric level of carbon dioxide (CO2) increases. But adding CO2 to the atmosphere has some potential benefits. As considered in this paper, published research supports the view that a moderate increase in the atmospheric CO2 level could prevent the initiation of another ice age. The amount of C02 resulting from the use of the world’s fossil fuel reserves should be sufficient to provide this protection for thousands of years.