Research indicates that without human-induced climate change, Earth may have been poised to enter another glacial period within the next 11,000 years. This prediction arises from an innovative analysis of the planet’s orbital changes and axial tilt, which affect the amount of solar energy reaching Earth.
Historically, Milankovitch cycles have driven the Earth in and out of glacial periods roughly every 41,000 years. However, in the last 800,000 years, these cycles have extended to approximately every 100,000 years. The term “ice age” typically refers to significant periods of widespread glaciation, as well as any time ice existed at Earth’s poles, similar to current conditions.
Scientists have long struggled to clarify how these orbital variations relate to the longer cycles of glaciation, a dilemma known as the “100,000-year problem.” Recent research led by a team from Cardiff University employed a new approach, focusing on the overarching patterns of glacial cycles and their transitions during the warmer interglacial periods. This method allowed them to establish a clearer connection between orbital shifts and ice sheet dynamics.
The research revealed a consistent pattern: every interglacial phase in the last 900,000 years has followed a significant orbital shift where Earth’s axis wobbled at its maximum distance from the sun while simultaneously tilting closer to it, coinciding with a circular orbit phase. This relationship suggests that precession, obliquity, and eccentricity together influence the 100,000-year glacial cycle. “This straightforward rule predicts every major glacial termination event over the past 900,000 years,” stated a researcher from the team.
Based on the established rule, if human-induced warming were absent, the next interglacial phase, succeeding the current Holocene, could potentially begin around 66,000 years from now. However, a glacial period must precede it, indicating that significant cooling would likely be well underway within 4,300 to 11,100 years into the future. The present climate conditions could signify the onset of this forthcoming glacial phase.
Nevertheless, with over 1.5 trillion tonnes of carbon dioxide released into the atmosphere since the industrial revolution, climate experts predict that human emissions will substantially interfere with this long-term glacial cycle. “The quantity of emissions already present will require centuries to millennia to dissipate through natural processes,” a researcher noted. Further studies are essential to refine projections of Earth’s climatic trajectory.
This correlates with earlier modeling efforts suggesting that increasing CO2 levels from human activities will postpone the next glacial period for tens to hundreds of thousands of years. Interestingly, even pre-industrial CO2 levels may have been sufficient to delay ice sheet expansion by approximately 50,000 years, attributed to minimal expected orbital changes and the complex nature of Earth’s climate response.
Topics:
- climate change/
- global warming
