Despite decades of research, precisely how the various parts of the solar insolation cycles affect glacial cycles is not known.
Around 2.5 million years ago, Earth started experiencing cycles of ice ages and warm periods, with the last ice age ending about 11,700 years ago. A new study suggests the next ice age might start in about 10,000 years.
Researchers, including a team from UC Santa Barbara, based their prediction on small changes in Earth’s orbit around the sun, which cause significant climate shifts over thousands of years. They studied a million-year record of climate change, examining changes in land-based ice sheets across the Northern hemisphere and deep ocean temperatures. These changes matched with variations in Earth’s orbit of the sun, its wobble, and the tilt of its axis.
The team found a predictable pattern in Earth’s climate changes between ice ages and warm periods. One type of orbital change ended ice ages, while another brought them back.
Lead author Stephen Barker, a Cardiff University professor in the UK, said, “We were amazed to find such a clear imprint of the different orbital parameters on the climate record. It is hard to believe that the pattern has not been seen before.”
Scientists have predicted a link between Earth’s orbit and glacial cycles for over a century, but it wasn’t confirmed until the mid-1970s. Due to dating difficulties, pinpointing which orbital changes are crucial for starting and ending ice ages has been challenging.
Researchers overcame this by examining the climate record’s shape over time, identifying how different parameters fit together to cause climate change.
They found that glaciations over the past 900,000 years follow a predictable pattern. Without human greenhouse gas emissions, we should be in a stable warm period, with the next ice age starting in about 10,000 years.
This predictable pattern allows accurate predictions of past interglacial periods and their durations. It shows that Earth’s natural climate cycles are not random but predictable.
We are currently in the Holocene, an interglacial period. The next ice age is unlikely to happen in 10,000 years due to human carbon dioxide emissions, which have altered the climate’s natural course.
The team plans to build on their findings to create a baseline of Earth’s natural climate for the next 10,000-20,000 years. This will help quantify human-made climate change effects and inform future decisions about greenhouse gas emissions.
Understanding these long-term climate patterns is vital for making informed decisions to address future climate changes.
Journal Reference:
- Stephen Barker, Lorraine Lisiecki et al. Distinct roles for precession, obliquity, and eccentricity in Pleistocene 100-kyr glacial cycles. Science. DOI: 10.1126/science.adp3491
