New study uncovers Mars’ role in Earth’s climate cycles

By James Gamble via SWNS

Mars influences our weather by causing deep sea cycles on Earth that last for millions of years, a new study has revealed.

Interactions between the orbits of Earth and the red planet result in a 2.4-million-year cycle.

During these cycles deep currents wax and wane and create whirlpools in the deep, causing periods of increased solar energy and a warmer climate.

Scientists from Germany and Australia used deep-sea sediment records to reveal the cycles, which could help us create more accurate climate models in the future.

The cycles, called astronomical grand cycles, are not linked to the current rapid global warming caused by human greenhouse gas emissions.

The study, published in Nature Communications by researchers from the universities of Sydney and Sorbonne, tackles questions of how geological-timescale climate change affects ocean circulation and how this could help scientists model future climate outcomes.

The researchers sought to find out if ocean-bottom currents become more vigorous or more sluggish in a warmer climate.

They used more than half a century's worth of scientific drilling data from hundreds of sites across the world to understand the vigor of deep-sea currents through time.

The research team used these deep-sea sediment records to check for links between sedimentary shifts and changes in the Earth’s orbit.

They found that the vigor of deep-sea currents shifts in 2.4-million-year cycles which can be predicted due to the interactions between the orbits of the Earth and Mars.

However, evidence for this is rarely detected in the geological record.

Dr. Adriana Dutkiewicz, the lead author of the study from the University of Sydney, explained: "We were surprised to find these 2.4-million-year cycles in our deep-sea sedimentary data.

"There is only one way to explain them: they are linked to cycles in the interactions of Mars and Earth orbiting the Sun.”

Co-author Professor Dietmar Müller, also from the University of Sydney, added: "The gravity fields of the planets in the solar system interfere with each other and this interaction, called a resonance, changes planetary eccentricity, a measure of how close to circular their orbits are.”

As for the Earth, the researchers' findings mean periods of higher incoming solar radiation and warmer climate in cycles of 2.4 million years.

Warmer cycles were also found to correlate with an increased occurrence of breaks in the deep-sea record, related to more vigorous deep ocean circulation.

The study identified that deep eddies were an important component of earlier warming seas.

It is possible that these could partly mitigate the ocean stagnation some have predicted could follow a faltering Atlantic meridional overturning circulation (AMOC), which drives the Gulf Stream and maintains temperate climates across Europe.

"We know there are at least two separate mechanisms that contribute to the vigor of deep-water mixing in the oceans," Professor Müller said.

"AMOC is one of them, but deep ocean eddies seem to play an important role in warm climates for keeping the ocean ventilated.

"Of course, this would not have the same effect as AMOC in terms of transporting water masses from low to high latitudes and vice-versa."

The researchers described these eddies as being like giant whirlpools that often reach the abyssal seafloor, resulting in seafloor erosion and large sediment accumulations called contourites, similar to snowdrifts.

Dr Dutkiewicz added: “Our deep-sea data spanning 65 million years suggest that warmer oceans have more vigorous deep circulation.

"This will potentially keep the ocean from becoming stagnant even if Atlantic Meridional Overturning Circulation slows or stops altogether.”

How the interplay between different processes driving deep-ocean dynamics and ocean life may play out in the future is still not yet known, though the authors hope that their new results will help construct better climate models.