Scientists have long associated excessive greenhouse gas emissions to the continued warming of the climate, but according to new research, these destructive discharges are now being linked to a slowing of the Earth's rotation on its axis as well.
In a study featured in the journal Science Advances, researchers from Harvard University examined how the continued shrinking of glaciers is impacting the rotation of the planet on its axis.
They discovered that as the land ice in the north and south poles shrink as a result of global warming, the weight of bodies of waters across the planet start to shift as well. This in turn causes the Earth to slightly wobble as it spins on its axis.
The buildup of water weight toward the Earth's equator will also cause the rotation of the planet to slow down, similar to how figure skaters begin to slow when they reach their arms out away from their body.
Munk's Enigma
The team's findings helps to solve the mystery of the "Munk's enigma", a scientific theory developed by oceanographer Walter Munk in 2002 that posited that glacier melting had altered the Earth's axis and rotation.
In his paper, Munk considered the effect of the ending of the Ice Age on the environment around 5,000 years ago. This corresponds to a period when glacier melting over the course of the last 15,000 years would have slowed down the planet's rotation.
Munk, however, found out that despite the average sea level in the world has increased by as much as 2 millimeters every year throughout the 20th century, the axis and rotation of the Earth remained unchanged beyond what was caused by the ending of the Ice Age.
"There should've been a whopping great signal and it would be immediate as it only takes days or weeks for that melted water from the poles to shift around the world," Jerry Mitrovica, a geophysics professor at Harvard and lead investigator of the study, said.
Mitrovica and his colleagues discovered that Munk had overestimated the average increase in sea level in his research. Their analysis yielded an average increase of around 1 millimeter to 1.5 millimeter annually during the 20th century instead of Munk's estimate of 2 millimeters.
The researchers believe the slowing of the Earth's rotation will become more noticeable in the coming years as the average levels of the sea continue to rise.
According to the Intergovernmental Panel on Climate Change (IPCC), the average sea level around the world is now set at around 3 millimeters.
Glacier volumes are also expected to slump by around 15 percent to 85 percent by the year 2100, depending on the response of nations to call for a reduction of greenhouse gas emissions and a cessation of widespread deforestation.
Photo: Beth Scupham | Flickr
