Researchers from institutions in China, Germany, Australia, the United States and Britain wrote: “With the rapid melting of the modern bipolar ice cap, future climate disruptions can be expected .”
The research, led by geologists and climate scientists at China’s Global Environment Facility, shows how the bipolar ice formed – and how it is now melting – and could be and wider climate impacts.
28 researchers have found that the irregular expansion of the polar ice cap – which saw the growth of the Antarctic causing rapid growth in the Arctic – was the cause of the evolutionary event that took place between 700,000 and 1.2 million years ago .
This event, called the Mid-Pleistocene Transition, changed the length of the world’s ice cycles — or the intervals between “ice ages” — from about 41,000 to 100,000 years.
By analyzing historical records of climate and ice, the researchers found that between 1.25 and 2 million years ago, the growth of the Antarctic ice sheet and the southern sea ice led to a cooling in the northern highlands, and caused more moisture to be transported to the northern hemisphere.
This led to the rapid growth of the northern ice sheet, which in turn would have caused the Mid-Pleistocene Transition, changing the length of time that the Earth rotates between its warm and cold periods.
Earth entered an ice age – or warming – about 11,700 years ago, marking the end of our last great ice age.
The team said there were various theories as to why this change occurred, such as a decrease in atmospheric carbon dioxide or a change in ocean circulation, but the proposed mechanisms were has no solid evidence.
Until now, the possible influence of the bipolar ice that grows at different times has not been analyzed as a driver.
Using models of sea surface temperatures, prevailing winds and other variables, researchers could reconstruct changes in hemispheric ice extent and track their progress.
Their construction showed that the expansion of the southern ice sheet preceded the northern one, and that the growth of the Antarctic ice sheet could be “an important precursor to, or even a direct cause of, [the Mid-Pleistocene transition].”
07:25
Cop28 prepares climate assessment at Dubai conference
Cop28 prepares climate assessment at Dubai conference
“Our results highlight strong connections between ice and snow with global implications,” the team wrote.
“Proxy model simulations suggest that the differential development of hemispheric ice sheets is important for understanding global climate change.”
However, the disappearance of the Arctic ice has sparked debate about the potential effects on shipping – including easier navigation, lower carbon emissions and less reliability on Russia’s northern routes.
#Chinaled #study #finds #polar #ice #melt #global #disruption