July 25, 2012
Ice Core Analysis Shows Warming And CO2 Are Closely Related
Brett Smith for redOrbit.com - Your Universe Online
Scientists have always linked the increase of atmospheric carbon dioxide to a rise in global temperatures, but new research by an international team of scientists connects the cause and effect more strongly than ever before.
According to their report recently published in the scientific journal Climate of the Past, the research team tested tiny bubbles of air trapped in layers of ice around Antarctica for carbon dioxide levels and found that rising levels of carbon dioxide is connected very strongly with the ending of the last ice age.
“Our analyses of ice cores from the ice sheet in Antarctica shows that the concentration of CO2 in the atmosphere follows the rise in Antarctic temperatures very closely and is staggered by a few hundred years at most,” explained Sune Olander Rasmussen, a professor at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.
Previous theories have speculated that a rise in atmospheric CO2 levels lagged the rise in temperature that marked the end of the last ice age by around 1,000 years.
Rasmussen worked in collaboration with researchers from the University of Tasmania in Australia while testing ice cores from five locations throughout the ice sheet in Antarctica. The ice cores represent an archive of temperatures and atmospheric conditions that were present at the time each section of the core was formed. Over the millennia, falling snow hits the ice shelf, freezes and is compressed by snowfall occurring in the following years. Therefore, the deeper scientists tested the ice core sample, the further they were essentially traveling back in time.
A predominant theory states that when Antarctica warms up, stronger winds will whip up over the Southern Ocean. These winds increase ocean circulation and bring more of the CO2-rich bottom water up to the surface. As a portion of this CO2 is released into the atmosphere, it creates a feedback loop for an already warming planet.
“The ice cores show a nearly synchronous relationship between the temperature in Antarctica and the atmospheric content of CO2, and this suggests that it is the processes in the deep-sea around Antarctica that play an important role in the CO2 increase,” explained Rasmussen.
He also warned that this latest evidence could indicate the future global climate if CO2 levels are not brought under control.
“What we are observing in the present day is the mankind has caused the CO2 content in the atmosphere to rise as much in just 150 years as it rose over 8,000 years during the transition from the last ice age to the current interglacial period and that can bring the Earth´s climate out of balance,” Rasmussen said.
“That is why it is even more important that we have a good grip on which processes caused the climate of the past to change, because the same processes may operate in addition to the anthropogenic changes we see today. In this way the climate of the past helps us to understand how the various parts of the climate systems interact and what we can expect in the future.”