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Synchronous Rise in Temperature and Carbon Dioxide Associated with Climate Change

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Borehole in Antarctica
credit: AFP/Getty Images

The greatest climate change in the last 100,000 years was the shift from ice age to the warm interglacial period 19,000 years ago. New research showed temperature rise was closely followed by a rise in carbon dioxide during this shift. Scientists previously thought there was a gap of about 1000 years; new evidence suggested the time delay was just a few hundred years.

The research was carried out by scientists from the Niels Bohr Institute at the University of Copenhagen and the University of Tasmania in Australia. The researchers analyzed ice cores from ice sheets in Antarctica to study the interaction between temperature change and atmospheric carbon dioxide.

Ice sheets act as a blueprint of the atmospheric composition of the past. It is formed by snow that does not melt, but builds up year after year until it is compressed into kilometers of thick ice. During the compression, air is trapped between the snowflakes. As a result, ice contains tiny pockets of ancient atmosphere. The composition of the ice also shows what the temperature was when the snow fell. Hence, the ice is an archive of past climate as well as atmospheric composition.

Five boreholes through the ice sheets in Antarctica were analyzed. The measurements showed a nearly synchronous relationship between the temperature and the atmospheric carbon dioxide. According to Sune Olander Rasmussen, a centre coordinator at the Niels Bohr Institute, the research results suggested processes in the deep-sea around Antarctica played a crucial role in carbon dioxide increase.

Rasmussen explains that it is possible that as Antarctica warms up, it triggers strong winds over the Southern Ocean. These winds pump water vigorously from the deep bottom layers of the ocean where there is a high content of CO2 from the degradation of aquatic organisms that die and fall down to the sea floor. When the CO2-rich bottom water rises to the surface, a portion of the gas is released into the atmosphere. This theory could explain the close link between the rise in temperature and CO2 during the climate change that ended the ice age.

The rise in CO2 also helps to intensify the natural climate variations during that period. It is a greenhouse gas that absorbs and traps heat from the sun, making the Earth warm.

The earth undergoes natural climate variations caused by changes in the earth’s orbit around the sun, the earth’s tilt and the orientation of the earth’s axis. These are called Milankowitch cycles and occur in approximately 100,000, 42,000 and 22,000-year periods. These cycles cause the Earth’s climate to shift between long ice ages of around 100,000 years and warm interglacial periods of around 10,000 to 15,000 years.

According to Rasmussen, the natural cycle of the earth’s climate change is out of balance because of human activities. The global rise in CO2 in the last 150 years is equivalent to over 8,000 years of transition from the last ice age. He asserts that it is vital we have a good understanding of the processes of climate change of the past to be better prepared for the future.

The results of this research were published in the scientific journal Climate of the Past.

[via sciencedaily]

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2 COMMENTS

  1. It is fitting that people begin to realize that CO2 is probably not the cause of global warming. It is the heat emitted by fossil fuels and nuclear power. In 2008 energy consumption was 16 terrawatts. that is ~ 50x10E16 btus per year, enough to potentially raise the atmospheric temperature by 0.17 *F. (The atmosphere has a mass of 530x10E16 kilograms and a specific heat of 0.24 BTU/#-*F.) Actual temperature rise was one fourth that due to cooling by melting of glaciers and photosynthesis.The addition of 60 ppm CO2 probably does not add more heat than it removes through photosynthesis. (5000 btus of energy are removed per pound CO2 due to the chemical reactions). From a heat balance about 10 TW appear to be dissipated by glacial melting ~ 234 cubic miles per year, but I have no idea if this amount of glacial disappearance is real. So much of our focus on CO2 is based on the correlations of CO2/ temperature rise. Correlation is not causation. There is no proof that CO2 is a cause rather than a result of some other factor (increased solar heat during the paleoclimatic period, and industrial energy heat during the present). When fossil fuels are consumed heat is the desired product,, CO2 is a by-product. Our energy policy must recognize that though fossil fuels and nuclear must be phased out, replacing imported fossil fuel with domestic will benefit our energy and financial security without impacting global warming. When renewable energy becomes sufficient, the fossil hydrocarbons can be converted to production of new products.

  2. Do we WANT a President Romney? No of course not so we have to stop driving votes away to Romney when we fear monger our own voting base and their families to a CO2 hell. Is this all worth it, really? In voter’s eye we are the Big Green Fear Machine now. We goofed.
    -Occupywallstreet does not even mention CO2 in its list of demands because of the bank-funded carbon trading stock markets run by corporations.
    -Julian Assange is of course a climate change denier.
    -Obama has not mentioned the crisis in the last two State of the Unions addresses.
    -Canada killed Kyoto with a newly elected climate change denying prime minister and nobody cared, even the millions of scientists.

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