Through the burning wood, human beings have significant contribution of the greenhouse gas emissions, as early as the Roman empire, the researchers said.
The discovery could lead to scientists to rethink models of climate change, it assumes that people are not responsible for most of the greenhouse gases before the industrial revolution some aspect.
"Some people think, emissions started in 1850, we found that human beings have started to influence to the greenhouse effect of more ago, said:" what the research of common the author's Celia Sapart load of blue Utretcht university
Methane is a potent greenhouse gas warming power of carbon dioxide 20 times, Sapart told LiveScience. Forest fire, the wetland and volcanic eruptions and other natural release methane into the atmosphere. But, the person's behavior, such as cattle or the burning of fossil fuels, and now accounts for more than half of methane released.
Dates back to the human have a marked a lot of methane, Sapart and her colleagues analysis from the Greenland ice core. Trapped in the tiny bubbles ice provides a perfect atmosphere for thousands of years ago snapshot, part of the heavy and light carbon isotope (the same element of the atoms, but neutron number different), these air bubble inside, can not only reveal the atmosphere of methane concentration, but told researchers whether gas from forest fires, the wetland or other sources. [giant ice: Greenland glacier photos]
On October 3, in "nature" magazine detailed research, the researchers found that, methane yield high, in about the year 100 BC, the Roman empire heyday, and reduce about A.D. 200 years of empire moved. Methane is released the Romans burned forest land clearing crops and expanding settlements, Sapart said.
This period of time also as it happens and the han dynasty of China, burn wood of the peak period of cast a sword. Once the empire collapsed in 200, cut down the content of methane in the atmosphere.
Methane production in the process also soared European miniature ice age, 1400 years or so, as people burn in wood leave toast, she said. In the whole time researchers study, human activities, such as planting food or from the cold is responsible for 20% to 30% of the organic matter from the burning of methane release. Of course, history of the methane emissions and modernization level, compared to still small.
The research results show that the prediction of climate change may need to be adjusted, Sapart said. Prediction model assumes that benchmark, natural methane emission level how to predict the action will change the future level. Before this, researchers think that naturally occurring events, almost all industrialized methane before.
"All these big goal is to try to predict the concentration of greenhouse gases in the atmosphere in the evolution of the future," Sapart said. "Have already in this period, especially human greenhouse gas emissions of methane, so we need to consider what is natural conditions."




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