Charles David Keeling first implemented the accurate measurement of atmospheric CO2 and it is now 390 and rising.Any global warming greater than two degrees Celsius, or 3.6 degrees Fahrenheit is thought to have unacceptable risks. Limiting Earth's warming to just 2 degrees Celsius hotter by the end of this century is roughly equivalent to capping atmospheric carbon dioxide at 450 parts per million.
The carbon dioxide level will likely to surpass 400 by May 2014. As best scientists can calculate, that means about one trillion tons of carbon can be burned and the gases released into the atmosphere before emissions need to fall to nearly zero. It took 250 years to burn the first half-trillion tons of carbon but we’ll burn the next half-trillion in less than 40.
... Charles David Keeling, a scientist from San Diego. His resulting discovery, of the increasing level of carbon dioxide in the atmosphere, transformed the scientific understanding of humanity’s relationship with the earth. A graph of his findings is inscribed on a wall in Washington as one of the great achievements of modern science.
Yet, five years after Dr. Keeling’s death, his discovery i s a focus not of celebration but of conflict. It has become the touchstone of a worldwide political debate over global warming.
The graph showing rising carbon dioxide levels came to be known as the Keeling Curve. Many Americans have never heard of it, but to climatologists, it is the most recognizable emblem of their science, engraved in bronze on a building at Mauna Loa and carved into a wall at the National Academy of Sciences in Washington.
In later years, as the scientific evidence about climate change grew, Dr. Keeling’s interpretations became bolder, and he began to issue warnings. In an essay in 1998, he replied to claims that global warming was a myth, declaring that the real myth was that “natural resources and the ability of the earth’s habitable regions to absorb the impacts of human activities are limitless.”
Temperature Rising: A Scientist, His Work and a Climate Reckoning