Revised Estimates Show CO2 Levels Had Not Actually Surpassed 400ppm
May 13, 2013

Revised Estimates Show CO2 Levels Had Not Actually Surpassed 400ppm

redOrbit Staff & Wire Reports — Your Universe Online

Update (May 13 @ 1:30 p.m.)

Revised statistics released by the National Oceanic and Atmospheric Administration (NOAA) on Monday have revealed that average carbon dioxide levels at the Mauna Loa Observatory had not surpassed the 400 parts per million (ppm) level as originally reported.

Instead, the average weekly CO2 levels at the Hawaiian facility for May 9 was 399.89 ppm. The agency had initially reported on Friday that the greenhouse gas had reached a concentration of 400.03 ppm, which would have been the highest levels in more than three million years, reports to Bloomberg´s Alex Morales.

“Individual readings at any of NOAA's observation stations are subject to revision on a regular basis. Sometimes a data point is moved to another set when the sets are adjusted for the international date line,” explained Geoffrey Mohan of the Los Angeles Times. “While scientists and environmentalists have used the daily milestone to highlight the buildup of greenhouse gases generated by human activities, it's the rate of rise that is most important.”

According to the NOAA, the average CO2 levels at Mauna Loa for the week of May 5 was 399.52 ppm, up from 397.07 ppm last year during the same week and from 377.85 ppm 10 years ago.

Main Story (May 12 @ 8:26 a.m.)

Atmospheric carbon dioxide levels have surpassed 400 parts per million (ppm) for the first time in human history, according to data released by the National Oceanic and Atmospheric Administration (NOAA).

According to USA Today´s Doyle Rice, NOAA data revealed on Friday the average CO2 levels at the Mauna Loa Observatory in Hawaii over the past five days were 400.03 ppm.

Those readings are important because the Mauna Loa Observatory is “the oldest continuous carbon dioxide (CO2) measurement station in the world,” as well as “the primary global benchmark site for monitoring the increase of this potent heat-trapping gas,” the agency said in a statement.

In comparison, Rice reports carbon dioxide levels were in the 280 ppm range prior to the Industrial Revolution, the era during which mankind first began releasing sizable amounts of the pollutant into the atmosphere by burning fossil fuels.

Experts estimate the last time global CO2 levels were at the 400-plus ppm level was millions of years ago during the Pleistocene Era, added AP Science Writer Seth Borenstein.

“Most experts that really study CO2 amounts estimate that we haven't seen that amount of CO2 in our atmosphere in about 3 million years,” J. Marshall Shepherd, climate change expert and professor at the University of Georgia, told Elizabeth Landau of CNN.

He added that reaching this milestone was not completely unexpected, but that it also serves as “kind of a warning sign or red flag that hey, we really need to tackle this problem. It's happening right before our eyes.”

The NOAA´s Earth System Research Laboratory claims CO2 is the greenhouse gas responsible for more than 60 percent of all greenhouse gas-caused global warming, Rice said. The agency added that the rate of CO2 increase has accelerated from approximately 0.7 ppm per year in the late 1950s to 2.1 ppm per year over the last decade.

Sir Brian Hoskins, the head of climate change at the UK-based Royal Society, told BBC News he hoped the milestone would “jolt governments into action” and increase efforts to battle global warming.

Likewise, World Wildlife Fund chief scientist Jon Hoekstra told Rice the news is “a sobering reminder that the planet we know today will not be the planet we know tomorrow,” and Prof Rajendra Pachauri, chair of the Intergovernmental Panel on Climate Change (IPCC), told The Guardian, “We must hope that the world crossing this milestone will bring about awareness of the scientific reality of climate change and how human society should deal with the challenge.”