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So, you've heard the
atmospheric levels of carbon dioxide are rising; CO2 is one of the greenhouse
gases. According to NASA, this graph, based on the comparison of atmospheric
samples contained in ice cores and more recent direct measurements, provides
evidence that atmospheric CO2 has increased since the Industrial Revolution.
(Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)
Over the last 800,000 years atmospheric CO2 levels as indicated by the ice-core data have fluctuated between 170 and 300 parts per million by volume (ppmv), corresponding with conditions of glacial and interglacial periods.
The Vostok core indicates very similar trends. Prior to about 450,000 years before present time (BP) atmospheric CO2 levels were always at or below 260 ppmv and reached lowest values, approaching 170 ppmv, between 660,000 and 670,000 years ago. The highest pre-industrial value recorded in 800,000 years of ice-core record was 298.6 ppmv, in the Vostok core, around 330,000 years ago.
The Keeling Curve, Mauna Loa Observatory, Scripps Institution of Oceanography, UC San Diego, at right
Atmospheric CO2 levels
have increased markedly in industrial times; measurements in year 2010 at Cape Grim Tasmania and the South Pole both indicated values of 386 ppmv,
and are currently increasing at about 2 ppmv/year.
Of course, CO2 is one factor that affects the climate, there are many others. See this page for further discussion.
Now, here is another freaky thought: is the elevated CO2 level slowing the onset of an overdue ice age?
| Claim | Click here for more information | Synopsis | If refuted, by: |
| CO2 levels in the atmosphere are rising | Carbon-dioxide concentrations hit their highest level in 4m years, | Mauna Loa University, as reported by the Economist, May 11th 2013 | |
| Nasa, Graph of Atmosphereic carbon , | The Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era - and of human civilization. Most of these climate changes are attributed to very small variations in Earth's orbit that change the amount of solar energy our planet receives. The current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1,300 years.1 |
