Posts Tagged ‘atmospheric CO2 levels’

Self-inflicted Heat

Thursday, August 9th, 2012

An astonishing event has occurred. The Wall Street Journal just ran a regular column acknowledging that the climate is getting warmer, and that the warming is caused by humans.

The record-breaking and devastating heat and drought across America may be the immediate reason for this change in point of view, but a political consensus may be emerging in the US that global warming is real. Not of course on what to do about it, but it’s a start.

Another reason for the possible shift in thinking is the recent research of atmospheric scientist Richard Muller. An out-spoken climate change skeptic in the past, he has received a lot of attention this year because he has changed his mind. His own careful analysis of global temperature data has convinced him that in fact the Earth is warming after all, and that human-produced greenhouse gases are the cause.

Nothing is more convincing than a scientist who looks at the evidence and changes his mind. His impact is huge.

Muller’s analysis of temperature data (the red Berkeley line on the graph, which ignores the data that Muller has been so skeptical about, still shows the same increase in global temperature. He concludes that global warming is real, and human-caused. (

Climate change skeptics, though, have continued to argue that any increase in levels of CO2 in the atmosphere is a natural phenomenon, not caused by the increasing burning of fossil fuels.

So a more remarkable contribution is the research of a NOAA-funded a team of atmospheric scientists at the University of Colorado at Boulder led by John Miller and Scott Lehman, and published a couple of months ago.

In this study, atmospheric gases along the northeast coast of the US were sampled by aircraft every 2 weeks for 6 years. The team then analysed the CO2 in the samples for the presence of Carbon 14. While CO2 from biological sources such as plant respiration is rich in C14, CO2 from burning fossil fuels has no C14, for its half life is only 5700 years, and fossil fuels are of course many millions of years old. So the less C14 in the sample, the greater the contribution of CO2 from burning fossil fuels.

The half life of C14 is 5700 years. CO2 emitted by the burning of fossils fuels, all of which are many millions of years old, has no measurable amounts of C14 left. (

Their results: the increase of atmospheric CO2 from the 280 ppm of the early 1800s to the current level of 390 ppm can only have come from sources lacking C14, and the only sources are the fossil fuels we have burned.

So what are the facts?
– CO2 levels have risen from 280 ppm in early pre-industrial 1800s to 390 ppm currently.
– That increase is human-caused, the result of burning ever increasing amounts of fossil fuels.
– Global temperatures over the same period have been increasing, and the increase is highly correlated with increasing atmospheric CO2 levels.

For the past 400,000 years, global temperature atmospheric CO2 levels have been tightly correlated (

The correlation of global temperature and atmospheric CO2 increases in the past century are also tight. (skepticalscience,com)

– The correlation between increasing global temperature and atmospheric levels of CO2 is so tight that it is almost certainly causal.
– The planet is going to continue to get warmer.
– Fossil fuel companies have proven reserves sufficient to drive CO2 levels and global temperatures to frightening levels (check out Bill McKibben’s recent essay in Rolling Stone).
– Fossil fuel companies a show no inclination to curtail exploitation. We’ll adapt, they say.

We’re screwed.