Researchers from Scripps, Oregon State, and other schools recently published a study in the journal Nature, showing the results of an analysis of 3,405 meters of Antarctic ice core samples. The study was done at a base constructed on the West Antarctic Ice Sheet (WAIS) Divide, where annual snowfall would reliably accumulate and be subjected to minimal horizontal flowing.
At the coldest time of the last ice age, sea levels are believed to have been 120 meters below today’s levels, and atmospheric CO2 measured around 180 parts per million (ppm). Since then, the level of atmospheric CO2 has tracked upward along with average air temperature and sea level.
This new study was able to track the last ice age from its peak to complete deglaciation; it showed an increase in atmospheric CO2 of about 80 parts per million, taking place over 10,000 years. But the researchers were able to study fine time increments, and they found that there were three events within this deglaciation period, where CO2 levels surged 10-15 ppm during a smaller timeframe of 100-200 years.
The dominant expectation had been that studies would most likely reveal a fairly steady rate of CO2 increase. Thus, in the 10,000 years following the last ice age peak, an increase of 80 ppm would mean roughly 0.8 ppm per century. Instead, the study revealed an even slower average rate of increase in atmospheric CO2, with surges possibly related to other earth processes. “Either the cause of these pulses is at least part terrestrial, or there is some mechanism in the ocean system we don’t yet know about,” said Oregon State paleoclimatologist Edward Brook, a co-author on the Nature study.
The results point out the extraordinarily rapid pace we are seeing today in the increase in our atmospheric CO2 level. Notably, the fastest observed rates were 0.8 ppm per century; today, our average annual CO2 increase is 1.4 ppm per year, thus 180-times the highest rate of increase for atmospheric CO2 level as actually observed in nature. The rate of fossil fuel consumption in today’s automobile-centric communities is historically amazing; in the U.S., each person consumes 21 barrels of oil per year … and that is only our oil consumption (and does not look at our trend to export huge quantities of coal and gas to other nations). The vast majority of this consumed fuel becomes water vapor, CO2, and other pollutants. If our current rapid increase in atmospheric CO2 is connected to human consumption of fossil fuels — and nobody has yet provided credible evidence of any other non-human source — then we will soon feel great pressure to severely cut back on the use of oil, coal, and natural gas.
And, Aviation (as well as all other transportation uses of energy) will be impacted enormously.
- Article (at Scripps.edu) – 10/29/2014
- Phys.org link – slightly enhanced article, plus a link to purchase copies of the study
- Our Addiction to Carbon
- Anthropogenic Carbon Dioxide: Our race past 400ppm
- U.S. Daily Petroleum Consumption, 1973-2012