Lauren R. Stevens: 400 -- Not a magic number



In May of 2013 the amount of carbon dioxide (CO2) in the atmosphere flirted with 400 parts per million. In May of 2014 they are likely to announce their engagement. Meanwhile the United Nations Intergovernmental Panel on Climate Change (IPCC), in a report on CO2 due to be released in March but leaked last month, explains that the longer we wait to do something about the heating of the globe, the harder it will be to mitigate.

Both the National Oceanic and Atmospheric Administration and Scripps Institute of Oceanography take the readings 11,000 feet in elevation, at the Mauna Loa Observatory in Hawaii. That site was chosen because it is far from forests, which absorb CO2, and far from smokestacks, which belch it. Thus it is not unduly swayed. Scientists there measure how much infrared radiation the atmosphere absorbs, a process similar to the way CO2 traps heat. Current readings are above 397 ppm.

The amount of CO2 started to climb steeply with the onset of the Industrial Revolution. It was last below 350 ppm, the amount most scientists believe to be relatively benign, in 1988. Four hundred is not a particularly significant number, except that carbon was last that plentiful three million years ago, when temperatures were some three-to-five degrees warmer and sea level some 30 feet higher. In the immortal words of Bill Cosby, channeling God, to Noah: "How long can you tread water?"


C02 quantity in the atmosphere doesn't rise in a straight line. With spring, vegetation in the Northern Hemisphere begins to suck in CO2, so that after May 9 last year, the amount in the atmosphere decreased slightly. With autumn and winter, it has started to rise again. Furthermore the curve upward has slowed from time to time, raw meat to climate science deniers. Four hundred degrees represented only one day, whereas the readings are usually computed as an average for a month. In a couple years the May average will exceed 400 ppm, no doubt.

The IPCC assesses the likelihood that human activities are responsible at 95 percent, up from 90 percent in a previous report. The panel makes it clear that the world, instead of combating climate change, is increasing its use of the dirtiest fuel, coal, and maintaining fossil fuel subsidies. In short, the primary culprits are coal and cars.

As a result we are already seeing acidification of the oceans, warmer water leading to extreme storms and flooding, and negative effects on agriculture, forestry and human health. Effects on food are being felt sooner than anticipated, with climate change reducing food supply while the world's population increases. As with other aspects of warming, poorer residents of poorer countries suffer the most.

The IPCC recommends support for renewable energy, improvements in the safety of nuclear energy and reduction in the cost of carbon capture technology, by which CO2 could be stored under ground.

At least that's how it looks from the White Oaks.

A writer and environmentalist, Lauren R. Stevens is a regular Eagle contributor.


If you'd like to leave a comment (or a tip or a question) about this story with the editors, please email us. We also welcome letters to the editor for publication; you can do that by filling out our letters form and submitting it to the newsroom.

Powered by Creative Circle Media Solutions