Does air capture constitute a viable backstop against a bad CO2 trip

Despite all the talk about reducing fossil fuel CO2 emissions, the amount produced each year keeps rising. In 1990, it was 20 billion tons. By 2013 it had risen to 32 billion tons. The content in our atmosphere which has increased from its natural level of 280 parts per million in 1850 to just under 400 parts per million (ppm) in 2013, is currently going up at a rate of 2.5 ppm per year. Recent discoveries of vast amounts of recoverable natural gas and petroleum insure a steady supply for many decades to come. This glut holds down the price of fossil fuel energy, setting back the thrust to substitute renewables. If population continues to rise one percent per year and if per capita fossil fuel energy use continues to rise by three percent per year, then the rate of CO2 rise will reach 5 ppm per year by 2030. Despite these sobering facts, little of consequence is being done to meet this challenge. We continue to nibble when bold action is needed. These nibbles by developed countries have been swamped by increased energy demand in traditionally poor countries. As long as this state of affairs persists, the world will continue to warm and at an ever faster pace. As in none of the areas of concern regarding the consequences of global warming can firm predictions be made, we are, in a sense, flying blind. We suspect that bad weather may lie ahead but can’t seem to find a way to change course. As the late Roger Revelle often said, “we are conducting man’s greatest geophysical experiment.” And that it is. Although there can be no certainty regarding the consequences of the ongoing CO2 buildup, it would be exceeding foolish to disregard the possibility that they will be of a magnitude that will bring about a global crisis. Even if the odds of this happening are small, we should have a contingency plan to deal with it were it to happen. Our military spends billions of dollars each year to maintain the capability to deal with a global war. The NIH spends untold tens of millions of dollars preparing to ward off a pandemic. Yet, we spend only a pittance preparing to cope with a global climate crisis. Were such a crisis to befall us, we would have two major response options. One would be to pull CO2 back out of the atmosphere and bury it in the pore spaces in strata well below the Earth’s surface. The other would be to alter the Earth’s reflectivity in order to reduce the solar input. The former would constitute a permanent solution for it would offer a means to stabilize the atmosphere’s CO2 content at some optimum level. The latter would constitute only a band aid designed to tide us over until a permanent solution could be implemented. Both of these are often referred to as geo-engineering schemes. Although this is certainly the case for albedo modification, I consider CO2 capture and storage to be a form of waste management. For reasons similar to those which forced us into garbage disposal and into sewage treatment, we should bite the bullet and put away the CO2 we produce. Although there are several fledgling projects directed at air capture, only a few tens of million dollars has been spent on them. Three groups in the U.S. (Stolaroff et al., 2008; Choi et al., 2011; Lackner et al., 2012) and one in Switzerland (Baciocchi et al., 2006) have been pursuing research on air capture for over a decade, yet none of them have garnered the funds necessary to build and test a complete and automated proto-type. In the absence of such demonstration units, a very wide range of cost estimates float about. They range from Klaus Lackner’s (2012) claim that it can likely be done for less than 100 dollars a ton of CO2, to an estimate by House et al. (2011) of 1000 dollars a ton of CO2. If Lackner is correct, then, for example, the cost of retrieving the CO2 produced by automobiles would add less than one dollar per gallon to the price of gasoline. This would certainly be affordable. But if the House et al. (2011) estimate were to turn out to be the correct one, then it would add ten dollars a gallon to the price of gasoline. Because of this very wide range, it is widely believed that the cost would lie somewhere in the middle, leading to a consensus cost of Domain Editor-in-Chief Joel D. Blum, University of Michigan