I think one should be very, very careful about throwing iron filings into the troubled waters.
—novelist Ian McEwan
Solutions to the problem of man-made climate change are legion, but none have quite the audacity, the sheer technological chutzpah, of the various ideas that fall under the rubric of geoengineering. This term, which has been around for several decades, refers to the deliberate, planetwide manipulation of the climate to reduce or reverse the effects of global warming. It’s also called planetary engineering, climate engineering, climate intervention, or more to the point (and somewhat hopefully), climate restoration. Scientists who apparently also moonlight as poets call it gardening the Earth.
The scientific, technological, political, and even moral aspects of geoengineering are fascinating, but they’re well beyond the scope of this humble column. My goal here, as usual, is to focus on the new language being generated by geoengineers and others in this burgeoning field, and there’s plenty of it.
The overall goal of solar radiation management (or SRM)—the various schemes to reflect sunlight back into space and thus reduce global warming—is global dimming, which is the gradual reduction in the amount of sunlight reaching Earth’s surface. One way to do this is to increase Earth’s overall reflectivity, which is also called its albedo, so this form of planet hacking is known as albedo engineering. Examples of proposed projects include cloud brightening, increasing the reflectivity of marine clouds (also called cloud whitening); creating a stratoshield through stratosphere doping—pumping sulfur dioxide into the stratosphere to mimic the effects of a volcanic eruption (this is also called the Pinatubo option, after the famous Mount Pinatubo volcano, which erupted spectacularly in 1991, causing global temperatures to drop by an estimated 0.5 °C); lacing the atmosphere with reflective aerosols, which are tiny, reflective metal flakes that could be mixed with jet fuel and deployed through jet exhaust (although this would certainly lead to trouble with a group of conspiracy theorists known as chemmies, who believe that jet contrails are laced with chemicals, a phenomenon they call chemtrails); deploying a space sunshade, which would use space-based mirrors to deflect incoming sunlight; creating cool roofs by painting them white; and Arctic engineering, which aims to maintain or increase sea ice levels in the Arctic, because white sea ice reflects a great deal of sunlight.
The other pillar of geoengineering, greenhouse-gas remediation, aims to take greenhouse gases out of the atmosphere and thus reduce global warming by allowing reflected sunlight to return to space. Carbon is the main culprit here, and carbon engineering usually involves two operations: carbon capture, which is the removal of carbon from the atmosphere (and, depending on where and how it happens, may also be called ocean capture or air capture), and carbon sequestration, which is the long-term storage of captured carbon. These two procedures are linked as carbon capture and storage, or CCS. Strategies include adding nutrients to the ocean to increase the number of organisms that can capture carbon, known as ocean nourishment (when the nutrient is iron, this technique is also called iron fertilization); making artificial trees with plastic "leaves" that capture carbon; creating carbon sinks, reservoirs that store carbon; injecting carbon into underground geological structures (geosequestration) or into biological entities (biosequestration), particularly a form of charcoal called biochar; and pumping carbon into the deep ocean, where it dissolves (ocean dissolution).
The goal throughout is to manage Earth's heat budget, the amount of heat that comes in from the sun less the amount reflected back into space. Will these ideas cause more problems than they solve? Didn’t monkeying with the climate get us into this mess in the first place?
These are tough questions, and I haven’t got any answers. However, we owe it to ourselves to understand what some are calling a rational environmentalism, and knowing the lingo that scientists and politicians are throwing around is a good first step.
This article originally appeared in print as "Hacking the Planet."