Climate

Recent findings on the risk of the collapse of the oceans has brought CO2 back to the top of the list of the most acute threats in what has up until now been referred to as climate change. The new understanding of ocean acidity suggests that we must reduce the atmospheric CO2 level back to pre 1980's levels of 350ppm, or less, within less than 50 years. This is virtually unimaginable within the current framework of negotiations, and represents an urgency that has not previously been understood. To do so will not only require massive CO2 removal, but will require us to do so on a timeframe that will require a transformation of society on a par with the mobilization for WWII. The question will be whether society can recognize that this is necessary to avert the collapse of the biosphere as we know it, and act in time.

There are still enough unknowns in climate modeling that the risk of runaway warming feedback loops due to methane releases in the Arctic remains real. It is also possible that comparatively small increases in global temperature will lead to such acute consequences that the temperature changes which have been trivialized in negotiation will actually lead populations and/or conservation biologists to call for emergency temperature stabilization, particularly in the polar latitudes. For both of these reasons it would be prudent to pursue research into emergency climate protection.

Much of the following, written following the Asilomar Climate Intervention Conference in March 2010 remains relevant, though now in need of an update.

Framing Climate Intervention

A growing number of top climate scientists are gravely concerned that society cannot act fast enough to reduce carbon emissions to avert a serious climate catastrophe. This has led many scientists, who would not have considered the idea ten years ago, to now call for rapid research into climate intervention strategies, or “geoengineering.” Geoengineering refers to the set of ideas and methods for protecting and preserving climactic conditions necessary for human well-being, biodiversity, and the integrity of nature around the world.

There are two broad categories of Climate Intervention: Climate Restoration – efforts to remove carbon from the atmosphere in order to restore the pre-industrial balance of CO2, and more immediately, Climate Protection – efforts to block solar radiation in order to protect the earth from runaway heating.

Climate Restoration strategies involve carbon removal, or carbon remediation, in order to achieve net atmospheric carbon reduction, or even carbon retirement. CR would involve the deployment of large-scale, long-term programs designed to restore the atmospheric carbon level required for climate stability. CR could only begin if we were able to achieve conventional carbon mitigation by reducing, and ultimately eliminating, fossil carbon emissions.

Climate Protection strategies are emergency measures designed to deflect sunlight back into space and thereby reduce the overall heating of the atmosphere. The technical term for this is Solar Radiation Management. The predominant method under discussion is the deployment of stratospheric sulfur aerosols. The term geoengineering has become widely adopted as a synonym for the strategy of deploying stratospheric sulfur aerosols. This method is projected to mimic a cooling effect similar to the natural phenomenon observed after volcanic eruptions. The idea was first proposed by the physicist Paul Crutzen, who won the Nobel Prize for explaining the ozone hole, and who first proposed the idea of nuclear winter, which contributed to the end of the nuclear arms race. Stratospheric aerosols appear to be the cheapest and most easily deployed method of SRM. However, significant research is still required in order to attempt to model any possible unintended effects and to predict overall effectiveness.

The other potential method of Climate Protection involves cloud brightening, spraying a very fine mist of seawater into low ocean clouds in order to increase their solar reflectivity. This method also holds promise, potentially offering a localized effect, which could be used to protect and even restore Arctic sea ice. There are several possible engineering approaches for achieving a cloud brightening effect, but all will require significant additional research to demonstrate the technology as well as to model potential non-local effects.

In general, CR strategies are less controversial than CP strategies. They cover a spectrum from improving land management to restore forest cover and increase net biomass, to algae cultivation for energy or carbon sequestration, to conventional CCS (carbon capture and storage), to the deployment of biochar in soils, to adding limestone to the oceans, to seeding plankton blooms with iron, to deploying artificial trees. Ocean-based strategies may require the most additional research, but the scientific consensus predicts that it would take 1,000’s of years for even the current CO2 level to return to pre-industrial levels on its own without active intervention. There is now little remaining speculation that humanity will need to remove several hundred gigatons of carbon from the atmosphere in order to maintain the balance necessary for the health of the entire biosphere.

All scientific climate predictions include uncertainty bars that show a range of possible outcomes. However, the actual observed warming, particularly in the Arctic, has consistently proven to be at the high-end of that scale, i.e. actual warming is occurring faster than previous worst-case scenarios had predicted.

Arctic sea ice is particularly worrisome as when it melts, the reflective properties of that area change dramatically, going from white, heat reflective ice to black, heat-absorbing water, thus accelerating a runaway feedback loop. Adding to this concern is the large amount of methane bound up in the frozen permafrost and in deposits on the ocean floor. Methane is a greenhouse gas many times more potent and potentially harmful than CO2 if released into the atmosphere. If it were released, it could set off an even more powerful feedback loop that would be outside of human control.

Thus, in addition to the long-term atmospheric CO2 problem, there is potentially a relatively short-term runaway-warming problem centered on Arctic sea ice and methane from melting permafrost and warming arctic lakes and ocean waters. Methane levels appear to be on the increase over the last year or two and we may already be tipping over into that emergency scenario.

Thus, emergency Climate Protection methods look to be essential in order to hold back the loss of Arctic sea ice and methane release. Even in the absence of that acute emergency scenario, there are many climate scientists who now believe that the amount of CO2 already emitted, plus the amount that will almost inevitably be emitted in the future, would be enough to insure that the planet would warm beyond the point required to maintain the stability of civilization and biodiversity unless we act to intervene.

No matter what we do to hold back temperature, the acidity level in the oceans is directly tied to the CO2 level in the atmosphere. So, if we do not act fast enough to achieve deep reductions in fossil carbon levels, while at the same time beginning to aggressively remove net carbon from the atmosphere, we would collapse the food chain in the oceans and with them the whole of the biosphere. Thus, perhaps the most dangerous outcome might be failing to deploy sufficient carbon mitigation under the false security of holding back the warming effect through SRM.

On the positive side, there is at least one scenario where Climate Protection could buy us the time we need to reduce carbon emissions without losing the climate to runaway warming, while Climate Restoration strategies, following aggressive mitigation and conversion to a carbon-free energy economy, could ultimately allow us to remove enough net carbon from the atmosphere to return to a stable CO2 level. This level would most likely prove to be around 300ppm, close to a pre-industrial level, and require us to remove 300-600 gigatons of carbon from the atmosphere over the next 50 to 100 years. The low end of that range would require us to bring emissions to zero immediately, while the high end assumes the overshoot doubles the fossil carbon already emitted.

The Earth is beginning to run a fever, and is in danger of that fever becoming life-threateningly high. To restore our health, we must both prepare to act to temporarily relieve the fever, and then to remove the underlying cause of the illness. Emergency Climate Protection can temporarily relieve Global Fever, while long-term Climate Restoration must ultimately be employed to cure the underlying cause of the disease.