Remember the ozone hole?

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Credit: phys.org

Did you know that this year, the Antarctic ozone hole – a phenomenon first identified in 1985 – was the smallest it’s been since 1988?

I missed this bit of science news when it was issued by NASA and the National Oceanic and Atmospheric Administration (NOAA) on November 2.

As you’ll recall, researchers determined that the cause of ozone depletion over Antarctica was the release of chloroflurocarbons (CFCs) and other ozone-depleting chemicals into the atmosphere. We need that ozone: it protects life on Earth from damaging ultraviolet (UV) radiation. According to the U.S. Environmental Protection Agency, “Studies have shown that in the Antarctic, the amount of [UV radiation] measured at the surface can double during the annual ozone hole.”

Here’s the good news/bad news from NASA and NOAA:

“Although warmer-than-average stratospheric weather conditions have reduced ozone depletion during the past two years, the current ozone hole area is still large because levels of ozone-depleting substances like chlorine and bromine remain high enough to produce significant ozone loss. Scientists said the smaller ozone hole extent in 2016 and 2017 is due to natural variability and not a signal of rapid healing…. Scientists expect the Antarctic ozone hole to recover back to 1980 levels around 2070.”

This year marks the 30th anniversary of the international treaty known as the Montreal Protocol on Substances that Deplete the Ozone Layer, an agreement that has led to an abatement of atmospheric ozone depletion. (As yet, I have heard no rumors that the United States intends to abrogate this treaty.) In 1995, the United Nations declared September 16 World Ozone Day (I missed that holiday…).

How did I come around to collecting a few facts about atmospheric ozone right now? Well, a scientist friend of mine asked me a few questions about geoengineering, prompted by a November 8 House hearing on the subject, and, somehow, poking around for information on geoengineering led me to poke around for information on ozone depletion….

The purpose of the hearing was to review the status of geoengineering research in the United States. Witnesses were Phil Rasch, chief scientist for climate science at the Pacific Northwest National Laboratory (one of the U.S. Department of Energy’s nuclear weapons labs); Joseph Majkut, director of climate policy at the Niskanen Center (a Washington, D.C.-based libertarian think tank), Douglas MacMartin, a senior research associate at Cornell University; and Kelly Wanser, director of the Marine Cloud Brightening Project at the University of Washington’s Joint Institute for the Study of the Atmosphere and Ocean.

Geoengineering technology options discussed at the hearing were carbon dioxide removal (CDR) and solar radiation management, or SRM – also known as “sunlight reduction methods” (“marine cloud brightening” is one method of SRM).

Witnesses were appropriately cautious in their statements for the hearing, acknowledging the potential promise of geoengineering techniques as relatively short-term options for mitigating climate change while recognizing the need to continue working on longer-term options to slow global warming. As far as the state of the art of geoengineering, it’s clear that none of the methods discussed at the hearing are ready for prime time. All witnesses recommended more federal funding for research into these techniques.

In his written testimony, Rasch said,  “Research on geoengineering strategies is still in its infancy, but suggests they may represent a promising complement to other responses to climate change…. [They] might help ‘buy time’ for other mitigation and adaptation measures to be put in place. However, it isn’t yet clear whether geoengineering should be part of solution strategies to address observed and anticipated changes in the climate system—we simply do not yet know enough about the potential benefits or risks that might be associated with large-scale deployment of geoengineering technologies…. Even if they are determined to be viable, geoengineering strategies won’t be a magic bullet that eliminates the need for emissions reductions or adaptation measures. While geoengineering technologies could be effective at offsetting some of the effects of climate change, they will not compensate for all of them, and may introduce their own problems.”

(Well said.)

Majkut agreed. Geoengineering technologies, he said, “could be used to prevent some degree of global warming and its attendant effects over short timescales, but there are major scientific questions about the trade-offs associated with using them.”

MacMartin agreed. He stated up front that “reducing greenhouse gas emissions remains the most important component of a strategy to respond to climate change…. Geoengineering…could be an additional and valuable part of an integrated strategy for managing climate change [but it] cannot be a substitute for cutting emissions… Counteracting rising greenhouse gas concentrations would require continually increasing the amount of geoengineering, leading to increased side effects and rapid warming if deployment were ever interrupted.”

Wanser suggested that a federal geoengineering research program “may require $5-10m a year to enable early technology development and field work.”

(I did not observe the hearing, so I can’t comment on Q&A with members.)

I’ve been listening to scientists and engineers talk about geoengineering for more than 30 years. (I’ve also listened to a lot of talk in the aerospace community about the prospect of geoengineering – in this case called “terraforming” – the climate of Mars to make it suitable for human habitation. I think this idea is nuts, not to mention perhaps immoral.) I don’t expect so see a larger federal research effort in geoengineering to develop in the foreseeable future, especially in the current political environment, with an administration that’s refusing to acknowledge the seriousness of climate change.

Geoengineering is technological intervention to change a planet’s climate. We’ve already geoengineered Earth’s climate, by the profligate burning of fossil fuels. I’d say we need to focus on “reverse geoengineering”….

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