EESS talk on "The physics and chemistry of aerosols for potential injection into the stratosphere to cool the planet"
Event details
| Date | 27.05.2025 |
| Hour | 12:15 › 13:15 |
| Speaker | Prof. Thomas Peter, Institute for Atmospheric and Climate Science, ETHZ |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
Abstract:
How well do we understand the physicochemical properties of aerosols that are considered for injection into the stratosphere to cool the climate? Almost two decades after Paul Crutzen’s proposition for research on increasing the planet’s albedo by injecting sulfur into the stratosphere, detailed knowledge is still limited about the conversion of sulfur-containing gases (SO2, H2S) into aqueous sulfuric acid droplets, let alone about mechanisms of other potential species such as calcite, alumina or diamond under stratospheric conditions.
While the scientific community’s reaction to Crutzen’s 2006 proposal to research such environmental engineering measures ranged from skepticism to outright rejection, even in the mid-2020s there is little hope that global greenhouse gas emissions can be reduced fast enough to meet the goals set by the 2015 Paris Agreement. Aside from global governance, legal and ethical issues that need to be adequately addressed before any deployment of stratospheric aerosol injections can be considered, we must be prepared to compare the risks and uncertainties of an injection scheme with those of not using it as long as greenhouse gas emissions continue unabated and efficient techniques for negative emissions are not yet within reach. To this end, this presentation examines the physical and chemical aspects of injected particles under the harsh conditions in the stratosphere. Particular emphasis is placed on the impact of aerosol injection on the global ozone layer, comparing injections of sulfuric acid droplets and of solid materials, and assessing the relative risks and uncertainties associated with each.
Biography:
Tom Peter is Professor Emeritus of Atmospheric Chemistry at the Institute for Atmosphere and Climate at ETH Zurich. With his research group, he investigated the fundamentals of aerosols and clouds, their physical processes and chemical reactions, their influence on the composition of the air, on the global atmosphere and on Earth’s climate.
How well do we understand the physicochemical properties of aerosols that are considered for injection into the stratosphere to cool the climate? Almost two decades after Paul Crutzen’s proposition for research on increasing the planet’s albedo by injecting sulfur into the stratosphere, detailed knowledge is still limited about the conversion of sulfur-containing gases (SO2, H2S) into aqueous sulfuric acid droplets, let alone about mechanisms of other potential species such as calcite, alumina or diamond under stratospheric conditions.
While the scientific community’s reaction to Crutzen’s 2006 proposal to research such environmental engineering measures ranged from skepticism to outright rejection, even in the mid-2020s there is little hope that global greenhouse gas emissions can be reduced fast enough to meet the goals set by the 2015 Paris Agreement. Aside from global governance, legal and ethical issues that need to be adequately addressed before any deployment of stratospheric aerosol injections can be considered, we must be prepared to compare the risks and uncertainties of an injection scheme with those of not using it as long as greenhouse gas emissions continue unabated and efficient techniques for negative emissions are not yet within reach. To this end, this presentation examines the physical and chemical aspects of injected particles under the harsh conditions in the stratosphere. Particular emphasis is placed on the impact of aerosol injection on the global ozone layer, comparing injections of sulfuric acid droplets and of solid materials, and assessing the relative risks and uncertainties associated with each.
Biography:
Tom Peter is Professor Emeritus of Atmospheric Chemistry at the Institute for Atmosphere and Climate at ETH Zurich. With his research group, he investigated the fundamentals of aerosols and clouds, their physical processes and chemical reactions, their influence on the composition of the air, on the global atmosphere and on Earth’s climate.
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. Tamar Kohn, LEV