This chart shows Stratospheric Aerosol Injection could deliver cooling of >2°C by 2070 compared to the optimistic IPCC projection of 4.5 w/m2 without SAI.
That blows carbon-based cooling out of the water. Any time anyone says 1.5°C is passed, just show them this. Geoengineering is urgent. Source: D. G. MacMartin, D. Visioni , B. Kravitz, J.H. Richter, T. Felgenhauer, W. R. Lee, D. R. Morrow, E. A. Parson, and M. Sugiyama, Scenarios for modeling solar radiation modification, Proceedings of the National Academy of Science, August 2022 Fig. 3. High-level results from simulations involving different temperature targets: global mean temperature; SO2 injection rates; land average precipitation minus evaporation P-E; Arctic September sea-ice extent; total column ozone in southern hemisphere (SH), 60 to 90 ◦S in October (in Dobson Units, DU); Global Stratospheric Optical Depth; AMOC; and upper ocean heat content (indicative of thermosteric sea-level rise). From: [email protected] <[email protected]> On Behalf Of Andrew Lockley Sent: Wednesday, 9 November 2022 9:33 AM To: geoengineering <[email protected]> Subject: [geo] Scenarios for modeling solar radiation modification Poster's note: not sure how this got missed. Authors D. G. MacMartin, D. Visioni B. Kravitz, and M. Sugiyama https://www.pnas.org/doi/full/10.1073/pnas.2202230119 Significance The benefits and risks of solar radiation modification (SRM; also known as solar geoengineering) need to be evaluated in context with the risks of climate change and will depend on choices such as the amount of cooling. One challenge today is a degree of arbitrariness in the scenarios used in current SRM simulations, making comparisons difficult both between SRM and non-SRM cases and between different SRM scenarios. We address this gap by 1) defining a set of plausible scenarios capturing a range of choices and uncertainties, and 2) providing simulations of these scenarios that can be broadly used for comparative impact assessment. This is an essential precursor to any international assessment by, e.g., the Intergovernmental Panel on Climate Change. Abstract Making informed future decisions about solar radiation modification (SRM; also known as solar geoengineering)—approaches such as stratospheric aerosol injection (SAI) that would cool the climate by reflecting sunlight—requires projections of the climate response and associated human and ecosystem impacts. These projections, in turn, will rely on simulations with global climate models. As with climate-change projections, these simulations need to adequately span a range of possible futures, describing different choices, such as start date and temperature target, as well as risks, such as termination or interruptions. SRM modeling simulations to date typically consider only a single scenario, often with some unrealistic or arbitrarily chosen elements (such as starting deployment in 2020), and have often been chosen based on scientific rather than policy-relevant considerations (e.g., choosing quite substantial cooling specifically to achieve a bigger response). This limits the ability to compare risks both between SRM and non-SRM scenarios and between different SRM scenarios. To address this gap, we begin by outlining some general considerations on scenario design for SRM. We then describe a specific set of scenarios to capture a range of possible policy choices and uncertainties and present corresponding SAI simulations intended for broad community use. Source: PNAS -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected] <mailto:[email protected]> . To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAJ3C-07rpTxFKKxyPVnOnhyrdqpDsD3284OTy-%2ByAB%2BASmHOOQ%40mail.gmail.com <https://groups.google.com/d/msgid/geoengineering/CAJ3C-07rpTxFKKxyPVnOnhyrdqpDsD3284OTy-%2ByAB%2BASmHOOQ%40mail.gmail.com?utm_medium=email&utm_source=footer> . -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/083901d8f746%24d2a80df0%2477f829d0%24%40yahoo.com.au.
