I saw the catchy Phys.org news title Artificially cooling planet 'risky strategy,' new research shows and then looked at the open access article, in Nature Communications (14-Nov-2017 online) Impacts of hemispheric solar geoengineering on tropical cyclone frequency, Jones et al. doi:10.1038/s41467-017-01606-0
Solar geoengineering refers to a range of proposed methods for counteracting global warming by artificially reducing sunlight at Earth’s surface. The most widely known solar geoengineering proposal is stratospheric aerosol injection (SAI), which has impacts analogous to those from volcanic eruptions. Observations following major volcanic eruptions indicate that aerosol enhancements confined to a single hemisphere effectively modulate North Atlantic tropical cyclone (TC) activity in the following years. Here we investigate the effects of both single-hemisphere and global SAI scenarios on North Atlantic TC activity using the HadGEM2-ES general circulation model and various TC identification methods. We show that a robust result from all of the methods is that SAI applied to the southern hemisphere would enhance TC frequency relative to a global SAI application, and vice versa for SAI in the northern hemisphere. Our results reemphasise concerns regarding regional geoengineering and should motivate policymakers to regulate large-scale unilateral geoengineering deployments. (emphasis added)
The paper seems to warn against single-hemisphere solar geoengineering. Was that the plan to begin with, and nobody until now thought that cooling one hemisphere but not the other one might be problematic?
Or is this paper simply stating something more common-sense, for example "if you do it wrong, it won't work right".
Was there in fact any plan for unilateral geoengineering deployments before this was published, or is there a bit of grandstanding along with the science?