Cosmic rays cause cloud condensation nuclei. They are therefore believed to affect cloudiness, and therefore climate. If we made more cosmic rays, that would likely make it more cloudy. Whether this was a warming or cooling effect would depend on whether it was cirrus or cumulus clouds (NB, sometimes making cirrus ultimately removes water, resulting in less cirrus)
Cosmic rays are almost all protons, with an typical energy peak distribution of 0.3GEv. (4.8×10−11 J). No idea if that's the right energy for CCN, but we can tweak that later. Creating artificial cosmic rays is possible, using a linear particle accelerator. This is similar to an ion thruster, as used in space probes. To affect climate, you'd probably have to get densities of the order of 1/s/sqm (more on that, later). 360 million square kilometers of ocean is 360tn sqm or 3.6x10^14sqm. You don't really want to send particles into people, and the cleaner air over the oceans makes them more effective. A kilo of hydrogen contains 6x10^26 protons. That means 1kg of H2 gives you enough material for 1.6x10^12s = roughly 50 years - so a satellite could easily carry enough material to do the job. Power is 3.6x10^14 x 4.8x10^-11J/s = 17kW - again, well within what a satellite could muster (roughly 100sqm of solar panels, at around 20% panel efficiency (conservative) and 50pc conversion (made up) efficiency). Cheap satellites are about $50m - well within the capabilities of a rich philanthropist. Even if this is not cheap, it's still only perhaps 500m If I'm out by 5 orders (1 ray per sq cm, not per sq m each second), then that's only 10,000 satellites. That's expensive, but not outlandish. Superficially, that would be $500bn at the lower cost, but there is likely a 10x or 100x experience curve cost reduction, meaning the whole programme would be about $5-50bn max. As an alternative, you could use aircraft or balloons, but beam attenuation would be a serious issue. 40km balloons can be launched, albeit with small payloads. They would fly at the bottom of the mesosphere, over 99.9pc of the atmosphere. So maybe beam attenuation would be tolerable, at that height. I don't know how to calculate it, but I'm guessing it would be cms to kms - so not really far enough to make a difference to climate. You could perhaps have mountaintop accelerators with very high powers, and a sweeping beam (like a lighthouse). If the power requirement was GW-range, then maybe the beam range would be a hundred km, or so. That might be enough to work, but it would have some pretty significant effects on local atmospheric chemistry - so probably not a good idea. Any thoughts from anyone? Andrew Lockley -- 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 post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
