"Two issues remain: the concern that tephra could harm marine ecosystems – an area which Longman concedes needs investigation – and the fact that marine dumping

"Two issues remain: the concern that tephra could harm marine ecosystems – an area which Longman concedes needs investigation – and the fact that marine dumping in general is banned under the 1972 London Convention on marine pollution." What about "how do we haul all that tephra out into the ocean without producing a bunch of pollution in the process"? Are there solar-powered bulk carriers that we can load up with solar trucks, diggers and forklifts? I assume you could at least get to break-even with that process if you optimized everything enough, but then you start wondering about the materials costs and environmental impact of all the special-case equipment...