As a scientist I know that all opinions, including my own, may be wrong. I state my opinions firmly because I believe they are right, but I make no claim of infallibility. I beseech you, in the words of Oliver Cromwell, to think it possible you may be mistaken. One principle that we might all accept is that the future is uncertain.
Snow-dumping in East Antarctica would be a good way to stop sea levels from rising. A permanent high-pressure anticyclone over East Antarctica keeps the air over the continent dry and the snowfall meager. To dump snow onto East Antarctica, we must move the center of the anticyclone from the center to the edge of the continent. This could be done by deploying a giant array of tethered kites or balloons so as to block the westerly flow on one side only.
Carbon-eating phytoplankton and snow-dumping are fanciful projects. Like other engineers' dreams in the past, they will probably be superseded by better ideas and newer technologies long before they are needed. They are illustrations of the general principle that antidotes to even the worst-case consequences of climate change will be available if we allow economic growth to continue. The future of technology beyond fifty years from the present is totally unpredictable.
To reach reasonable solutions of the problems, all opinions must be heard and all participants must be treated with respect.
Environmentalism has replaced socialism as the leading secular religion. Environmentalism, as a religion of hope and respect for nature, is here to stay. This is a religion that we can all share, whether or not we believe that global warming is harmful.