Beam me to Planet Gore !
More CO2 INCREASES plankton growth by up to 47% (if for example CO2 increases from 380 to 500 ppm), and more warmth increases growth as well.
More ice coverage (good for polar bears ???) kills the plants that can't get sunshine under the ice....
Yes, more CO2 in the air will increase phytoplankton growth (and only phytoplankton growth, not zooplankton). If the phytoplankton productivity is too great, a “bloom” occurs, followed by a “crash” or massive die-off due to the phytoplankton’s having rapidly depleted the surface nutrients in the water.
The early die-off throws the natural “schedule” off, and thus phytoplankton ultimately ends up being scarce — for a while. Since phytoplankton is the nutrient at the very bottom of the food chain, the scarcity caused by an unusual bloom and die-off affects everything else on up to the top of the chain.
Now, whether this is all happening because of a “vanishing” Arctic ice pack, and whether that “vanishing” ice pack is due to human activity of any sort, and whether there is anything at all that humans can really do to correct the situation — I’ll leave that to the readers to decide...
Google “eutrophication”.
Ah, but the “conveyor”, that deep ocean stream containing huge amounts of dissolved CO2, is running again in the Atlantic, carrying very cold water back down south to the warmer latitudes.