We wrote that runaway icebergs are killing plankton in the Antarctic by blocking the sun from reaching the surface of the water. This is bad news for more than penguins, because scientists think, eons ago, these tiny shelled sea creatures ended a 200 million year era of extreme ice ages and have protected the Earth from repeating this cycle ever since.
Duncan Graham-Rowe writes in New Scientist that before the evolution of the plankton, polar ice caps covered much of the Earth. Plankton incorporate carbon dioxide into their calcium carbonate shells, removing extra CO2 from the atmosphere. Chemical processes in the sea then dissolve the calcium carbonate from these shells, changing the acidity of the water. This increases the amount of atmospheric carbon dioxide that can dissolve in the ocean, helping to prevent global warming. As Art Bell and Whitley Strieber explain in The Coming Global Superstorm, too much warming can lead to abrupt climate change, producing an ice age.
At first, global warming raises the sea levels, but if freshwater from melting polar regions dilutes the warming gulf stream, it will drop down, leaving the northern hemisphere much colder. This would cause the ice caps to increase once more, leading to lower sea levels, which would cause much of the plankton to die off. Increased ice cover would also reflect sunlight, rather than absorbing it, increasing the cooling effect.
But so far, plankton has saved us?since its arrival millions of years ago, there have been no major ice ages.
NOTE: This news story, previously published on our old site, will have any links removed.