Scientists told UK MPs this week that the possibility of a major methane release triggered by melting Arctic ice constitutes a "planetary emergency".
The Arctic could be sea-ice free each September within a few years.
Wave energy pioneer Stephen Salter has shown that pumping seawater sprays into the atmosphere could cool the planet.
The Edinburgh University academic has previously suggested whitening clouds using specially-built ships.
At a meeting in Westminster organised by the Arctic Methane Emergency Group (Ameg), Prof Salter told MPs that the situation in the Arctic was so serious that ships might take too long.
"I don't think there's time to do ships for the Arctic now," he said.
"We'd need a bit of land, in clean air and the right distance north... where you can cool water flowing into the Arctic."
Favoured locations would be the Faroes and islands in the Bering Strait, he said.
Towers would be constructed, simplified versions of what has been planned for ships.
In summer, seawater would be pumped up to the top using some kind of renewable energy, and out through the nozzles that are now being developed at Edinburgh University, which achieve incredibly fine droplet size.
In an idea first proposed by US physicist John Latham, the fine droplets of seawater provide nuclei around which water vapour can condense.
This makes the average droplet size in the clouds smaller, meaning they appear whiter and reflect more of the Sun's incoming energy back into space, cooling the Earth.
On melting ice
The area of Arctic Ocean covered by ice each summer has declined significantly over the last few decades as air and sea temperatures have risen.
For each of the last four years, the September minimum has seen about two-thirds of the average cover for the years 1979-2000, which is used a baseline. The extent covered at other times of the year has also been shrinking.
What more concerns some scientists is the falling volume of ice.
Analysis from the University of Washington, in Seattle, using ice thickness data from submarines and satellites, suggests that Septembers could be ice-free within just a few years.