Scientists have outlined a controversial plan to refreeze the North and South Poles, and dial down the global thermostat.
They say high-flying jets could spray microscopic aerosol particles into the atmosphere to reflect sunlight and cool the melting icecaps.
Around 175,000 flights a year would be needed, releasing millions of tonnes of carbon dioxide.
But a former UK chief scientist backed the plans, telling Sky News that polar warming is now critical - and refreezing the ice could hold back the rise in global sea levels.
The new study was led by Wake Smith from Yale University in the United States.