The US needs Canadian territory and radar coverage for its Arctic missile defence plan, but political tension and public scepticism may slow cooperation.

President Donald Trump probably needs Canada's help for his ambitious plans for a massive air defense shield over the United States. The president dismissed Canada's role the "Golden Dome" missile defense project he announced this week,

The North Pole's switch has accelerated in recent years ... When the poles switch, there comes a time when the magnetic shield shrinks to zero before growing again with the opposite polarity.

Magnetic North Pole Shift Accelerates ... During such events, the magnetic shield diminishes to zero before regenerating with opposite polarity. The magnetic field of the Earth is vital for ...

STEPHANE NICOLOPOULOS/AFP via Getty Images The magnetic North Pole, once stable near northern ... of molten iron in its outer core, serves as a shield against solar winds and cosmic radiation.