Would Islands of white plastic be feasible near the north pole to reflect the sun's heat back into space?

I was thinking of ways not to make the oceans such a heat suck from space. They are becoming even in the arctic a heat storage device from sunlight because when white ice melts (like it has been) the blue or green ocean absorbs all the heat directly into the water like a heat battery. This then makes oceans everywhere hotter and causes more evaporation all over the earth, and in tropical climates kills coral reefs and many fish either die from over heating or go deeper or move to cooler waters like is happening all along the coast of California as tropical species move north into California from Mexico, and semi-tropical species that lived off California move north to Oregon, Washington or Canada in the Pacific Ocean.

So, I was wondering the efficacy of putting islands of white plastic on the ocean to reflect back the suns rays to slow down global Warming? The plastic would have to be something that doesn't biodegrade that birds and polar bears could walk on and hunt from and seals could pull up on for relief when they need it. So, I'm thinking about something at least a mile across per island. But, whatever it is made of it would have to be white and reflect the suns rays back into the sky to reduce global warming and the extreme heating of the oceans (especially in the arctic and antarctic right now).