Is the Pack Ice Visibly Diminishing ?
By going off on expeditions each year to the Arctic Ocean for the past ten years or so, I have become aware that things are changing. Because the ice is kept in movement, an effect of the Earth's rotation, there are times when the ice breaks up and when the water beneath becomes visible. You can then see the thickness of the ice which lies above the water.
Since we know that 4/5 of the ice is below the surface of the water, we can approximate the total thickness of the ice. Sometimes also, when these huge blocks of ice topple over, we are able to see their thickness as a whole.
This is how we can now see a change in the ice thickness, a change which has occurred not over one year but over the past 15 years. There is a lot more water in the Arctic Ocean in the springtime because the ice melts much more quickly on its sides (a phenomenon likely to spread) but also because the ice is much thinner than it used to be.
I may be wrong, although I don't think so, but I believe there is a significant difference between the overall thickness of the ice today - a difference of perhaps 1.5 metres or even 2 metres sometimes - and what it was fifteen years ago.
