MarketWatch: Declining ice thickness and what is looking like the second lowest coverage on record means that Arctic sea ice may well have reached its lowest levels ever in terms of total volume. The final figures on the minimum ice coverage for this year are expected in a matter of days, but this year’s minimum figures are already flirting with last year’s record low of 1.59 million square miles, or 4.13 million square kilometres. “If you take reduced ice thickness into account, there is probably …