Edie: Arctic sea ice may have reached its lowest ever levels, according to environmental campaigners. WWF said 2008 could be the lowest year of summer ice coverage on record, and said that declining thickness among the ice that remains means it may have reached its lowest levels in terms of total volume. Figures are expected to show that Arctic sea ice coverage is similar to last year’s record low of 1.59m square miles. “If you take reduced ice thickness into account, there is …