How many years has sea ice been measured? Since satellites? Any measurement before that can't be too accurate. The few years ,as previoulsy mentioned, amounts to a pimple on an elephants ass. 20 years hardly amounts to any correct measurement of a cycle, when this earth has been around millions of years. Some posters say wait until the La Nina and El Nino cycle play out to determine the actual trend. Will those cycles of nina and nino just disappear after that or will they reappear?