An Island of Ice - sign of climate change?

One of the six large ice sheets in the Canadian Arctic has broken free near Ellesmere Island. This is the first time in 30 years such a large Arctic shelf this size (25 square miles) has been observed to break loose. One scientist observed, ""This is a dramatic and disturbing event. It shows that we are losing remarkable features of the Canadian North that have been in place for many thousands of years. We are crossing climate thresholds, and these may signal the onset of accelerated change ahead." This event has obvious implications for climate change as well as, eventually, posing a hazard to shipping if the ice mass stays intact and floats south. It punctuates the series of Arctic ice cover losses discussed in earlier posts, which have raised much concern about polar bears and other animals of the region.
(It should be noted that ascribing this activity to human-caused global warming is not universally accepted. A scientist at the libertarian Cato Institute (http://www.cato.org/) argues the Arctic ice cover was at an unusual peak in the 1970s, and the losses since then may indicate, at least partly, a normal cycle.)
COMMENT: There has been too quick a rush at times to ascribe everything from Hurricane Katrina to the cherry blossoms in the Northeast this month to human-caused climate change. Proponents of quick action on climate change do need to avoid oversimplifying and thus weakening their case. While warming is definitely occurring, the Earth's climate is one heck of a complex system, and that has to be addressed in any scientific understanding of the issue.