An article starts "Global warming could trigger a stand-off between world powers over territory and resources in the Arctic as the ice thaws, Nato's chief warned yesterday." and contains this line that at first glance may seem worryingly conclusive, but is it?
"Some scientists predict that Arctic waters could be ice-free in summer by 2013, meaning that exploration for oil and natural gas will become possible in once inaccessible areas."
"Some scientists" - thousands, hundreds, tens or two...
"could be ice-free in summer by 2013" - could, so could could not be; what odds were given that it "could be"?