While it's impossible to say that any particular event was "caused by global warming, " says Shepherd, climate change loads the deck, making extreme events such as last year's Superstorm Sandy more likely.
So now Tuvalu is demanding a 1.5C degree target, which the UK Met Office has said in another side event here was virtually impossible given its projections based on the current level of emissions.
It is an event that would have literally been impossible just a few decades ago and one that underscores the rising importance of China as a source of growth for many global industries, including sports.
For those of you who are unfamiliar with the term, it derives from an expression that was popular amongst medieval Londoners that referred to an event whose occurrence was believed to be impossible.
U.S. officials will still have to deal with what intelligence experts call "noise" -- the vast amount of reporting and other data that make it impossible to sort out the right information until the event actually occurs and the patterns are known.