In order to believe that global warming/climate change (both terms that have been widely used since the 1970s: see
http://www.desmogblog.com/it-global-warming-or-climate-change) is a hoax/fraud one has to believe that there is a worldwide conspiracy between nearly all scientific disciplines and nearly all scientists in organisations and institutes worldwide. Moreover, all the data collected over the last 100 years from temperatures, sea levels, ice cores, geology, and the like would have to have been doctored from the start as well, to construct a huge global hoax from a plan beginning in the early 1900s finally to come to fruition today.
How that might seem logical is beyond me, but I would welcome any published and peer-reviewed evidence to the contrary (and that would certainly merit a Nobel Prize in short order).
One extreme weather event does not prove the existence of Global Warming, nor would a season of such events in any single part of the globe. However, a continued occurrences of extreme droughts, extreme rains, extreme tornadoes, extreme snowstorms and blizzards and extreme heat and cold snaps would comprise an undoubted trend; such a trend is predicted by climate science to occur.
Now, I can post numerous links to concise and articulate comments by scientists, but to keep thing short, here's a summary of responses to points that have been raised many times, some in this thread:
http://planetsave.com/2010/08/13/119-one-liners-to-respond-to-climate-science-myths/.
Here's a well-presented set of visual representations on Arctic ice:
https://sites.google.com/site/pettitclimategraphs/sea-ice-volume.
One of several debunking summaries of the 'no warming in 16 years' meme;
http://www.skepticalscience.com/no-warming-in-16-years.htm.
MJB