I know we get extreme weather like droughts, heatwaves, floods and storms all the time, but they seem to be increasingly common and widespread.

This year we have seen widespread flooding and lots more rain than usual in Australia early in the year (again!) and across Europe and India since summer, with drought and heatwave in North America as well as flooding in New York because of the hurricane in late October. I have probably missed out other extreme weather events from this year, but is this climate change in action? What do you think?

Nope, it's a sign that the 21st is drawing nearer and that our Mayan overlords are preparing us for our impending doom.

TWISTED TAIL! A THOUSAND EYES! EPA! EPA! EPA!!!

It's a sign of your short memory, only that.

No, at least not without data. Human memory is bad at determining what the multi-year pattern is, and climate change is only on average. For example a particularly mild winter by itself wouldn't disprove a cooling trend.

The IPCC report has some very, very good evidence for anthropogenic climate change and that's based on long-term, quantitative, scientifically tested data.

HA! Simpsons is awesome. 

OP: Yes it is a sign, climate change will lead to an increase in extreme weather events, be it very cold winters or droughts, floods etc.