"You can' t blame global warming for a single episode of bad weather"

* Vehicles drive along a flooded street in Guangzhou, South China's Guangdong Province August 14, 2007. Image from China Daily.

Whenever a weather event (heat wave, flood, drought, etc) appears in the media, somewhere someone points the finger at climate change caused by humans. These indictments are often answered with the widespread mantra: "You can' t blame global warming for a single episode of bad weather".

Can we say that these particular extreme weather events are caused, or at least are aggravated by global warming?
Has anything changed in the understanding of climate scientists, or about the attribution "the anthropogenic fingerprint" of these phenomena?

Regarding the climate itself, the danger is that we have lost adaptability to changes in climate: We are no longer nomadic society that can rely on migration as an adaptation measure to climate change. We are a sedentary society with great wealth invested in real estate and infrastructure and with borders and sovereignties which impede migration. This is the climate we have adapted to. Any change in the same supposes intrinsic hazards and must be studied.

We will review some of the phenomena supposed to increase in frequency and scope and treat some specific cases from an academic point of view to try to shed some light on the topic.