One of the biggest issues with assessing climate change is how we link climate with weather. We know that climate change ought to produce a corresponding change in weather patterns, but we can't demonstrate that individual weather events are a product of climate change and in the minds of most people weather is what we see (natch), not climate.
So, although the Russian president attributed the recent heatwave to climate change, even New Scientist are far more cautious in doing so.
I think the way to resolve this is not to look for demonstrations of extreme events, but to relate all weather events to climate change. This is how:
Essentially, if climate change is being driven by global warming then what we're saying is that there's more energy present in the earth's system, because heat is a measure of energy and temperature is: ºC = J/(Kg * SpecificHeatCapacityOfAtmosphere).
Extreme weather events are powered by the extra energy in the system. So in a sense all we have to do to relate weather events to climate change is calculate (even roughly) the energy in any particular weather event and add it all up. We can then provide a total and a probability that this total thus far lies within the natural variance. We make these two figures part of normal weather forecasts.
This technique will work well for relatively local weather as well as global weather and as weather events add up to a convincing argument for climate change people will want to see the Climate Change Weather Index falling - they'll want to do what it takes to reduce flooding, heatstrokes, air-conditioning and blizzards.