I offered a few thoughts back here on the connexions between extreme weather and climate change. This topic continues to be the subject of much investigation and the links are many and complex. Nonetheless, a few metaphors are becoming commonly accepted by scientists attempting to communicate their findings.
The first is the image of a baseball player on steroids. Adapting it for use in Commonwealth nations, let's talk about a cricketing batsman on steroids. Taking the drugs improves his muscle condition and makes it possible for him to hit balls harder. While it is not possible to say whether this or that six is the result of drug-enhancement, it is nonetheless possible to see that the player is now hitting more sixes than he was before he started taking drugs. The odds have shifted in favour of bigger shots. In the same way, we're getting weather on steroids, with greater odds of dangerous extremes.
The second commonly-used analogy, mentioned in this video, is the idea of "loading the dice". Weather is always variable, just as rolling a pair of (six-sided) dice will give you results ranging from 2 to 12, with 7 being most common. But if you take one of those dice and add a dot to each side, so that it now ranges from 2 to 7, then you'll still see a lot of variation, including the occasional low number. But 8 will now be most common, and it will be possible to roll a 13. Some of the events we've seen in the last handful of years around the globe have been the equivalent of 13s, standing as much as six standard deviations above the average (using the period 1950-80 as a baseline). Indeed, if we just look at events that are three standard deviations or more above the average, then statistically on an unchanging planet, we'd expect (on average) just 0.3% of the globe's surface to be experiencing such conditions at any one time. Yet over the last decade, the average has been about 10% of the planet's surface facing such extreme conditions. In fact, if we want to be a little more accurate, then rather than painting an extra dot on all the sides of one die, it is as though we have taken one of our pair of six-sided dice and replaced it with an eight-sided die. The point is not only has the average increased and upper extreme become more extreme, but the range of possible weather experiences has widened, leading to greater variations in temperature and precipitation. Not only are the extremes hazardous to human health and ecosystems (both natural and managed), but greater variability is now also becoming more widely accepted as harmful.
All our weather now occurs in an atmosphere increasingly shaped by human activities. There is no "natural" weather any more. We are moving into a new regime that includes higher numbers, and 13s will not be the end of it. We've only warmed about 1/5th the projected warmth of our current trajectory within my daughter's lifetime and perhaps 1/10th of the likely long-term warming.
The chances of the ball being hit out of the park keep increasing.
UPDATE: After posting this, I came across this post that examines this topic in more detail and includes the following very helpful video.