I have random thoughts on my drive to work and one that’s recurred a number of times is “Can you identify climate change based on the weather conditions you see on a daily basis?”
Now I’ll start by saying that I’m not talking about “Wow, I don’t remember a storm this big…it must be due to climate change”. Unusual weather conditions can occur from time to time, but as an isolated incident they may, or may not, be related to a bigger patterns of change.
That said…I’ve been lucky to have worked for the same employer at the same site for 32 years. I’ve also lived within about a mile of my current home for 30 of those 32 years. So as you might image I’ve driven the same few routes 5 days a week, 45 weeks a year for 30 years which means I’ve got a pretty good idea in my mind of the road conditions over those years. One thing I’ve noticed increasingly over the last 5 years or so is that the roads are far more prone to flooding than they ever used to be.
From 30 to 5 years ago I remember two big flooding events leading to roads being impassable or significantly flooded (water of a few inches or more across the entire road). Both were caused by big summer thunderstorm deluges.
Over the last 5 years there have been far more instances of flooding, to the extent that I’m now familiar with 6 different locations along my drive where I’m likely to find flooding. They have become so ingrained in my mind that if it’s been raining I slow down in advance of them because I’m expecting a flood. Where in the first 25 years I’d never thought of these places I’m now finding them flooded many times per year…probably once every week or two during winter over the last 2-3 years.
Now, there could be other reasons for this and I’ve tried to come up with alternative theories. My route is mostly rural, so there aren’t drains/sewers that could be getting blocked. It’s mostly run-off into the verge and the fields beyond. The roads haven’t changed by becoming lower (not sure how that would happen) nor the verges higher (no work has been done to change them). There’s no additional water due to building or other developments near these flood sites…as I said they’re rural and it would be obvious if something big had been built near them.
Anecdotally, I would also say in parallel to this the winters locally seem to have become warmer…but I don’t have data to back that up. It just feels like there are fewer frosty days each winter. That’s to the extent that when talking to family and friends it’s remarked upon when the temperature goes below 0C. It never used to go much below that, but it now seems quite rare to see negative temperatures. Warmer winter weather would tend to give more rain, i.e. more moisture in the warmer atmosphere, which in turn would saturate the fields more, leading to less opportunity for rain water to soak away.
So I’m left wondering…when is something a short term change in weather conditions and when does it become visible climate change? How many years have to pass before we can see the visible effects of climate change?