Today I was heading for some fresh air in the countryside with friends, but ended up… in a coal mine. These days it is a museum, but until recently it was a perfectly real coal mine. I won’t expand on what an utterly bizzare world it is down there. It’s just that on our way out I saw a cage with yellow canaries that reminded me of an expression ‘a canary in the coal mine‘.
Miners (or colliers) used to take canaries down into the tunnels with them so that if dangerous gases such as methane or carbon monoxide leaked into the mine-shaft, the gases would kill the canary before killing the miners (Wiktionary). It has acquired the meaning of ‘a warning of danger or trouble yet to come’ (Wiktionary).
Here are some more examples of how it’s used:
– Whatever one believes about global warming, there is no denying the fact that the earth’s polar regions are undergoing dramatic change as a result of climate change. That has led some to suggest that the poles are the canary in the coal mine as far as climate is concerned (The Economist).
– “Profitability is the canary in the coal mine. It causes a brand to be tarnished in the eyes of distributors who, because of sales cycle times, are extremely sensitive to obsolete inventory (The Guardian).
– For those few economists who spotted the looming recession in time last year, the canary in the coal mine proved to be the labour market. So what is it telling us now? (The Guardian)