IN previous times, miners carried caged canaries into coal mines.
The canaries would die if exposed to low concentrations of dangerous gases, thus affording the miners the chance to get out of the mine before they too died.
These days the phrase "canary in the coal mine" refers to anything which warns of forthcoming danger.
There are many 'canaries' warning us of the impending dangers of climate change.
First of all is the science. Around 95 per cent of the world's scientists accept that climate change is human-induced.
Climate science uses complex mathematical models, constantly updated by new data, to predict future changes, and there is widespread agreement among very disparate teams of scientists on the predictions generated.
Google "temperature spiral" and you'll get graphs that show how the world's temperature has been rising since the industrial revolution.
Google "CO2 graph NASA" and you'll see how the level of carbon dioxide in our atmosphere, around 180 to 280 parts per million for the past 800,000 years, has shot up to over 400 parts per million in 2019.
These figures are based on agreed facts from reputable agencies and are difficult to ignore.
Then there is the increasing frequency of severe weather events.
The world, and not least Dorothea Mackellar's "wide brown land", has always been subject to "droughts and flooding rains".
Yet more and more often one hears of 100-year records being broken, and old folks who know the land and the climate saying they have "never seen a drought or flood like this".
Wildfires are occurring earlier and cyclones are more intense.
Our own mayor, Bobby Bourke, no spring chicken himself, remarked recently: "I have never seen it this bad in Bathurst. We have had a couple of droughts but not this bad."
Warmer weather results in sea-ice and glaciers melting and sea levels rising.
Ask our Pacific neighbours about this. Their islands, only a few metres above sea level, are already being inundated by the modest sea level rises that have occurred so far.
Do we need more significant rises threatening inundation of seaboard cities like Sydney, London and New York before we believe this is happening?
We ignore these canaries at our peril.