Heatwaves remind us of a climate crisis

Parts of New South Wales are forecast to reach temperatures as high as 48 degrees. In the ACT, the Bureau of Meteorology forecasts a high of 43 degrees on Wednesday. Victoria, currently beset by fires, is experiencing its worst heat wave since the Black Saturday horrors of 2009.

Even those who bask in the heat of summer concede that temperatures in the 40s - let alone those nudging 50 - are ones to hide from in whatever sanctuary of coolness there might be.

They ought to remind us, too, about global warming.

In the current turmoils, from the United States in obvious ways but also from the uncertain political situation in Australia, it is easy to forget that a long-running crisis continues. Global warming is literally a slow burn and needs addressing now more urgently than it did, say, five years ago.

The debate on whether humans burning carbon fuels is the prime cause is now over. The scientific evidence is clear on that (despite the coal lobby's assertions in the United States, echoed by the President himself).

There is still a legitimate debate to be had about how best to address the escalating problem. There are different views about where nuclear power should - or shouldn't - fit in. There are questions about whether wind and solar power can fill the gap left by the necessary demise of coal, and at a cost which citizens are willing to pay.

But there is no doubt that global warming is real and caused by human beings burning fossil fuels. Globally, the decade from 2015 was the warmest on record. The United Nations said that "each of the last four decades has been warmer than any previous decade since 1850".

"The consequences of climate change include, among others, intense droughts, water scarcity, severe fires, rising sea levels, flooding, melting polar ice, catastrophic storms and declining biodiversity," the UN said.

One of the frightening aspects is that scientists still don't fully understand the implications. Our environment is a very complex interaction of linked systems in air, land and water: change one part and other parts change in hard-to-predict ways, with feedback across the system.

A researcher at the Australian National University, for example, has just concluded that changes in global rainfall with the temperature and humidity of the air combined to amplify water-related disasters like floods and droughts in 2025.

"Higher temperatures accelerate evaporation from soil, vegetation and inland waters, producing dry conditions more quickly than before," Professor Albert Van Dijk, who leads the Centre for Water and Landscape Dynamics at the ANU, wrote.

"At the same time, warmer air can hold more moisture, which increases the potential for intense rainfall. Together, these processes intensify both floods and droughts, sometimes in rapid succession."

As climate change becomes more erratic, other unforeseen links will no doubt emerge.

Forgive the analogy, but it is important that we do not put the issue on the back burner. If we do, we are in danger of realising far too late that a liveable planet is something we only remember.

An Australia of unbearable temperatures is not something anybody wants for their personal comfort. It would also be a disaster for the country as a whole, with its disruptive extremes of drought and flood, and the heavy human economic burden they bring.