As the virus spread and the lockdowns began, factories went silent and the skies emptied of aeroplanes and then, in the industrial heartland of China, of smog itself.

NASA published satellite images and heat maps of the skies over Wuhan and Milan, the industrial capital of northern Italy, clear of nitrogen dioxide — the gaseous residue of fuel burnt in cars and trucks, factories and power plants — for the first time in memory.

As though buoyed by the faintest of good news in the unfolding catastrophe, people around the world began sharing photographs of wildlife returning to environments suddenly cleared of pollution — swans and dolphins in Venice’s canals, elephants drunk on pilfered rice wine in Yunnan province. Sadly, as National Geographic reported, a few of the images weren't quite what they seemed. The swans had always been there; the dolphins had been filmed elsewhere.

Similarly, though the sudden drop in carbon emissions is real and measurable, few experts who spoke to this masthead believe the economic shutdown caused by the coronavirus will have any lasting positive impact on curbing climate change. Some fear it might eventually even hamper efforts to reduce carbon.

Read the full article in The Sydney Morning Herald, featuring commentary by Hon. Assoc. Prof Hugh Saddler and Prof Frank Jotzo