As any tramper knows, few things are more dispiriting than slogging up what should be the final slope, only to discover there's a higher ridge still to climb.
So it is with the fight against Covid-19.
While we're still working our way uphill, hoping the skyline ahead really is the summit, when we get there we're going to face another uphill battle -- against climate change and environmental degradation.
Given what the world is going through, it would be tempting to ignore that next struggle.
After all, we're spending all our money right now, coping with the immediate danger.
What resources will we have left to fight another risk that, so far, is still mostly over the horizon?
And anyway, haven't businesses, farmers and ordinary taxpayers suffered enough, without incurring the extra cost of averting climate calamity?
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But while the coronavirus battle is right here and right now – literally in our faces – nothing has changed about the need to reduce the harm humankind is doing to the environment.
Shutdowns have delivered a brief respite in greenhouse gas emissions, but it's only a blip in a rising trend. And the more successful economic stimulus packages are, the more likely it is that emissions will rise again.
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Costly as coronavirus is, the danger is that decades from now, that cost could seem insignificant compared with the cost of climate change – in deaths caused directly by heatwaves, the spread of tropical diseases, famine resulting from changing weather patterns, and rising sea levels.
If some of those dangers can seem remote from New Zealand, the economic costs of climate change are less easy to ignore. It's easy for city dwellers to forget, but we've just had a reminder of those risks, in the drought that disrupted farming in many regions.
Past droughts have cost this country billions of dollars a year. That's not in the same league as the cost of the coronavirus battle but it doesn't take a vivid imagination to fear the impact of a succession of severe droughts. Or a string of major storms. Or Australian-scale bushfires. Or new agricultural pests, making themselves at home as the country gets warmer.
While it's never possible to say with certainty that this drought or that storm was the result of manmade climate change, it is possible to say that climate change makes more unseasonal weather more likely.
As a nation that relies on agriculture – suddenly, even more than we already did – the danger is obvious.
Globally, the risks are even more stark. In 2014, the World Health Organisation estimated that climate change would lead to about 250,000 extra deaths per year between 2030 and 2050. Individuals can make a difference and maybe some habits learned in lockdown – working from home, flying less – will help. But in the end, government action is the only thing that will get us up that next slope.
Whatever the scale of the current crisis, governments can't escape the need to boost efforts to combat climate change, keep exhorting others to do the same and make sure stimulus-funded projects don't lock us into an even higher-emissions future.