Even if you’ve never heard of Jevon’s Paradox, chances are you’ve experienced it. Never been on a congested motorway? Yeah, right! Almost every arterial feeder into almost every city was built to tackle congestion. And after several years of construction and a few years of free-flowing traffic, virtually every such arterial snarls right up again.

Why? For traffic, that’s often called “induced demand”. But it’s also an example of Jevon’s Paradox in action: basically, making something more efficient should mean people can do the same as before but spend less money or time doing it, but the reality is often the opposite; the new “efficiency” attracts even more usage, so the overall effect is a worsening of the original problem.

And the importance for tackling climate change? We know we’re on a quest to reduce climate impacts, and two of our biggest sources of greenhouse gases are transport and agriculture. One seemingly logical “reduction” strategy is improving efficiency, eg. fewer vehicles driving on the roads or more milk per cow.

We know the government is pushing for time-of-use (aka congestion) charging, and bring it on, I say. Stockholm has a fascinating experience in that: in the face of overwhelming public opposition, it introduced a six-month trial (cheap, at €2/day). Instantly, traffic dropped 20% and congestion vanished. Then, at the end of the trial, it instantly returned.

But in the subsequent referendum, the same public overwhelmingly voted to reinstate it, ie. voted to pay for access they previously had free, and congestion vanished again.

Amazingly, the adjustments were so varied that researchers couldn’t pinpoint what had changed, and individuals thought they were travelling just as they always had.

Looking at dairy, increasing the yield per animal seems great. And on the face of it, New Zealand has impressively low “emissions intensity” milk (low emissions per litre).

But if the objective seriously is to reduce our overall national methane emissions, we need to take a whole-of-industry view. More milk per cow, leading to lower emissions per litre, could mean fewer cows (and so fewer emissions) for the same milk production. Yay! We’d have made serious inroads into our national emissions.

But MPIE’s publication AgMatters (at tinyurl.com/AgMatters) notes: “However, emissions reduction targets both in New Zealand and internationally are framed in absolute reduction terms, not reductions in emissions intensity.”

A steady stream of emissions intensity reductions (1% per year) is eclipsed by the expanding dairy herd, and since 1990, overall dairy emissions have more than doubled.

Now this isn’t all due to Jevon’s Paradox, but it’s a case of our economic system squandering an opportunity to make things 30% better, and instead making them 130% worse.

So what’s the lesson in all this, with dairy going the wrong way and the good people of Stockholm not even thinking they had changed behaviour? Perhaps it’s to challenge ourselves to make sure “less” actually means “less,” and welcome a chance to do things differently in the quest to secure a liveable future.

Lindsay Wood, MNZM, runs climate strategy company Resilienz Ltd. He is active in policy, and on IT tools for decarbonisation, and speaks, writes and broadcasts widely on climate issues. In 2024 he was made a Member of the New Zealand Order of Merit for services to climate awareness and environmental sustainability.