Sustainable carrying capacity – or what are limits anyway?

Last week, the Royal Society published two papers on the sustainable carrying capacity of New Zealand. I’ve been working on these for a while but, as ever, I don’t feel like I authored them. Instead, they’re a consolidation of discussions with experts, reviewed by yet more experts. There’s a huge list of names of the back of them, go see.

The papers are asking the question of how many people can New Zealand support and copiously failing to give a simple answer, but that’s ok, coz this stuff is hard. For instance, here’s some of the press about the papers:
Kiwis take more than a fair share – NZ Herald
Less television, more gardening suggested – Otago Daily Times

Both those articles miss the point, or rather they are casting about for a simple message – that we’re overshooting the planet’s capability to support us. There’s a bunch of issues with that simple message, which I’ll get around to describing another time, but the primary one is that we know we’re in overshoot, we’ve known that for really quite some time, and saying it again isn’t going to change that.

Instead, what we need is some rethinking. What the papers are trying to get across is that it’s not as simple as trading off between the economy versus the environment within a set of biological and physical limits, which is a shame as that’s the approach that this government is currently using. Seriously, I’ll just quote directly from the Business Growth Agenda report on “Building Natural Resources“, where they put forward one single answer to how to manage the use of natural resources:

The answer is to understand what the sustainable limits are to resource use, and then allocate access rights effectively, promptly and with the right protection to ensure the most productive use of our resources to the benefit of New Zealanders.

Now that’s fine, as far as it goes. If you have a finite and known resource, you can predict how that resource will change with use, you know what the benefits of use and non-use are, then that approach is efficient. That approach is often a big step forward on current ways of managing use. For instance, water for irrigation. We’ve allocated water rights on a historic basis, with no thought to efficient use. Setting up a market and trading those water rights can get a much larger economic benefit from the same amount of water. However, there’s almost always far more to it than simple economic efficiency. Instead, there’s a whole bunch of different trade-offs on many issues between economic, environmental, and social goals, between present goals and future goals, between local goals and global goals, between particular economic goals and other economic goals, and between obvious goals like more food procution and less obvious goals like more resilient food production. Those complexities are enough that thinking in terms of trade-offs is probably not enough, we need better thinking that delivers a whole bunch of benefits.

So what does limit the well-being of New Zealanders? There’s the usual list of finite natural capital and non-renewable resources, of land area, water quantity and quality, climate change, biodiversity, imports of fuel and fertiliser, and wild fisheries. However, each of those limits is a different kind of thing. For a start, we don’t directly benefit from any particular land use, what matters is the benefits we get from particular kinds of land use and what constrains us is how those benefits might change and how willing we are to accept or respond to those changes. So we nationally gain a huge amount of income from using land for dairy, to the point where we’re converting farms from other uses to dairy. With that benefit comes a risk and right now, we’ve a drought, so that income is greatly decreased. What’s the impact on well-being? Well, that depends upon how exposed farmers are to the loss of income, how much debt they have taken on, how much social insurance there is for them. And then there’s the knock-on effects to the rest of society from those changes. There’s no hard and fast limits here, it’s more a question of how vulnerable we choose to be. Thus it makes more sense to talk about constraints than about limits. Limits come from physics and biology; constraints come from our behaviour and our responses.

Each constraint is different – climate change affects us gradually and the impacts ramp up over decades in a fairly predictable way. Dependence upon imports of fuel and fertiliser affect us through price changes over a much shorter period in an unpredictable way. Timescales matter a great deal, the price of phosphorus fertiliser jumped by a factor of eight in 2008 but phosphorus is stored in the soil and farms can get by without it for a year or so, provided the price goes back down as it did. When petrol jumps up in price over a week, most people only store what’s in their tank, need to use that to get to work, and when the price change, they have to suck it up.

In the long term if the prices stay up, we could build a biofuel industry, or shift to electric cars, or more public transport, or more video-conferencing and teleworking, or design communities so we live closer to where we work, or all of these things. Still, each of those options provides resilience but would take time, even if we decided to go for that option as fast as possible. And each of those options takes resources which could be put to other uses, or might be wasted if we don’t need to take up that option. If, in the oil shocks of the 1970s, we had decided we needed to be independent of oil imports, we could have gone hard out for CNG cars using Maui gas. That path turned out to be a dead end, CNG sucks in comparison to biofuels, electric cars, and just more efficient cars, so whatever money we’d spent on that would have been wasted.

So how people and societies can plan for and respond to constraints depends very much on the nature of that constraint. Resilience against climate change looks very different to resilience against petrol supply shocks and that looks very different to trying to keep our biodiversity or keep our freshwater clean or keep growing food or all the other things we want to achieve.

This stuff is hard.

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