The problems faced by New Zealand’s environment, particularly freshwaters and soils are wicked, complex and intertwined. After struggling with these issues for a half a lifetime, it strikes me with great clarity that if you look at each in isolation they seem intractable; but when you grasp that there could be one single solution that addresses them all, then suddenly there is a glimpse of light at the end of the tunnel.
Take, for example, a subset of the many environmental issues facing New Zealand, such as bacterial and pathogen contamination of water and soil, excess nutrients in waters, excess sediment in waterways, freshwater habitat loss, groundwater contaminated with pesticides and nutrients, and the huge loss of the mauri of waterways. Any of these issues appear impossibly hard and/or expensive if evaluated in isolation for costs, or for the difficulty or value of resolution.
But if there was one action available that substantially addressed all of the issues listed above, then the decision would be simple – take that action. When multiple gains can be made for the cost of a single action, and the combined gains far outweigh the single cost of that one action, the next move is obvious. When it comes to the freshwater crisis, a single solution does exist – simply, reducing farming intensity: less cows.
Reducing the number of cows will reduce greenhouse gas emissions, improve water quality, and preserve freshwater habitats. It also looks to be profitable for farmers, because they don't have to waste money on fertiliser to support overstocking. So why don't we do it? Because the entire agricultural industry is invested in either high volume, or in quick-fix solutions for specific problems which become unnecessary if we remove the root cause. But ultimately, its the best way to get our environment back.