A catastrophic mouse plague, concentrated in the agricultural heartlands of New South Wales and Queensland, is now threatening to destabilise Australia's grain exports with direct implications for British supply chains. Reports from the New South Wales Department of Primary Industries confirm that mouse numbers have surged to densities exceeding 1,000 per hectare in some regions, decimating winter crops and contaminating stored grain. This event is not an isolated anomaly but a predictable consequence of a warming climate: warmer winters and extended droughts followed by heavy rains have created ideal breeding conditions for Mus musculus, the common house mouse.
For Australia, the world's second largest exporter of wheat, the economic damage is severe. The Grains Research and Development Corporation estimates losses already exceed AUD 100 million, with export contracts for barley, canola, and wheat now under threat. For the United Kingdom, which imports roughly 15% of its grain from Australia, this means a tightening of global supply at a time when domestic harvests are already stressed by erratic weather.
The mechanisms are straightforward: mice reproduce exponentially. A single female can produce up to 12 litters per year, each containing 6-10 pups. With abundant food from bumper harvests and mild conditions, the population explodes.
The resulting damage is threefold: direct consumption of standing crops, contamination of stored grain with faeces and urine, and damage to farm machinery and infrastructure. Farmers report that mice have chewed through wiring, hoses, and even plastic grain silos. Control measures have fallen short.
Aerial baiting with zinc phosphide, approved by the Australian Pesticides and Veterinary Medicines Authority, has had limited efficacy. The poison is fast acting but requires multiple applications, and resistance has been observed in some populations. Farmers are now turning to biological controls: encouraging owls and foxes, though predators cannot keep pace with the reproduction rate.
The broader context is one of systemic agricultural vulnerability. Climate models from the CSIRO project that such plagues will become more frequent and intense as the continent warms, with winter temperatures rising by 1.5°C by 2050.
For British consumers, the impact will be felt in rising bread and beer prices, as wheat and barley costs increase on global markets. The UK's National Farmers' Union has already flagged concerns about input costs for animal feed, which could affect domestic meat and dairy prices. This is a story of interconnected systems: an atmospheric driver (warming), a biological response (plague), and a human consequence (supply chain disruption).
The science is clear, and the data are irrefutable. We are watching a slow motion crisis unfold, one that demands not just emergency baiting but a long term reassessment of how we manage agroecosystems in a changing climate. For now, the mice are winning.
And their victory has consequences that will ripple across the globe.
