Every year, throughout New Zealand, many thousands of tonnes of organic "waste" is dumped into landfills or is inappropriately discharged to land. Once dumped much of this green waste material breaks down in an uncontrolled manner and releases methane greenhouse gases into the atmosphere and pollutants into our waterways. Methane is estimated to be 25 times more damaging to the ozone than carbon dioxide (CO2). Meanwhile most of New Zealand's cultivated soils have been steadily deteriorating. This is due to both to a decline in soil organic matter and a depletion of minerals and nutrients.