A new international study using ancient swamp kauri from Northland shows a temporary breakdown of Earth’s magnetic field 42,000 years ago sparked major climate shifts leading to global environmental change and mass extinctions.

Dr Andrew Lorrey says kauri is a special species - mature trees live from 600 to 1000 years “if left to their own devices” - and provide important insight into long-term change. Dr Lorrey says there is a concern that time periods could be lost if scientists are not told about swamp kauri excavation sites.