Tassie role in climate puzzle

TASMANIAN tree rings and a sediment core from one of our most remote lakes have been used in international research to produce the most complete database on how Earth’s climate has changed during the past 2000-plus years.

The database, collated by international researchers, has provided a tool for climate reconstructions and modelling using data from tree rings, corals, glacier ice and, for the first time, marine and lake sediments.

Researchers gathered 692 records from 648 locations around the world to produce the PAGES2k modelling which shows what the Earth’s climate was like in Roman times and how it has changed since.

Australia contributed five records, all from Tasmania — tree rings from the Huon and celery-top pine trees sourced in the state’s east and west, as well as sediment core from Duckhole Lake, a flooded sinkhole south of Dover.

Tree rings, for example, tend to grow thicker in warmer years, allowing estimates of temperature change during the life of the tree.

The global database was released yesterday in the Nature Scientific Data journal.

Institute for Marine and Antarctic Studies researcher Steven Phipps, who co-authored the study as a member of the PAGES2k Consortium, said the database showed the Earth experienced a long-term cooling trend until the 19th century when things started to warm up sharply.

“This is the most comprehensive database of climate records spanning the past 2000 years that has ever been generated,” Dr Phipps said.

“It will provide new insights into natural climate variability as well as giving us a critically important baseline against which to compare recent climate change.”