EU-ISOTREC

Climatic and environmental changes in the Eurasian Subarctic inferred from tree-ring and stable isotope chronologies for the past and recent periods

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 Obiettivo del progetto (Objective)

'The goal of this project is: • to develop a comprehensive description of the climatic and environmental changes in the Eastern Taimyr [72N-102E] for the warmest periods during the Holocene using tree ring width, latewood density, cell size, carbon and oxygen isotope data in wood and cellulose; • to improve our understanding of the physiological response of larch trees to environmental changes in the Eurasian north. We propose to investigate three periods, which are characterized by high temperatures during the Holocene: • the natural warm period BC 3700-3800, with an average temperature, which was three degrees higher than at present; • the Medieval Warm period AD 950-1150, with a similar rise in temperature compared to today; • the current period AD 1945-2006, which is characterized by the highest level of atmospheric carbon dioxide due to anthropogenic activities besides a temperature increase. The work will be conducted in three major fields: 1. Climatology – analyses of statistical relationships between climatic parameters (temperature, precipitation, relative humidity, and vapor pressure deficit) and carbon, oxygen isotope data during the current period. Comparison of isotope chronologies along the Subarctic latitudes from Yakutia to Sweden with Greenland ice core and pollen data. 2. Physiology - investigation of the physiological response of trees to environmental changes during the current and past periods based on a combined carbon and oxygen isotope fractionation model developed by Scheidegger et al. (2000). 3. Modeling – the new isotope and tree ring chronologies will be used to verify the ecophysiological model [Hemming et al. 2001; Vaganov et al. 2006] for the current period and to extend the model for the past to infer new environmental information (e.g. on water use efficiency).'

Introduzione (Teaser)

Scientists have conducted climate reconstructions over millennia using the isotope signals stored in tree rings.

Descrizione progetto (Article)

Finding evidence that describes past long-term climatic changes is key to understanding the future impacts of climate change on ecosystems. This data can help unravel the natural causes and human influences behind temperature shifts and help the EU prepare for potential environmental disasters.

The EU-funded EU-ISOTREC project aimed to describe the climate changes, and the physiological response of trees to environmental changes, during current and past geological periods. This was done using classic methods combined with modelling and analysis of tree-ring width, density and isotope signals, which hold information about large-scale temperature patterns.

Scientists found that the current rate of warming in the Siberian north has occurred before, millennia ago. However, they found global warming has had a greater impact on the forest ecosystems in the northern parts of central Siberia than in north-eastern Siberia.

Furthermore, during recent decades, the trees have responded physiologically to a water shortage, and this is expected to continue increasing along with regional temperatures. Consequently, project research suggests these trees will experience severe drought stress and be exposed to increased fire events as well as insect attacks.

These findings could inform tools to help develop effective strategies for managing Russian forests. Documenting the management decisions in this region means it could also be used as a European case study for managing large-scale impacts of climate change.