Brøgger Seminar Series
Global warming happens in spring – The active and passive role of vegetation greening during rapid climate change 

When? 13 January, 15h15 | Where? DeGeersalen, Geovetenskapens hus

 

Northern Hemisphere lengthening of the vegetation growing season is related to regional warming under industrial CO2 increase. This climatic trend has profound consequences, ranging from global carbon storage to biodiversity, from agriculture to public health. Accurate satellite based time-series observations of growing seasons are restricted back to 1982 when satellite monitoring began. Scarce older plant phenological observations provide data for the past ~150 years. Vegetation and climate modelling efforts both use satellite based documentation as input data. Therefore, performance weaknesses are likely related to the short reference data records.

Palaeophysiology of plants sets a new conceptual, data-constrained assessment of the intimate climate-phenology link through time. Uniquely combining our palaeoecological and plant physiological expertise, this approach comprehensively investigates the active and passive role of the vegetation growing season in climate change.

Plant physiological field and chamber experiments provide a) extensive information on growth patterns in subarctic plants under controlled environmental conditions, and b) accurate calibration data for palaeoecological proxies that enable quantification of growing season dynamics and transpiration changes in retrospect. This innovative approach is applied to fossil leaves preserved in peats and lakes from key-periods of rapid climate change: the termination of the last ice-age ~15000 years ago and the transition from the medieval climate optimum to the little ice age of the last Millennium. I will utilize the generated time-series data on growing season and transpiration data to quantify the coupling of seasonal dynamics to the global hydrological cycle.

The palaeophysiological studies provide innovative spatial and temporal information on vegetation phenology and enables more accurate estimation of its effects on Earth's carbon and water budget through time.

 

Professor Friederike Wagner-Cremer is based at the Departement of Physical Geography, Utrecht University, the Netherlands. Friederike is chair of the research group Palaeophysiology of plants in the context of environmental change.

 

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