Half-term assessment

Friday 11 June 2021 15.00 – 16.00


Petter Hällberg will present his half-term assessment on June 11th at 15h00 via zoom.


Biomarker paleoclimate proxies and modelling

Zoom link: https://stockholmuniversity.zoom.us/j/9904967069

river, foggy and dusk ligth

The Indo-Pacific Warm Pool (IPWP), termed the ‘steam and heat engine of the world’ is a major driver of global climate variations on annual to millennial time scales. Its substantial area of permanently >28 °C warm sea-surface-temperatures plays a key role by altering the heat and moisture distribution around the tropics via El Niño Southern Oscillation (ENSO) and the circumtropical Walker Circulation and to higher latitudes through the summer monsoon systems.

Observations show an accelerated expansion of the IPWP in recent decades due to a combination of natural and anthropogenic forcing. While a further expansion of the IPWP area is expected due to global warming, there is still a quite limited understanding of the region’s sensitivity to external forcing and how IPWP changes in return will impact the regional to global climate including major monsoon systems. It is thus crucial to study and reconstruct past climate states from proxy and modelling perspectives to gain more confident assessments of climate projections.

Most paleoclimate information to date comes from marine sediments recording sea surface temperature, combined with cave speleothem oxygen isotope records as proxy for past hydroclimate. However, hardly anything is known about past land temperatures. Notably, not a single terrestrial high-resolution temperature reconstruction is available from tropical South East Asia according to Holocene paleoclimate databases. Past seasonality of temperature and precipitation are also poorly resolved. Recent advances in organic geochemistry now allows reconstruction of past terrestrial temperature and hydroclimate, opening the door for a greater understanding of tropical climate dynamics, and the interplay between atmospheric circulation, temperature and precipitation. High resolution modelling can then further be used to understand climate variability on monthly or seasonal time scales and to evaluate spatiotemporal patterns of climate change relative to proxy-studies.

In the proposed PhD project, we investigate the seasonality of precipitation and temperature via climate modelling, and reconstruct terrestrial paleoclimate via organic geochemical analyses of peat deposits, with a focus on lipid biomarkers and their stable isotopic composition.

Zoom link: https://stockholmuniversity.zoom.us/j/9904967069