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The University of Southampton
Ocean and Earth Science, National Oceanography Centre Southampton

How fast does climate change?

Coring deep sea sediments off NW Africa
Coring deep sea sediments off NW Africa. Image credit: Steve Bohaty

Background:

Locked in the physical, chemical and biological composition of successive layers of sea floor- and lake bed- sediments, are long undisturbed records of environmental change. Fundamental to deciphering these records is the non-trivial challenge of converting layer-depth into layer-age to determine the stratigraphy or chronology of events. We use cutting edge chronostratigraphic methods to develop the robust, high-precision age models needed to determine rates and cause of environmental change.   

Key Questions:

1. How does Earth's climate respond to astronomical forcing in different climate states? How stable are different climate states and how fast are the transitions between them?

2. How do the annual seasonal cycle and inter-annual and decadal modes of climate variability respond to millennial, astronomical and greenhouse gas change? Can we untangle the anthropogenic signal from natural variability in climate records of the last three hundred years?

3. What causes the strength and direction of Earth’s magnetic field to change? Can we determine change in field intensity sufficiently precisely to use it, alongside field reversal events, to understand the Earth’s geodynamo and make a step-change in stratigraphy?

How do we do it?

We are studying cores taken from thick deposits in lakes and oceans where the sediment layers were deposited at unusually high rates (e.g., Hernandez-Molina 2014; Spray et al., 2019; Nichols et al., 2020). We are working with laminated sediments and corals to study seasonal to decadal variability over centuries to millennia (e.g., Avery et al., 2019).

And we have composited data sets together to build an astronomically dated record of Earth’s climate and its predictability over the last 66 million years (Westerhold et al., 2020).

Who in Palaeoceanography and Palaeoclimate is involved?

Steve Bohaty; Alan Kemp; Paul A. Wilson; Chuang Xuan.

Links to other Research Themes

Global overturning circulation

Past to Future Climate Change

IODP - Exploring the Earth Under the Sea

Landscape Dynamics and Ecology (LDE)

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Students processing sediment cores on deck stationed off the rapidly retreating Pine Island Glacier, Antarctica. Credit, Becky Hopkins.
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Desert expansion in action on the Arabian Peninsula. Credit, Anya Crocker.
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Discovering the chronology of Antarctic climate in the Ross Sea. Credit, Heather Barnes, IODP.
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R/V JOIDES Resolution comes into port in southern Chile as one of our team completes his expedition and another prepares to start her's. Credit, Anieke Brombacher
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