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

Past to Future Climate Change

Background:

Since the industrial revolution the concentration of atmospheric CO2 and other greenhouse gasses have increased. This has already caused demonstrable climate change.  Important insights into exactly how the climate will change in the future in response to increased greenhouse emissions can be gained from looking into the past to those time periods where the climate state was different to today (article). For instance, we in the Geochemistry Group have already shown that by combining geological evidence with numerical models of the climate system we can dramatically reduce the uncertainties in not only how sensitive the climate system is, but what this means for required carbon budgets to limit future warming to <2 oC (article).

Key Questions:

1. What is the sensitivity of the climate system to CO2 forcing? - is it, as some of our recent work suggests, dependent on background climate state (article)? Are there tipping points in the climate system that will lead to rapid and dramatic climate change?

2. What is the relationship between CO2, ice-volume and sea level? - how high will sea level rise as the major ice sheets melt in the future?

3. What processes drive natural CO2 variability? - why and how did climate and CO2 change in the past?

4. How can we improve the methods of reconstructing past climate? - can new technologies be leveraged to improve our reconstructions of past environmental change?

5. How can our reconstructions of the past be used to better predict the future? - is the understanding of the climate system encapsulated in cutting edge climate models correct?

Clean Lab Suite
The Geochemistry Group has an extensive suite of clean laboratories.
Eocene planktonic foraminifera
Eocene planktonic foraminifera (image credit: Paul Pearson)

How do we do it?

In the Geochemistry Group we use cutting edge analytical techniques (see Facilities page) to measure the chemical (e.g. Mg/Ca, B/Ca, Li/Mg) and isotopic composition (e.g. δ2H, δ13C, δ11B) of ancient organisms (e.g. microbes, foraminifera, corals). 

From the chemical and isotopic signals locked up in ancient organisms we can reconstruct ocean pH (and hence atmospheric CO2), ice volume (and hence sea-level) and water temperature (and hence global climate). Samples are frequently retrieved by ocean and continental drilling via the IODP and ICDP.

These reconstructions can be combined to estimate important parameters of the ancient climate system (such as the climate sensitivity), testing and refining the outputs of climate models used to predict the future and feeding into international efforts like the Intergovernmental Panel on Climate Change (IPCC). 

Figure 1. Past climates over the last 60 million years provide context for our future climate scenarios (from Tierney et al. 2020; Science https://doi.org/10.1126/science.aay3701.

Figure 2. The reconstructed sea-surface temperature anomaly for the Pliocene Warm Period (from Dowsett and Robinson, 2008 doi:10.1098/rsta.2008.0206)

Past climates
Figure 1. Past Climates
Sea-surface temperature anomaly
Figure 2. Reconstructed sea-surface temperature anomaly

 

 

 

 

 

 

 

 

 

Who in the Geochemistry Group is involved?

Prof Gavin Foster; Dr Jessica Whiteside; Dr Gordon Inglis; Prof Martin Palmer.

Links to other Research Themes

What does a 3 to 5º warmer world look like?

How fast does climate change?

Carbon Dioxide Removal and Storage

 

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