PhD projects @TheFosterlab

This year we are advertising two PhD projects via our @NERC DTP SPITFIRE (http://www.spitfire.ac.uk/).  These studentships are fully funded, but funding is allocated on a competitive basis (based on interview and application pack).  See links below for details how to apply.

Project 1 – The Role of CO2 in the first ice ages: insights from very high-resolution boron isotope records.

The ice core records of CO2 only stretch back 800 kyr.  To find out how CO2 and climate are related before this we need to rely on indirect proxy methods – here we will apply the boron isotope proxy.  By examining the first big glacial intervals following the intensification of northern hemisphere glaciation 2.7 million years ago, this project aims to address the following questions:

·         Does the sensitivity of the climate system vary as background climate state changes?

·         What is the magnitude of CO2 variability in the early Quaternary on orbital timescales? And how does this constrain the mechanisms responsible for orbital changes in CO2?

·         What are the phase relationships between the major components of the climate system in the early Quaternary? What does this reveal about how the Earth System functions when warmer and colder than today? 

High-resolution SST records from the last glacial cycle and the target interval for this project (Marine-isotope stage 100).  Taken from Shakun (2017). 

Project 2 - Can silicate weathering regulate atmospheric CO2 during periods of rapid climate change? Testing the negative feedback hypothesis in the geological record

Over geological timescales the silicate weathering feedback process is thought to have kept Earths climate within habitable bounds by regulating atmospheric CO2 levels.  Theory suggests that it the process of weathering of continental rocks that does this. A debate remains however regarding how much weathering is a negative feedback vs. a driver of climate change.  This project aims to characterise the link between silicate weathering and climate by applying weathering tracers (e.g. d7Li, radiogenic and stable Sr-isotopes) to examining the response of weathering to rapid warming events in the past. 

Rachael goes to BATS

In October 2017 while on placement at Bermuda’s Institute for Ocean Science (BIOS) PhD student Rachael Shuttleworth had the amazing opportunity to take part in one of the monthly Bermuda Atlantic Time Series (BATS) cruises on board R/V Atlantic Explorer. The BATS cruises have taken place pretty much every month since they began in 1988, where they take monthly measurements of hydrographic and biogeochemical parameters through the water column at sites within the Sargasso Sea. This time series is an invaluable climate dataset which helps us tackle big-picture questions and better understand global climate change and the oceans’ response to this.

Rachael tells us about it:

When at sea the scientists and crew work shifts around the clock and it is impossible to keep up with all the different projects that are going on! The first job was to locate and recover lost glider “Jack” who had lost a wing, and suffered a shark attack!

Searching from the bridge for glider Jack

Leaving BIOS

Once Jack was safely on board we set off for the BATS sample site where the sediment traps were deployed. We waved goodbye to these for the week and began on the first (of many) CTD casts. The BATS team collect samples from the CTD’s for a wide range of analyses including nutrient levels, alkalinity, oxygen content, salinity, (the list goes on…!). I however was collecting samples to characterise the carbon and oxygen isotopic composition (d13C and d18O) of the water column. The water sampling came to be my favourite job on the cruise as all the scientists get together and it’s a great time to catch up with everyone!

CTD as it enters the water and begins its’ descent to 5500m!

Deploying a zooplankton tow

While the weather was still calm we were able to do a couple of zooplankton tows, however the winds soon picked up and conditions got so rough that all science was called off for the next day at least. I was secretly grateful for this, since I’d had little sleep over the previous 2 days, however my stomach was less grateful…

Sediment traps

Things had calmed down by Wednesday evening and we were able to get back to work (which consisted of many, many more CTD casts, plankton tows, radiance measurements, and collection of the sediment traps). We returned back to BIOS late Friday evening with boxes upon boxes of samples to be run – writing this a week later I don’t feel I’ve even began to scratch the surface of mine…

Science Week 2017 @ Oakwood Primary School

On Tuesday 4th July Hannah and Rachael visited Oakwood Primary School as part of their Science Week to give an assembly to our youngest climate scientists yet – Key Stage 1 (4-7 year olds)! We have made our presentation (here) available to the public, so please feel free to use it as you wish.

Hannah Donald and Rachael Shuttleworth visit Oakwood Primary School

It is so important that the key causes of the global issue that is climate change is taught in Primary Schools, as these children are part of the generation who will be living with the consequences, and finding solutions to it! The assembly took the children through a journey from learning about the fundamentals of the ‘greenhouse effect’ and how greenhouse gases have affected Earth’s climate through geological time. We then played a great game of “natural vs. man-made”, in which we introduced where greenhouse gas emissions come from, and discussed concepts such as deforestation, how our diet affects global emissions, and made the key link between electricity use and emissions. It is also important to highlight that it is not all doom and gloom, and that by working together, we can help to combat climate change! There are many tiny things that everyone (even 4 year olds!) can do every day such as switching off lights, recycling as much as possible, and opting to walk, cycle, or use public transport as much as possible.

The National Oceanography Centre in Southampton runs a scheme called ‘Eco-Schools’ which is aimed at Junior (KS2) Schools in Hampshire. This consists of a day-long visit to NOC and includes an introduction to climate change, a visit to the NOCS aquarium and several carbon footprint activities. The Foster Lab has maintained a strong tradition for STEM outreach involvement, with Hannah and Rachael helping to organise these award-winning Eco-Schools events since 2013 (more info here)

Hannah and Rachael are also STEM (science, technology, engineering and maths) ambassadors. The STEM Network (https://www.stem.org.uk/) is another fantastic way for schools to access local scientists and engineers who are enthusiastic and knowledgeable role models to inspire young people into the world of STEM. We encourage scientists and schools alike to get involved!

ALK vs. DIC

A really useful way of visualising the relationship between different aspects of the ocean carbonate system is through plots of alkalinity (ALK) vs. dissolved inorganic carbon (DIC).  For instance, the one below made by James Rae clearly shows that pH and CO2 are tightly related - as DIC or ALK (or both) change pH and CO2 change similarly.  It is this relationship that largely underpins the utility of the boron isotope pH proxy (see here for e.g.). 

ALK vs. DIC from Foster and Rae (2016; 10.1146/annurev-earth-060115-012226

I tend to use the R for making plots and analysing data these days and normally if there is something you don't know how to do you can just google it and someone would have uploaded some script somewhere.  But after many hours of searching i couldn't find something to make plots like these, so had to make my own using the seacarb package.  I have uploaded it here with some annotations so you can make one if you like.  I dont think mine is as pretty as James' but its not bad for a first attempt -  Let me know if you make it better! 

My trip to New Zealand

Post By: Rachael Shuttleworth

What drives glacial – interglacial CO2 level changes is what is known as the “holy grail” of palaoceanography. Though the question as to whether these changes are caused by biologically or circulation dominated process is still hotly debated. To better quantify and enhance our understanding of the processes and mechanisms which control CO2 on these timescales we must look to the past for answers. This is the focus of my PhD @thefosterlab and we are initially targeting cores taken from variety of latitudes in the southern Pacific Ocean, ranging from subtropical to polar waters. These cores are stored at NIWA in Wellington, New Zealand – someone had to do the tough job of collecting the samples...

In order to get the data we want, a lot of preparatory work on the samples has to be undertaken. Firstly we must sample to core itself, taking slices of mud at specific depths which correspond to the time periods of interest.

These cores are then put into an oven overnight to dry out.

These dried samples are then washed over a 63micrometer serve to remove the very fine mud particles. They are then put back into the oven to dry again.

The information that we want is stored in foraminifera within these sediments, and so the next step is to pick these micro fossils out one by one.

These samples are now prepped and will be sent back to @thefosterlab based at the National Oceanography Centre, Southampton where analysis on their isotopes will be undertaken. Many of these cores already have carbon, oxygen and nitrogen isotope records which can tell us about temperature, age, ice volume, and productivity. For my PhD I will focus on obtaining a boron isotope record which will tell us about the change in flux of CO2 into the oceans from the present day back to the last glacial maximum. By comparing this with dust flux and productivity records I hope to better quantify the role that relaxation of micronutrient (such as iron) limitation due to enhanced dust deposition played during the last glaciation. This will provide further insight into how much biology played a part in driving glacial-interglacial CO2 change, as well as the potential carbon storage via this mechanism of iron fertilisation.

Its still early days for my PhD, and I now have my first sample set.  Next stop – the lab!

Future relevant climate sensitivity (part deux)

A paper out this week by Friedrich et al. (2016) is the latest in what seems like a series this year determining climate sensitivity using the palaeoclimate record (see here).  This is a very powerful approach but has its difficulties many of which are discussed in our previous post and here.  The Friedrich et al (2016) study used a new empirical estimate of Surface Air Temperature (SAT) based on a compilation of Sea Surface Temperatures (as did Snyder recently) and a complete assessment of the processes “forcing” climate change over the last ~800 thousand years (e.g. CO2, land-ice albedo, and dust) to identify that climate sensitivity changed as a function of climate state: they found it was ~1.8 K per CO2 doubling when the Earth was substantially colder than today and ~5K per doubling when the Earth was only a little bit colder than the pre-industrial.  We @theFosterlab were just involved in a review on this subject (here) and a summary of the literature from that paper is shown below.  

Friedrich et al. go further than other studies and apply the palaeo-sensitivity to predict our warm future (see figure below).  They correct for the fact that over the next 100 years the climate isn’t in equilibrium with its forcing and show that the high “warmer-paleo” sensitivity yields temperature in 2100 AD, given a business as usual RCP8.5 emissions scenario, that could be as high as 6 K (5-7 K) compared to 5 K (3 -6 K) from the CMIP5 models (see figure below). 

The accuracy of such a paleo-sensitivity approach to predict the future climate is: (i) very dependent the accuracy of the temperature record used to determine sensitivity in the past (and others limitations, see http://julesandjames.blogspot.co.uk/); (ii) but is reliant on the assumption that the sensitivity estimated from climates slightly warmer and substantially cooler than today is applicable to Earth temperatures up to 5 K warmer.

I think it’s a great finding of this paper that climate sensitivity is state dependent over the Pleistocene glacial cycles, but this also means it’s probably an over simplification to assume that a similar state dependency doesn’t characterise the system when temperatures are substantially higher than the pre-industrial (see top figure). 

We attempted to investigate this in this paper in 2015 using boron isotope based CO2 data from the Pliocene.  We didn’t examine the data for a state dependency within the Pliocene (see here for why) but determined that the average climate sensitivity in the Pliocene was ~3.7 K per CO2 doubling (with an uncertainty of 2-6 K).  This overlaps with what Friedrich et al. determine as “warm-paleo” sensitivity.  However, my feeling is that, given the current uncertainties in determining climate sensitivity in the past, rather than indicating the Earth system is more sensitive than the future, studies like that of Friedrich et al. (2016) and our own (http://www.nature.com/nature/journal/v518/n7537/full/nature14145.html) are very important validators of our understanding of the behaviour of the climate system encapsulated by the CMIP5 models.  These are very different ways to understand the climate system yet they give the same results – this is very powerful and is a great illustration of the utility of palaeoclimate research.  As a community we now need to work hard to reduce the inherent uncertainties and get the most out of the rock record of past climate changes.

PhD opportunities with @theFosterlab

This year we are offering the following PhD projects:

The temperature control on the strength of the biological pump as revealed by palaeo-pH depth profiles

How does the silicate weathering feedback work? Insights from super-high precision 87Sr/86Sr measurements in past greenhouse climates

Climate feedbacks and Earth's habitability

What controls the pH of the microenvironments around foraminifera and what does this mean for records of past ocean chemistry

A multidisciplinary investigation into how the port of Southampton contributes to air pollution in the city

These projects are fully funded but appointment will be through a competitive process.  Deadline for applications is 4th Jan and see here for details on how to apply

http://noc.ac.uk/gsnocs/how-apply

Contact Gavin for more information.

Future Relevant Earth System Sensitivity

A recent paper by Carolyn Snyder published in Nature this week presented a record of global average surface temperature (GAST) reconstructed from a compilation of sea surface temperature records.  This is a great approach and the GAST record, and the techniques used, will be very valuable in efforts to use the geological past to understand how the climate system works.

However, towards the end of the abstract, and the focus of the press release, was a statement about Earth System Sensitivity (the temperature change in response to CO2 change – subtly different to equilibrium climate sensitivity – see here for detail).  Earth system sensitivity, unlike equilibrium climate sensitivity, includes the action of all climate feedbacks (except those relating to the carbon cycle) and is very dependent on the background climate state.  Synder calculated that ESS was around 9 oC per CO2 doubling over the last 800 thousand years.  As discussed here, this is not a relevant measure of how our future climate system will behave because the high ESS during the cold Pleistocene was driven in part by the changes in surface albedo caused by the waxing and waning of the continental ice sheets of North America and Europe – ice sheets that are no longer present on the Earth so are not able to act as a feedback in the future.  ESS for the future is therefore much lower than what Synder calculates.  In a paper last year we @thefosterlab used new Pliocene CO2 data from the boron isotope proxy to show that a future relevant ESS is more likely in the range 2.2 to 5.2 oC per CO2 doubling (which is in good agreement with modelling studies; Lunt et al. 2010).  This suggests that estimates of equilibrium climate sensitivity from the IPCC (1.5 to 4.5 oC per CO2 doubling) do adequately describe the long-term (1000 year) response of the future climate system to CO2 change because the northern hemisphere ice sheets are currently at close to their minimum extent.

The figure above is from Martinez-Boti et al. (2015) showing the Sensitivity Parameter for the Pleistocene (red) and Pliocene (blue) for two different temperature records - mean surface air temperature (left) and sea surface temperature (right).  The Sensitivity Parameter describes the temperature change for a given change in climate forcing.  Panels (a) and (c) show the sensitivity parameter due to CO2 change only.  ESS = this sensitivty parameter multiplied by 3.7 (the radiative forcing from a doubling of CO2).  ECS is approximately the senstivity parameter in panels e and g multipled by 3.7 (because here we also take into account the radiative effect of the ice sheets).  As in the Synder paper we also found a high ESS for the Pleistocene because of the large ice sheets present (ca. 2 x 3.7 = 7.4 oC per CO2 doubling).  The Pliocene however lacked large ice sheets and ESS is about equal to ECS, which both fall in the IPCC range (ca. 1 x 3.7 = 3.7 oC per CO2 doubling).

2016: the first year of 400 ppm? The Foster Lab interviewed on BBC Radio Weather Show

A paper published this week by Richard Betts of the UK Met Office predicted that 2016 will be the first year CO2 will be >400 ppm at the Mauna Loa observatory all year round.  Given the 2-3 ppm yearly increase this signals that CO2 is likely to remain >400 ppm for our lifetime.  This was featured by the BBC website that also included reference to the work fo the Foster Lab and one of our earlier blog posts.  On Wednesday this week Gavin was also interviewed for the Paul Hudson Weather Show about the last time CO2 was 400 ppm.  The show was broadcast this morning at 6am (18/6/16) on BBC Radio Humberside and will be broadcast on BBC Radio Lincolnshire on monday (20/6/16).  You can also listen to the entire show here:

http://www.bbc.co.uk/programmes/p03xfgx6#play

or fast forward to 32 mins to hear Gavin!

The question is now not if we are heading for a Pliocene-like future, but how long will it take to get there...

Vacancies @theFosterlab and in the Geochemistry Group

We have two vancancies we are looking to fill, click the links below for more info and details on how to apply:

A permanent Geochemistry Technician to support the activities that go on in the Foster Lab and in other research areas atSouthampton

A 3 year Research Fellow position to look at boron isotopes in corals

Ancient marine sediments provide clues to future climate change

Fossil planktonic foraminifera (33-50 million years old) from Tanzania by Paul Pearson, Cardiff University is licensed under a Creative Commons Attribution 4.0 International License

A paper led by the fosterlab’s Dr. Eleni Anagnostou and featuring Prof. Gavin Foster is published today in Nature (here). It represents the latest in our efforts to use the geological record to provide information about how the Earth’s climate system operates when significantly warmer than today (e.g. see here).  It was work funded as part of the “descent into the icehouse” project that involved researchers from a number of UK universities, and is part of the NERC life and planet theme.

Here is the press release from the University of Southampton.  And here is a short video that discusses the wider project:

Our principle finding in this new paper is that atmospheric CO2 was around 1400 ppm during the warmest part of the Eocene and approximately halved through the Eocene.  We determined this by using boron isotopes.

Last year Dr. Gordon Inglis from Bristol who is also involved in this work published this paper that better demonstrated that: (a) the early Eocene (~53 million years ago) was warm (the best estimates, here, are at +14 oC compared to the pre-industrial); (b) there was around 8 oC of cooling for the high latitude surface ocean and around 2 oC of low latitude cooling through the Eocene (from ~53 to ~34 million years ago).

We know from earlier work that some of the warmth of the Early Eocene was caused by changes in the position of the continents, vegetation change, and the lack of any ice sheets on the South or North poles.  This leaves around 9 oC of the early Eocene warmth to be explained.  CO2 is a potent greenhouse gas (see here for example; ) and when its concentration is doubled in the atmosphere (www.ipcc.ch) the Earth should warm by 1.5 to 4.5 oC.  Levels of CO2 of 1400 ppm is ~5 times the pre-industrial concentration of atmospheric CO2. This means, if the Earth’s climate system really behaves like we think, the early Eocene should be between 4 and 11 oC warmer than the pre-industrial (when CO2 was 280 ppm).  The 9 oC warmth of the early Eocene is thus entirely explained by the enhanced greenhouse effect due to the higher CO2 at the time. This finding also supports our earlier work that suggests the sensitivity of the climate system to forcing from CO2 doesn’t depend hugely on climate state. 

We also know from previous work that surface temperature in high latitude regions tend to change more than the global mean, and low latitude regions tend to exhibit a more muted change than the mean.  Given the nature of this “polar amplification”, we further demonstrated in this new paper that the CO2 drop through the Eocene (from 53 to 34 million years ago) was sufficient to drive the observed (2 oC low latitude and 8 oC high latitude) cooling in sea surface temperature.

These two findings (that CO2 drove much of the warmth of the Eocene, and its decline drove much of the cooling through the Eocene) confirm that not only are the IPCC estimates of climate sensitivity consistent with the geological record, but that CO2 change was a major player in driving the switch between the Cretaceous/early Cenozoic greenhouse climate state to the late Cenozoic ice house climate we currently find ourselves.   The next question of course, and one we are working on, is why did CO2 decline through the Eocene? A recent paper in Science by MacKenzie et al. suggest it’s all about volcanoes and their emissions of CO2. Whatever the cause, its only with CO2 records like we present here we will be able to provide a deeper understanding of the role of CO2 in natural and anthropogenic climate change.

The Earth in a bottle - CO2 games on my kitchen bench

UPDATE 02/09/2016: it has come to my attention (thanks Katharine Hayhoe) that the experiment below was first performed by Mrs. Eunice Foote and reported to the American Association of Science in 1856! here is the report (thanks Gavin Schmidt for the link).  She even foretold the future "An atmospheric of [carbonic acid gas - CO2] would give our earth a high temperature...".

John Tyndall was perhaps the first scientist to recognise the radiative properties of CO2 in 1859. In recent years the study of the role of CO2 and global warming has moved beyond the physics of CO2 and more frequently we hear discussions of record breaking temperatures or equilibrium climate sensitivity in state of the art computer models.  I think it’s quite refreshing though to go back to basics and remember that the theory of global warming is: 1. Over 150 years old; 2. rooted in simple physics (CO2 present in the atmosphere  absorbs long-wave radiation that it later releases warming the air a bit). 

There are quite a few experiments that you can do at home to demonstrate this underlying physics (e.g. here). Over the last couple of weeks I’ve been gathering the necessary equipment to do one of these simple experiments and this weekend I thought I’d give it go.

Here is a picture of my “experimental set-up” on my kitchen bench

It consisted of two Infrared heat lamps (200W), two plastic drinks bottles, to silicone rubber stoppers, two digital fridge thermometers (with some play-doh to seal the hole in the stoppers),  and the all-important CO2 in a can.   

I filled one of the bottles with CO2 (the one on the left in the picture of above) and turned on the lamps.   Entirely consistent with our understanding of the physical properties of CO2, the extra CO2 in this bottle absorbed more of the infrared radiation from the lamp and subsequently released it warming the bottle more than the one with just air in it.

It doesn’t take someone with a Nobel prize to draw parallels between what is happening in this bottle and what is currently happening to the Earth! So remember: the theory of global warming is quite simple and the question should not be “are we warming?” but “how hot is it going to get?”

Decent into the Icehouse Teaser Trailer

Heres a short video introducing a recent project from The Foster Lab that is shortly coming to an end.  Tune in soon to find out more and take a look at some of our recent publictions for some of the latest results:

Lunt, D.J., Farnsworth, A., Loptson, C., Foster, G.L., Markwick, P., O'Brien, C.L., Pancost, R.D., Robinson, S.A., Wrobel, N. (2015) Palaeogeographic controls on climate and proxy interpretation Climate of the Past Discussion 11, 5683-5725,  doi:10.5194/cpd-11-5683-2015

Inglis, Gordon N., Farnsworth, Alexander, Lunt, Daniel, Foster, Gavin L., Hollis, Christopher J., Pagani, Mark, Jardine, Phillip E., Pearson, Paul N., Markwick, Paul, Galsworthy, Amanda M. J., Raynham, Lauren, Taylor, Kyle. W. R. and Pancost, Richard D. (2015) Descent toward the Icehouse: Eocene sea surface cooling inferred from GDGT distributions. Paleoceanography, Early View (doi:10.1002/2014PA002723). click here for data.

Data and R-script for plotting 400 ppm figure

I've had a few requests for the data used to plot 3 million years worth of CO2 in the 11 Nov Blog Post below.  Here are the data files and here is the R-script i used to make the plot.  By the way, because im lazy i used Corel to add labels - sorry! Good luck and be sure to share your efforts!

Is this the last year below 400 ppm?

The average CO2 value for October 2015 was 398.29 ppm.  Ralph Keeling (and he should know) thinks this month (November) may be the last time that CO2 will be below 400 ppm again in his life time (or for that matter, anyone’s lifetime).  His post here discusses why he thinks this is.

CO2 compilation from ice core (in red; Bereiter et al., 2015, GRL, doi: 10.1002/2014GL061957) and boron isotopes in blue (Hoenisch et al., 2009, Science,  doi: 10.1126/science.1171477 and Martinez-Boti et al., 2015, Nature, doi:10.1038/nature14145)

400 ppm is of course only a symbolic threshold but as the guys at Mountain Beltway suggest it should give us reason to pause and contemplate what a momentous change it is in terms of the planet.  Something we do in thefosterlab is reconstruct CO2 in the geological past using the boron isotope proxy and this allows a little bit more perspective on this issue.  The image above is a plot compiling the state of the art when it comes to CO2 over the last 3 million years or so, including some data for the Pliocene (2.6 to 5.3 Million years ago that we published this year in Nature).  What is clear is that the last time CO2 was 400 ppm was around 2.5 to 3 million years ago.  The world was a different place back then – global temperatures around 3 C warmer than the pre-industrial and sea-levels were around 20 m higher (due to retreat/collapse of the West Antarctic and Greenland ice sheets).  With global temperatures likely to top 1 C above pre-industrial levels this year and CO2 now likely to stay above 400 pppm it appears we are well on the way to a Pliocene-like future.     

Fully Funded PhD's

Want to do a PhD with us? We have a number of projects this year to chose from: 

Dust and the causes of glacial-interglacial CO2 change

The role of CO2 in the intensification of Northern Hemisphere Glaciation

Reconstructing historic sea surface temperature using corals from Belize

Impact of Ocean Acidification on skeletal strength of corals and coralline algae

Mapping and geochemistry of deep sea-coral from the Mediterranean

Climate sensitivity to greenhouse gas forcing using a new model

Boron isotopes tracing igneous processes during collisional tectonics

Reconstructing the change in ocean circulation across the last great climate transition (the intensification of northern hemisphere glaciation)

All the projects will be based at Southampton and see the GSNOCS website for more details.  Contact Gavin if you need more information