UCL Department of Geography
Dr Chris Brierley
  
UCL Home ›› Department of Geography ›› About the Department ›› People ›› Academic Staff ›› Chris Brierley
Personal tools
Log in

Dr Chris Brierley

Contact

1.jpgDepartment of Geography

University College London
Pearson Building
Gower Street
London
WC1E 6BT

E-Mail: c.brierley@ucl.ac.uk
Tel.: +44 (0)20 7679 0571

OrCID: 0000-0002-9195-6731

ResearcherID: A-8417-2009
Google Scholar

 

Biography

I am interested in the role of the ocean under climate change. I use climate models to uncover this role both in the geologic past and the future. I joined UCL from Yale, where I worked closely Alexey Fedorov on the Pliocene climate. Prior to that I researched ocean model uncertainty and its impact on climate projections during my PhD at Reading University.

I discovered that the meridional (North-South) extent of warm tropical waters was much larger in warm past climates, and have looked at the consequences of this for the climate of past 5 million years (more). It has been suggested that tropical cyclones (e.g. hurricanes) play an important role in the climate system and we have discovered a climate feedback involving them, which may explain permanent El Niño (more). I have published several articles looking at the contribution of uncertainties in ocean model parameter values to the total uncertainty of climate projections (more). You can find out much more about these topics and more on myresearch page.

I have been involved in publishing a quick guide to climate change with Pocket Issue. If you have specific questions about climate change, I also recommend that you look at the results of the NERC climate change challenge and the summary that I compiled about it.

I am in charge of both the MSc in Climate Change and the MSc in Environmental Modelling.

Publications

Selected Publications

Fedorov, Brierley, Lawrence, Liu, Dekens, and Ravelo (2013), Patterns and mechanisms of early Pliocene warmth, Nature, 496(7443), 43–49, doi:10.1038/nature12003.

Brierley, Fedorov, Lui, Herbert, Lawrence, and LaRiviere (2009), Greatly Expanded Tropical Warm Pool and Weakened Hadley Circulation in the Early Pliocene, Science, 323(5922), 1714–1718, doi:10.1126/science.1167625.

Fedorov, Brierley and Emanuel (2010), Tropical cyclones and permanent El Nino in the early Pliocene epoch, Nature, 463(7284), 1066–1070, doi:10.1038/nature08831.

Brierley, Collins and Thorpe (2010), The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model, Climate Dynam., 34(2-3), 325–343, doi:10.1007/s00382-008-0486-3.

Click here for my full list of Publications

AGU Fall Meeting, December 2013 - "Pliocene climate: fleeting past or a blueprint for the future", GC53C-03, Contribution to the session Understanding 400 ppm Climate: Past, Present and Future.
The role of oceans in climate uncertainty, BIRS workshop, Banff, CA, October 2013 - "Could slab model emulation be a useful tool in ocean uncertainty quantification?"

2nd workshop on Pliocene climate, Bristol, September 2013 - "Patterns of early Pliocene warmth: testing potential mechanisms"
4th WGNE workshop on systematic errors in weather and climate models, Met. Office, April 2013. "Simple measures of structural climate change" WGNE_2013_poster_thumbnail
University of East Anglia, School of Environmental Sciences, November 2012 - "Measurement and mechanisms of a structural climate change in the Early Pliocene" - in the Atmosphere, Ocean and Climate Seminar Series
University of Nottingham, Geography, November 2012 - "Structural climate change and the Early Pliocene" - Physical Geography Seminars
London Palaeoclimate Group, November 2012 - "An Introduction to PMIP3"
University of Edinburgh, School of GeoSciences, November 2012 - "Lessons from the warm Early Pliocene" - in the Global Change Seminar Series
Imperial College London, Physics, October 2012 - "Structural Climate Change" - in the Space & Atmosphere Physics Seminar Series.

EGU Spring Meeting, April 2012 - "Can inter-ocean gateways explain long-term cooling since the early Pliocene?", EGU2012-5484, Poster in Session CL4.2/OS1.3

Also presented at Palaeoclimate Modelling Intercomparison Project, Phase 3 Workshop at Crewe, May 2012

EGU_Gateways_Poster_Thumb

University of Bristol, Geography, April 2012 - "Equatorial Temperature Gradients and Human Evolution"

Also presented as subsidiary talk at Brown University, March 2012

Brown University, Geological Sciences, March 2012 - "Beyond conventional climate sensitivity: understanding early Pliocene warmth"

Also presented at University of Exeter, College of Engineering, Mathematics and Physical Sciences, May 2012, in a modified form.

University College London, Geography, November 2011 - "Ice Age Tropical Cyclones" - in the Physical Geography Seminar Series
University of Massachusetts, Amherst, Geosciences, June 2011 - "Comparing hypotheses for Pliocene tropical warmth"
University of Southern California, Earth Sciences, April 2011 - "Better climate predictions using hindsight"
AGU Fall Meeting, December 2010 - "The relative role of temperature gradients in the Pliocene climate", PP11G-03, Invited contribution to the session The Early Pliocene Warm Period as an Analog for Future Warmth.
AGU Fall Meeting, December 2010 - "Tropical Cyclones at the Last Glacial Maximum" Poster in session GC51G AGU2010.GC51G-0813.thumb.jpg
Luncheon with the Postdocs, Yale Geology & Geophysics, April 2010 - "Vertical Mixing and the Ocean Circulation"
Ocean Sciences, 2010 - "Extratropical Hurricane Mixing and the Equatorial Cold Tongue", PO45W-04 in the session Theory and Modeling of the Equatorial Ocean. Also presented at the Department of Energy meeting in Gaithersburg in April 2010. OceanSciences.poster_thumb.jpg
AGU Fall Meeting, 2009 - "Understanding Weak Low-Latitude SST Gradients and the Ocean Warm Pool Expansion in the Early Pliocene", PP11G-08 in the session The heat is on: past, present and future climate change in the Indo-Pacific warm pool.
University of Michigan Geological Sciences, Seminar, November 2009 - "Tropical Cyclones and the climate of the Pliocene"
Ocean-Atmosphere Energy Transport workshop, Caltech, November 2009 - "Extratropical Mixing, Ocean Temperatures and Heat Transport". Poster Caltech.poster_thumb.jpg
Graduate School of Oceanography at University of Rhode Island, Invited Seminar, July 2009 - "Implications of the Vast Pliocene Warmpool"
Yale's Atmosphere, Ocean and Climate Dynamics group, March 2009 - "Temperature Gradients and Glaciation"
Yale's Atmosphere, Ocean and Climate Dynamics group, October 2008 - "The Curious Case of the Pliocene Climate"
Pliocene Model Intercomparison Workshop, June 2008 - "Greatly Expanded Warmpool and the onset of Glacial Cycles". Poster
PlioMIP_Poster_2008.jpg
Pliocene Model Intercomparison Workshop, June 2008 - "Greatly expanded warmpool, permanent El Nino and weaker Hadley circulation in the early Pliocene". Oral presentation given on behalf of Alexey Fedorov
AGU Fall Meeting December 2007 - "Permanent El Nino Conditions and the Meridional Expansion of the Tropical Ocean Warm-Water Pool in the Early Pliocene: Modeling Global Impacts with an Atmospheric GCM". Poster: PP43C-1531 AGU_fm07_poster_thumb.jpg
Luncheon with the Postdocs, 2007 - "Ensembles, Uncertainty and Climate Projections"
Departmental Seminar, Uni. of Reading, June 2006. "Ocean Model Uncertainty"
Chapa Club 2006 - "Spatial Patterns of Climate Change in HadCM3" This presents the ensemble mean patterns from my perturbed ocean physics ensemble. The results are the average of year 61-80 from an 1% increase in carbon dioxide, so are centred on the time of CO2 doubling. It has a useful list of references for HadCM3 and climate change in it.
AGU Ocean Sciences, 2006 - "Incorporating and Quantifying Ocean Uncertainty in Ensemble Climate Prediction", OS52P-05 in the session on Ocean Convection, Heat Transport and Storage, and Climate.
Reading University's Ocean Research Group 2nd February 2006 - "The Relative Certainty of Ocean Parameters"
Royal Meteorological Society biennial conference, 2005 - "Including Ocean Model Uncertainties in Climate Predictions"
Departmental Poster Session, October 2005 - "The effect of Isopycnal Mixing in HadCM3"
isopyc_poster.jpg
Chapa Club October 2005 "Opal Fruits: made to make your mouth water"
Earth System Sciences Summer School, September 2004 - Ocean Model Uncertainty I created this early on, and it describes why ocean model uncertainty exists.
ES4_poster.JPG

Research

Early Pliocene Climate

As new data emerges, our interpretation of the early Pliocene climate continually evolves. More and more data from the last few years indicate a persistence of a significantly reduced zonal temperature gradient in the equatorial Pacific, which is associated with climate conditions usually referred to as a "permanent El Niño". We have collected together data from a variety of regions in both Pacific and Atlantic oceans to reconstruct the meridional temperature gradient in the ocean during the early Pliocene. Our results indicate a substantial reduction in the meridional temperature gradient from the equator to the subtropics (in comparison with today's climate) and a large poleward expansion of the warm-water pool in the tropical Pacific.

I have used an atmospheric general circulation model to look at the implications of a reduced meridional temperature gradient (by forcing it with hypothetical surface temperature boundary conditions, representative of our new understanding of the early Pliocene). I've explored the changes in the global circulation and precipitation patterns, along with inferences about the ocean heat transports. The Walker circulation is virtually removed by the imposed SST boundary conditions. The latitudinal extent of the Hadley cell increases only slightly, but the strength of the Hadley circulation is substantially reduced, which results in a weakening of the poleward heat transport by the atmosphere in the low- to mid- latitudes.

Previous research shows that oceans models predict a reduction in the ocean heat transport in the early Pliocene, rather than the warming my results would indicate. The issue of poleward heat transport in the early Pliocene has been called the "Pliocene Paradox".

The temporal evolution of the meridional and zonal SST gradients in the tropical Pacific differ over the past 4 million years. We have used atmosphere modelling to determine the relative effects of the zonal and meridional gradients on glacial inception. Tropical merdional SST gradients, thought to be relatively constant until our study, play a much more dominant role than zonal gradients. Therefore reproducing the correct SST patterns appears to be critical for a climate model to account for ice-sheet inception.

Hurricanes and Climate Change

Tropical cyclones (such as hurricanes and typhoons) can have disastrous human impacts. There is substantial interest in the response of tropical cyclones to climate change, and recent evidence suggests they may also affect the dynamics of the climate system. Yet some fundamental issues remain unclear. An area of substantial research is the response of tropical cyclone activity in changed climates. There has been little work performed however on the question of whether tropical cyclones influence various components of the climate system. We have used our knowledge of the early Pliocene is to investigate this issue.

It is logical that the altered SST pattern of the early Pliocene has a different spatial distribution of tropical cyclones. Our atmosphere simulations show a surface warming and a reduction of windshear (with the reduction of the Hadley Cell), both of which would act in concert to form tropical cylceones more easily. Tropical cyclones are a substantial source of upper ocean mixing and altering the spatail location of that mixing could have interesting consequences. Were the mixing to impact the ocean pathways that cold water takes before upwelling in the east equatorial Pacific, then sea surface temperatures would be expected in a region already known to have global impacts - potentially feeding back onto the tropical cyclone distribution. This work was published in Nature (http://dx.doi.org/10.1038/nature08831) and featured on the cover.

I have also looked at how hurricane mixing is parameterized in climate models. We have performed a series of simulations using various temporally different representations of intermittent mixing. We find the spatial pattern is the response is robust, although the magnitude varies somewhat. This work (http://dx.doi.org/10.1029/2011JC007295) gives credence to the previous work that used a permanent, annual average parameterization of hurricane mixing.

Ocean Parameter Uncertainty

Atmosphere-ocean general circulation models are the best tools available to provide policy-relevant predictions of the climate's response to a change in the amount of atmospheric CO2. They include parameterisations of physical processes that cannot be resolved explicitly. There is uncertainty in the numerical values (parameters) involved in the parameterisation of ocean physics. This is called ocean parameter uncertainty. My work was the first investigation of the effects of this uncertainty in a complex climate model.

I created a database of ocean parameters and their uncertainty ranges for a complex model (HadCM3) through expert consultation. A perturbed physics ensemble was then created from the highest priority parameters. The ensemble represents an upper bound of ocean parameter uncertainty. Each ensemble member has been run to a preindustrial quasi-steady state. I looked at the effects of ocean parameter uncertainty on the long-term climate state: there is surface temperature uncertainty of greater than 2.5°C at high latitudes.

I then performed a climate change experiment with CO2 increasing by 1% per year with the ensemble. The effects of ocean parameter uncertainty on the climate change signal can be detected above natural variability. The global mean effects are compared to those seen from other sources of uncertainty. I've investigated the regional patterns of the effects on the surface climate change signal: they are over 100% of the ensemble mean signal in regions of strong vertical ocean heat transfers. I have also investigated the effects on the vertical structure of the ocean.

Analysis of the evolution of ensemble spread with increasing CO2 reveals an anti-correlation between the preindustrial global mean temperature and the transient climate response. This is an interesting feature of the ensemble, because the majority of climate change studies are designed to completely remove any such dependence. The relationship is mediated by variations in ocean heat uptake processes and climate feedbacks in approximately equal measure.

Impact

Climate change is a major problem that needs to be acted upon for the future of human civilisation. My research looks at how we understand the physical climate system and how it has responded in the past and may respond in the future. Obviously knowledge of this kind is essential, but it is really just diagnosing the problem we face rather than trying to move to a solution.

I see that the biggest contribution I can make as in my personal life  is through using my expertise to educate others and raise awareness of the issue. This has led me engage with the public through a series of conventional science education activities. The most substantial of these has been a short course at the Royal Institution that ran during summer 2013.

I try to be as generous with my time for enquiries as I can. This has lead me to offering advice and assistance from large organisations such as BBC, and the Science Media Centre through to individuals.

As well as personally talking about climate science, I've been thinking about the best way that dialogue should take place. Firstly, where possible it should actually be a bespoke dialogue rather than an information-deficit barrage of facts. This has lead me to be involved with a policy commission based at UCL. We have given evidence to Parliament and authored a cross-disciplinary report on the topic. I use these findings to give a seminar to my MSc students on climate science communication and we are developing a short course for PhD students.

Teaching

I am responsible for the MSc in both Climate Change and Environmental Modelling that are run by UCL Geography.

1st Year GEOG1002 Environmental Systems and Processes – An introductory course providing a comprehensive understanding of the fundamentals of the Earth's atmosphere, hydrosphere, lithosphere, and biosphere. I contribute lectures on weather, climate and climate change.
2nd Year GEOG2020 Hydroclimatology – A course introducing the water cycle including components on meteoric water, surface water and ground water. I contribute lectures on the atmospheric water budget and climate variability.
3rd Year GEOG3037 Climatology – This course describes the workings of the climate system and provides an introduction to climate modelling. I convene the course and deliver all the content. Not currently delivered.
GEOGG120 Models in Environmental Science – A course aimed at introducing students to a broad range of environmental models, interspersed with hands-on practice and theory. I contribute a class on climate models.
GEOGG134 Climate Modelling – Explains how the equations that describe the atmosphere and ocean are solved numerically to create meaningful predictions. Involves running HadAM3, so is heavy on the practical side. I convene the course and deliver all the content.
GEOGG130 Climate Dynamics – A course focused on the climate system: how we observe it, how we explain and what we project for its future. I convene the course and deliver all the content.
GEOGG133 Past Climates – A course describes the previous history of the climate system along with techniques of palaeoclimate reconstruction. I contribute a lecture on role of climate models in palaeoclimate.

Short Courses at the Royal Institution

Week 1. The Current Climate [description of today's climate along with the Earth's energy budget]. Keynote weblink, PDFs with 1, 2 or 4 slides per page.
Week 2. A Changing Climate [covering modes of variability, drivers of climate change and feedbacks]. Keynote weblink, PDFs with 1, 2 or 4 slides per page.
Week 3. Future Climate [covering climate models and IPCC AR5 projections]. Keynote weblink, PDFs with 1, 2 or 4 slides per page.
Week 4. Climate Impacts [covering oceans, biosphere and tipping points]. Keynote weblink, PDFs with 1, 2 or 4 slides per page.
Week 5. Risks [covering groundwater, hurricane exposure and health impacts]. Keynote weblink, PDFs with 1, 2 or 4 slides per page.
Week 6. Actions [covering mitigation and final thoughts].  Keynote weblink, PDFs with 1, 2 or 4 slides per page.
Introduction to Paleoclimates, G&G 402/602 . This is a graduate and upper-level undergraduate course on paleoclimate. The aim of the course was to provide students with an introduction to interesting climate periods in the Cenozioc (past ~65Ma). It married geochemical analysis with climate modelling to create a more complete understanding of the climate system. I co-taught this course with Prof. Mark Pagani.
Theory of Climate, G&G 523/323. A graduate and upper-level undergraduate course on climate dynamics. I contributed two lectures on Ice Ages.
Physical Oceanography, G&G 535/335. A graduate and upper-level undergraduate course introducing students to basic concepts in physical oceanography. I contributed a lecture on Air-Sea interactions.
The Physical Science of Global Climate Change G&G 702. A graduate seminar class, whose reading material was working group I of the latest IPCC (intergovernmental Panel on Climate Change) report. I was brought in to provide expert knowledge in the later chapters on climate models and their projections.

PhD Students

PhD research students

I have two projects listed at the London NERC DTP:

Masters Students

  • 2013 Sarah Cripps Impact and management of climate change on rice farming in Gujarat, India
  • 2013 Tino Kretschmer CO2 and black carbon concentrations in central London [Distinction]
  • 2013 Kanhe Wang Climate change and GDP: statistic analysis through linear regression
  • 2012-2013 Matthew Raywood Mapping tropical cyclone induced vertical diffusivities and a sensitivity analysis of surface drag coefficient [Distinction]
  • 2012 Heidi Richardson The effect of disturbance on the bottlenose dolphin (Tursiops trucatus) in Cardigan Bay in Wales [Distinction]