Science plan
Source: environment.data.gov.uk (2018-06-19)

RAPID Quantitative applications of high-resolution late Holocene proxy data sets: estimating climate sensitivity and thermohaline circulation influences numerical model and observational data. This collection contains data from "The Quantitative applications of high-resolution late Holocene proxy data sets: estimating climate sensitivity and thermohaline circulation influences" project, which was a Natural Environment Research Council (NERC) RAPID Climate Change Research Programme project (Round 1 - NER/T/S/2002/00440 - Duration 1 Jul 2003 - 30 Jun 2008) led by Prof Keith Briffa of the University of East Anglia, with co-investigators at the University of East Anglia.

This dataset collection contains self-calibrating Palmer Drought Severity Index data.

This project analysed the output from state-of-the-art coupled climate models in conjunction with very long instrumental climate data and an extensive archive of annual- and selected decadal-resolution palaeoclimate data to study climate changes during the past millennium. Actual and model-derived synthetic networks of palaeoclimate data have been used to estimate the extent to which (i) variations in Atlantic meridional overturning circulation strength; (ii) variations in the North Atlantic Oscillation; and (iii) the sensitivity of climate to external forcing changes can be reconstructed from different networks of palaeoclimate data, making assumptions about coverage, seasonality of response and reliability of expressed climate signal.

Rapid Climate Change Science Plan
• 
Executive Summary
• 
Objectives
• 
Deliverables
• 
Background
• 
Research Programme
• 
Training
• 
The Community
• 
Collaboration and links with other programmes
• 
Resources
• 
Project Management
• 
Data Management
• 
References
Science Plan
To improve our ability to quantify the probability and magnitude of future rapid change
in climate
Executive Summary
Studies of past climate suggest that large and rapid (as fast as 10-20 years) changes
have occurred and that changes in the ocean’s thermohaline circulation (THC) are
often a major factor. Modelling studies show that the THC and the heat that it
transports northward in the Atlantic produces a substantially warmer climate in
western Europe than would otherwise be the case. They also predict that under a
global greenhouse-gas warming situation the THC might slow down, possibly leading
to a cooling of western Europe, which could have significant socio-economic impacts.
A limited number of observations of the North Atlantic THC are available and, of the
few that are, some suggest that a slow down of the THC might be occurring now.
The programme therefore aims to investigate and understand the causes of rapid
climate change, with a main (but not exclusive) focus on the role of the Atlantic
Ocean’s THC. Using a novel combination of present day observations, palaeo data
and a hierarchy of models (from local process models to global general circulation
models) the programme will improve our understanding of the roles of the THC and
other processes in rapid climate change, and of the global and regional impacts of
such change. As a result, our ability to monitor and predict future rapid climate
change, particularly in the North Atlantic region, will be enhanced. This will be
achieved by undertaking improved observations of the Atlantic THC and the
processes that influence it; by using improved palaeo data to reconstruct past
changes; by combining the present-day and palaeo observations with models, in
order to test and improve them; and by using the understanding gained to assess the
probability and magnitude of future rapid climate change.
The programme will deliver: an assessment of the probability and magnitude of future
rapid climate change; an improved observing system for the THC; better
understanding of the processes that “drive” the THC; improved palaeo-climate data
and new methods for using these data with models; improved models for predicting

rapid climate change, giving greater confidence in the predictions; and scenarios that
can be used in risk assessments by those studying the impacts of climate change.
The programme has been funded by NERC at a level of £20M over a period of 6
years. The programme will bring together the diverse research communities that
have the skills to address the problem, and will provide training and opportunities for
new researchers. Given the scale of the problem, it will also actively seek
international collaborations that complement and enhance the work being carried out.
Objectives
The purpose of the RAPID programme is to improve our ability to quantify the
probability and magnitude of future rapid change in climate. The programme aims to
investigate and understand the causes of rapid climate change, with a main (but not
exclusive) focus on the role of the Atlantic Ocean’s thermohaline circulation (THC).
Using a combination of observations (present day and palaeo) and modelling
(atmospheric, oceanic, terrestrial, cryospheric) the programme will study rapid
climate change, with a focus on the key role of the THC in such change. The
programme will seek to observe the present operation of the THC, to infer its time
evolution from palaeo data, to understand what processes might change or stabilise
the THC, and to assess the climatic consequences (atmospheric, oceanic, terrestrial,
cryospheric) of such changes. The aim is to quantify under what conditions a
weakening of the THC would occur, as an essential precursor to predicting when this
may happen. Observations will be made that are crucial for testing simulations of
THC variability and climate change. Palaeo data will be used to reconstruct past
changes of the climate system, with a particular focus on rapid changes and a
geographical emphasis on the expression of such changes in the North Atlantic
region. The programme will use palaeo-reconstructions of past climate and
observations to test and improve models. This will include a focus on the individual
and linked processes that are simulated in climate models, with the aim of improving
prediction of potential future rapid climate change.
Specific objectives of the programme are:
• To establish a pre-operational prototype system to continuously observe the
strength and structure of the Atlantic meridional overturning circulation (MOC).
• To support long-term direct observations of water, heat, salt, and ice transports at
critical locations in the northern North Atlantic, to quantify the atmospheric and
other (e.g. river run-off, ice sheet discharge) forcing of these transports, and to
perform process studies of ocean mixing at northern high latitudes.
• To construct well-calibrated and time-resolved palaeo data records of past climate
change, including error estimates, with a particular emphasis on the quantification
of the timing and magnitude of rapid change at annual to centennial time-scales.
• To develop and use high-resolution physical models to synthesise observational
data.
• To apply a hierarchy of modelling approaches to understand the processes that
connect changes in ocean convection and its atmospheric forcing to the large-
scale transports relevant to the modulation of climate.

• To understand, using model experimentation and data (palaeo and present day),
the atmosphere’s response to large changes in Atlantic northward heat transport,
in particular changes in storm tracks, storm frequency, storm strengths, and
energy and moisture transports.
• To use both instrumental and palaeo data (see 1-3) for the quantitative testing of
models’ abilities to reproduce climate variability and rapid changes on annual to
centennial time-scales. To explore the extent to which these data can provide
direct information about the THC and other possible rapid changes in the climate
system and their impact.
• To quantify the probability and magnitude of potential future rapid climate change,
and the uncertainties in these estimates.
The above objectives are clearly inter-linked. Thus our ability to predict future climate
change (8), rapid or otherwise, is predicated on understanding the current state of
the climate (particularly a key component like the THC; 1-2) and past changes in
climate (3), on developing models necessary to investigate the THC and climate (4),
on using the models to investigate how the climate system works (5-6) and to test the
response of the whole system (7). It is the novel combination of present day
observations, palaeo data and a hierarchy of models (from local process models to
global general circulation models - GCMs) that will improve our understanding of the
roles of the THC and other factors in the processes leading to rapid climate change.
It will also improve our understanding of the global and regional impacts of such
change and our ability to monitor and predict potential future rapid climate change.
Deliverables
The primary deliverable will be a quantitative assessment of the probability and
magnitude of potential future rapid climate change, and the uncertainties in these
estimates. A key deliverable will be the identification of the critical observations that
will eventually be part of an operational long-term Atlantic MOC observing system.
Moreover, the programme will produce recommendations for future climate model
development, to increase confidence in projections of THC and climate change.
Specific deliverables are:
• A proven, field-tested and cost-effective design for an operational monitoring
system for the Atlantic MOC.
• Identification of main drivers of THC variability.
• Identification of consequences for climate of rapid change of the THC, including
scenarios for use in risk assessments.
• Improved palaeo-climate data sets with associated error estimates and sufficient
temporal resolution to identify variability and rapid change on annual to centennial
time-scales.
• Improved methods for using palaeo-climate data for quantitative testing of
models.
• An assessment of the ability of climate models to simulate rapid change and the
role of the THC variability in such change, and recommendations for model
development to reduce uncertainty in projections of THC and other rapid changes
in climate and their impacts.
Background
A wide range of model studies unanimously show that the presence of the THC and
its associated heat transport produces a substantially warmer climate in western

Europe than would otherwise be the case (Manabe and Souffer 1988, Schiller et al.
1997, Vellinga and Wood 2001, Seager et al. 2001). The THC consists of deep
convection induced by surface cooling at high latitudes, sinking to depth, and
upwelling of deep waters at lower latitudes, with horizontal shallow and deep currents
feeding these vertical flows. The deep convection and sinking in the North Atlantic (in
the Labrador and Greenland Seas) have no counterpart in the North Pacific Ocean,
where northward heat transport is consequently much weaker. However, the Atlantic
THC has not always been like today’s. Palaeo climate records prove that massive
and abrupt climate change has occurred in the Northern Hemisphere, especially
during and just after the last cold stage (Broecker and Denton, 1989, Dansgaard et
al., 1993, Broecker, 2000b), with THC change as the most plausible mechanism.
Similar change might occur in the future. Model results suggest that the human-
induced increase in the atmospheric concentration of CO2 and other greenhouse
gases will lead to a significant reduction in THC strength in the Atlantic (e.g., Manabe
and Stouffer, 1993; Wood et al., 1999). This in turn will modify substantially the
projected rate of climate change over western Europe. Furthermore, it is possible that
the changes in the strength of the THC could occur rapidly, perhaps over just 10-20
years. Such large, rapid climate change would make adaptation to, and mitigation of,
the impacts exceedingly difficult for the affected countries. Therefore, it would be
useful to estimate the probability of such changes. However, while most climate
models indicate that there will be THC weakening, there is considerable spread
between their projections (Cubasch et al, 2001), and at least two models show no
change at all (Latif et al., 2000, Gent 2001). Hence, the climate research community
is faced with both a challenge and an opportunity.
There is a possibility that the North Atlantic THC will undergo changes that will result
in substantial and rapid climate change for western Europe and Scandinavia, but we
cannot reliably quantify the probability of this occurring. In order to have a context in
which to assess the probability of a future rapid change in the THC and climate, it is
also necessary to understand other potential drivers of rapid change and the intrinsic
variability of the climate system. Over recent years progress has been made in
acquiring palaeo observations of past rapid climate change (Dansgaard et al., 1989;
Alley et al., 1993; Koç Karpuz & Jansen, 1992) and Holocene climate variability
(Mann et al 1998, 1999, Briffa et al 2001), and in developing climate models that
might be used to predict such change. However, this work is currently largely
disjointed and generally lacking in estimates of uncertainty. So a further challenge
and opportunity exists in bringing together the palaeo data and the climate models,
and also in developing estimates of uncertainty. (McAvaney et al. 2001 summarises
the current state of climate models and the uses of palaeo data that have been made
so far for model testing). This will aid understanding of rapid climate change and the
intrinsic variability of the system, and test the climate models’ abilities across a range
of time scales that is greater than that for which instrumental records exist.
Research Programme
The programme will support research that addresses the objectives in the following
areas:
1)
Observing the Atlantic meridional overturning circulation (MOC):
Present observations of the Atlantic MOC (of which the THC is the dominant
component) are insufficient to detect whether it is changing. Thus a significant
weakening of the MOC may already be in progress, unnoticed. In order to detect

such change and to develop predictive capabilities for the MOC it is necessary to
monitor it, akin to the necessity of observing the equatorial Pacific if one wants to
forecast El Niño. Therefore the programme will support work to develop and
implement a prototype pre-operational system to observe the Atlantic MOC strength
and structure. It is the ocean heat transport (and hence the MOC) around 25-35N
that is most relevant for western European climate, because much of this heat is
given off to the atmosphere between 35 and 50N, from where it is transported north-
eastward towards Europe by the atmosphere. Therefore it will be necessary for the
observing system to be able to monitor changes that affect this heat transport. As a
minimum requirement the observing system should be able to monitor the strength
and structure of the Atlantic MOC on time scales from months to decades, and
collect about 3-4 years of continuous data during the course of the programme. The
observations acquired by the system will need to be analysed to show that they
provide the required information to an acceptable accuracy. A cost-effective design
for an operational version of the monitoring system, and any technological and other
developments necessary to its implementation, will be produced.
2) 
Northern high latitude observations, long-term transports and mixing
processes:
In addition to observing change in the THC overturning rate the programme will
support studies to learn more about which northern high latitude processes and
regions are responsible for the observed changes. Observations show significant
changes over the past few decades in the temperature of the warm Atlantic currents
flowing towards the Arctic Ocean and in the outflows of fresh water and ice from the
Arctic Ocean. Arctic sea ice volume has shrunk dramatically over the past decades
(Vinnikov et al., 1999; Johannessen et al., 1999; Rothrock et al., 1999). These recent
changes affect the characteristics of the cold deep overflows (Østerhus and
Gammelsrod, 1999; Turrell et al., 1999; Hansen et al., 2001), which cross the
Greenland-Scotland Ridge southwards to “drive” the THC. Modelling results suggest
that an increase in the southward flux of freshwater through Fram Strait is able, in a
few years, to reduce the intensity of the THC in the North Atlantic. However, the
models are not necessarily reliable, since there are no direct measurements of some
of the key ocean fluxes involved to test their results against. These include the net
poleward flux of heat and salt to the Arctic Ocean through the three main gateways
(Fram Strait, Barents Sea and Bering Strait) and the net equator-ward flux of ice and
freshwater through the two main pathways (southward along the East Greenland
shelf and through the Canadian Arctic Archipelago). Model improvement thus
depends on obtaining these measurements, and on doing so over a long enough
period to capture their variability. Since the most advanced models now suggest a
link between the time-dependence of certain of the ocean fluxes at different Arctic
gateways, these measurements ultimately need to be made simultaneously and for
several decades. The programme will support work that contributes to this long-term
measurement requirement.
It may prove difficult to partition the northern high latitude influences on the THC of all
heat, ice, and freshwater fluxes (including terrestrial run-off) into their separate
components in a quantitative way, but establishing their relative importance is crucial.
Many of the transformation processes at high latitudes take place at small spatial
scales, but the integral properties of the mixing probably depend on regional scale
patterns of surface buoyancy flux and on the underlying stratification. Hence there is

a need to determine the heat and water budgets (mean and variability). Given the
existing work of the Labrador Sea Group (1998), this programme will primarily
support studies that concentrate on the Nordic Seas. Establishing budgets will
involve all the direct measurements in the Nordic Seas, including the mixing
processes discussed below, and the model-data synthesis efforts (see 4 below).
The programme will also support studies of mixing processes such as convective and
non-convective vertical mixing, interaction with topography (boundary mixing), sea-
ice interactions, and the dynamics of overflows. These are known to be important for
the THC but are poorly understood. The processes all have short space and time
scales, making it impossible to model them from first principles in coupled GCMs.
The effects of these processes must be parameterised in models, but the processes
need to be well understood if the models are to have predictive skill. The programme
will support experiments to increase the understanding of the key mixing processes
in the Nordic Seas and their influence on the circulation in the Nordic Seas and the
overflows. Possible approaches are tracer and direct turbulence measurements,
which are powerful and mutually supporting techniques, and the integration of data
with models (see 4 below).
3) 
Constructing well-calibrated and time-resolved palaeo data records:
There exists a wealth of indicators of past climate, which indicate that rapid changes
have taken place and could be used to estimate the range of “normal” climate
variability. The programme will support investigations into components of the climate
system that have the potential for future rapid change, that would have major
regional or global climatic repercussions. These studies will involve a combination of
palaeo-climate reconstructions (using instrumental records and high-resolution
natural archives, preferably with annual temporal resolution) and modelling (see 7
below). The palaeo studies are generally expected to focus on periods of rapid
change (e.g. Dansgaard-Oeschger and Bond cycles, Heinrich events, possible
abrupt cooling during interglacials) and the recent Holocene, and to obtain data with
accurate dating and improved temporal resolution.
To enable the data to be used with models (see 7 below) it will be necessary to
develop methods of integrating and characterising the diverse palaeo indicators on
regional (e.g. the North Atlantic Ocean and surrounding land areas) or larger (up to
global) spatial scales. Additionally, it will be necessary to quantify the uncertainties
associated with both the palaeo data and any resulting climate re-constructions.
Therefore, the programme will support work on new and more robust methods of
reconstructing past climatic changes. This includes the assembly of data with higher
temporal and spatial resolution than have previously been available, and the
provision of data in a manner suitable for use in model validation. It also includes
attempts to calibrate palaeo data against data from existing instrumental records.
Highly resolved temporal data that can be precisely correlated between land, sea and
ice records will be required to determine whether the atmospheric changes drive the
THC changes or vice versa. This inference is of importance to the present-day
situation where we are driving the system through anthropogenic changes in
atmospheric composition.
Direct palaeo-information about ocean circulation is harder to obtain. Progress has
been made recently in a number of areas (e.g. use of isotopic composition of

foraminifera as a density proxy, Lynch-Stieglitz et al., 1999; grain size as a flow
speed proxy, McCave et al., 1995, Bianchi and McCave, 1999), but generally the
oceanic sediment palaeo-record has much lower temporal resolution than that
obtained from ice cores and other palaeo sources (e.g. tree rings, coral bands).
Therefore the programme will support the acquisition of better palaeo data on the
ocean circulation. Using multi-proxy palaeo-records (terrestrial and marine) of high-
resolution sites will allow the study of the interplay between decadal and longer time-
scale climate variability and the THC.
In order to understand rapid, or indeed other changes, in climate and to be able to
run model simulations it is important to know the forcing that is being applied to the
system. Therefore the programme will support studies to establish the climate forcing
that has occurred over different time-scales up to millennial ones. This includes
forcing due to Milankovich cycles, solar and volcanic activity, iceberg discharges from
the Greenland and Laurentide ice sheets, greenhouse gases, atmospheric dust, and
sea ice and vegetation cover changes. These studies will need to link clearly with the
model ones described below (see 7) and focus on periods of rapid change and the
recent Holocene (see above).
4) 
High resolution physical model-observation synthesis:
Even the most intensive observational campaign in oceanography provides
insufficient sampling to extract all the information one needs to understand processes
and budgets. Observational data must be augmented with information from numerical
models, which express the conservation laws governing ocean circulation. This
programme will support work that provides model-observation syntheses based on
the intensive field campaigns (see 1 - 2 above), and which contribute to
understanding and quantifying the key processes and budgets which control THC
stability. The emphasis is on models with high spatial resolution. Although the basic
principles of data assimilation are relatively well understood (Bennett, 1992; Wunsch,
1996), and mesoscale ice-ocean models are available (e.g. Backhaus and Kämpf,
1999), model-observation synthesis of this type has not been performed routinely. An
important and fundamental aspect of regional modelling arises through the need to
specify lateral boundary conditions. In the data assimilation mode, these conditions
can be estimated from the model and the observations. Such an approach has been
implemented in a low-resolution model (Zhang and Marotzke, 1999), but
considerable further exploration is required.
5) 
Atmospheric forcing of ocean convection, and large-scale ocean
transports:
Though a range of climate models suggests that greenhouse warming can lead to
THC weakening, these models all have relatively crude spatial resolution in their
oceanic and atmospheric components. It has never been demonstrated that the THC
can undergo dramatic weakening in ocean and atmospheric climate models of the
resolution and sophistication that is needed to reproduce quantitatively observed
features of ocean circulation, such as the narrowness of fronts and boundary
currents. Many fundamental questions remain unanswered concerning the physics
that controls the stability of the THC. Coupled GCMs are important tools to address
this problem, but their computational expense limits both the physics that can be
resolved and the number of sensitivity studies that can be performed. Two recent
studies of the THC response to increasing atmospheric greenhouse gases with the

HadCM3 coupled model illustrate this. Wood et al. (1999) emphasise the importance
of poorly resolved processes, such as Labrador Sea convection and sill overflows, in
controlling the model response. In contrast, Thorpe et al. (2001) note the importance
of large-scale atmospheric feedbacks (inter-basin water transport) in stabilising the
model THC, in agreement with Latif et al. (2000). The two views are not necessarily
contradictory, but the first implies a need for high resolution modelling of the
overflows to assess the robustness of the HadCM3 results. In contrast, the second
suggests a need to examine the robustness (e.g. sensitivity to poorly known model
parameters) of the basin-scale processes. For the latter, both high resolution GCMs
and low resolution, parameterised models may be necessary. Particular processes
which may be important include: the adjustment of the THC to forcing of the deep
water source (possibly in response to the NAO), through boundary waves and
currents (Kawase, 1987; Marotzke and Klinger, 2000); the response of the THC to
variations in the two deep water sources (Labrador and Greenland-Iceland-
Norwegian Seas; Döscher and Redler 1997); the inhomogeneity of interior mixing
(Polzin et al., 1997; Marotzke, 1997). Low-resolution models have been used to
propose some large scale parameters which may be critical controllers of the THC
and its stability, e.g. large-scale dynamic height contrasts or deep density differences
between North and South Atlantic (Hughes and Weaver, 1994; Rahmstorf, 1996;
Marotzke and Klinger, 2000; Thorpe et al., 2000), or the integrated fresh water
budget of the Atlantic basin (Wang et al., 1999). The programme will support a range
of modelling approaches, of appropriate degrees of complexity, that assess the
robustness of the representation of such processes in the present generation of
climate models.
6) 
Atmospheric response to large changes in ocean heat transport:
Ultimately, it is the atmosphere’s response to THC changes – changes in climate and
weather patterns – that influences societies, more so than oceanic changes (with the
important exceptions of sea level change and influence on ocean ecosystems). In
particular, changes in North Atlantic storm tracks, storm frequency, storm strengths,
and energy and moisture transports are crucial for western European climate.
Furthermore, many of the key processes which control the stability of the THC
involve atmospheric heat and water transports, and are subject to large modelling
uncertainty (e.g. Rahmstorf and Ganopolski 1999, Wood et al 1999, Latif et al. 2000,
Thorpe et al. 2001, Vellinga et al 2001). Therefore, this programme will support
studies that assess the impact of a THC weakening on atmospheric climate. Previous
work with coupled models (e.g. Manabe and Stouffer, 1988;Vellinga and Wood,
2001,) showed a large-scale cooling of the Northern Hemisphere, a possible
Southern Hemisphere warming, and changes to the main precipitation zones in the
tropics. Atmosphere-only GCMs have been used to study the atmospheric response
to large changes in North Atlantic sea surface temperature (SST, e.g., Rind et al.,
1986; Venzke at al., 1999). The programme will support work to confirm these results
with higher-resolution atmospheric models, having much more realistic storm track
representations, and for different scenarios (e.g. changes in North Atlantic heat
transport rather than in SST). Studies aiming to quantitatively estimate the impact of
changes on the terrestrial environment using palaeo-reconstructions alone or in
conjunction with modelling (see 3 and 7) will also be supported.
7) 
Use of palaeo data in ocean and climate models: 

Past occurrences of rapid climate change predate the beginnings of instrumental
climate records (with the possible exception of the early 20th century warming), so
present understanding of these must be tested against palaeo data of all types (from
continental, marine and ice sources). A major effort is needed to confront ocean and
climate models with these observations quantitatively. As noted above (3), direct
palaeo-information about ocean circulations is hard to obtain, but is becoming
available. Even though palaeo-proxy data are often point measurements whereas
models mostly have large grid-boxes, palaeo-time series offer anchor points to test
and evaluate models. Implementation of widely used palaeo-proxies, such as oxygen
isotopes, into model simulations already has produced a series of meridional ocean
palaeo-circulation transects (e.g., Rohling and Bigg, 1998; Schmidt, 1998). The
addition of atmospheric components will help reconcile, in a fully quantitative sense,
the ocean data with the ice core record of rapid climate change. Extra tracers, such
as carbon isotopes and ocean nutrient cycles, will go further towards producing true
quantitative comparisons between the climate models and the palaeo-proxies. This
will allow for an improved interpretation of the palaeo-records and help in the design
of algorithms for relating palaeo-data to meteorological variables. Palaeo-
oceanographic and palaeo-climatic modelling and palaeo data assimilation, including
direct model simulation of oceanographic and climatic palaeo proxies, are therefore
important elements that the programme will support. Rapid climate change events,
such as the 8.2kyr event and the LIA (Little Ice Age), will serve as a more accessible
test-bed for understanding possible large THC-climate interactions during and at the
end of the glacial. Studies of recent Holocene variability will allow an assessment of
“normal” climate variability.
The unusual combination of present day observations, palaeo data and hierarchy of
models (local process models to GCMs) represents an important aspect of the work
of the programme and provides a unique opportunity to test and improve GCMs
(including those used at the Hadley Centre). In particular, the programme will support
the development of a scientific basis for using palaeo data for testing and improving
the individual and linked processes that are used in climate models. Techniques,
such as sensitivity analysis and data assimilation, allow the testing of various
components of the models, focused on their ability to simulate the processes that are
important for THC and other rapid climate change. This should lead to improvements
in the models and reduced uncertainty in prediction of future rapid change.
8) 
Quantifying the probability and magnitude of rapid change:
A key component of the programme is the integration of the results from 1-7 above,
in order to quantify the probability and magnitude of rapid climate change, and
estimate the associated uncertainty. Work supported under this aspect of the
programme includes measuring the statistical variations of the different component
systems that go to make up a climate regime, including the characteristics of extreme
climatic events. This encompasses time-scales from annual to centennial and space
scales from regional to global, with a necessary requirement for firm palaeo dating
control and high and accurate temporal resolution, ideally better than annual (see 3
above). Currently detection and attribution studies use model simulations to estimate
natural climatic variability. Palaeo-data should allow comparison of these estimates
with the variability of the natural system in order to validate these critical
assumptions. The programme will support studies that attempt to quantify
(probabilistically) the likelihood of rapid climate change, and to develop scenarios

that can be used in risk assessments.
Training
Researchers investigating rapid climate change require a broad range of
interdisciplinary skills in palaeo studies, climate, meteorology, oceanography,
numerical modelling, data assimilation, statistics, and computer science. There is a
serious lack of scientists with the required breadth of knowledge and skill to pursue
this scientific “grand-challenge”. The programme will therefore seek to attract
talented scientists from related disciplines and will aim to provide training as
appropriate. It is anticipated that a significant number of Ph.D. studentships will be
allocated.
The Community
A major aim of the programme is to bring together the diverse research communities,
which have the skills to address the problem of rapid climate change. These include
researchers working in physical and tracer oceanography, meteorology, palaeo
studies, sea ice research and atmospheric, oceanic, ice (sea and land) and climate
modelling. In order to break down some of the disciplinary boundaries, proposals that
involve researchers from a variety of disciplines will be particularly encouraged.
Users will be policy makers and the climate community at large, including those
dealing with climate predictability and prediction, and those dealing with the impacts
of, and responses to, climate change. The programme will provide an underpinning
for future climate predictability work and will provide scenarios for use in risk and
impact assessments by social and policy analysts. In particular, this programme will
feed interactively into the recently funded Tyndall Centre for Climate Change
Research, whose focus is on prevention, mitigation, and adaptation strategies. There
will be a strong involvement of the Hadley Centre, which focuses on climate
prediction using GCMs. Collaborative links will be developed with organisations such
as DEFRA, the Environment Agency and the UK Climate Impact Programme
(including identification of their specific needs).
Collaboration and Links with other Programmes
An important aim of the programme is to develop the necessary international
collaborations that will complement and so enhance and extend the NERC and UK
work on rapid climate change. A key collaboration, arising from discussions between
the Prime Ministers of the UK and Norway, will be with the Norwegian Ocean Climate
project (NOClim; http://www.noclim.org). A high priority will be given to developing
the UK–Norway initiative into a genuine scientific collaboration of mutual benefit. The
RAPID has natural links with a number of NERC, UK and international programmes –
either existing or planned. These include COAPEC, AUTOSUB\ICE, UGAMP (all
NERC), CONVECTION, TRACTOR, VEINS, MAIA, OPEC2, PREDICATE (all EU),
Clic, CLIVAR (GOALS, DecCen, ACC), IGBP (PAGES), HOLIVAR, ODP, IODP,
IMAGES, ARGO, ERS-2, ENVISAT, GOCE, SMOS, CRYOSAT, TOPEX, JASON-1,
ICESAT, GRACE, Florida Straits monitoring, ASOF (all international) and various
modelling ventures, particularly (as noted above) those at the Hadley Centre.
Resources
The NERC Science and Technology Board (STB) has allocated £20M to RAPID over
six years. The funding profile of the programme will be decided by the Scientific
Steering Committee.

Project Management
The programme has a steering committee appointed by NERC to provide scientific
direction. The NERC Superintending Officer is Dr. Phil Newton and the Programme
Co-ordinator is Dr. Andy Parsons. An RAPID programme office has been established
at the Southampton Oceanography Centre under the Scientific Co-ordinator Dr.
Meric Srokosz.
Data Management
It is NERC policy that thematic programmes ensure the long-term availability of data
collected, to maximise the application and exploitation of the results. In most cases, it
is expected that NERC Designated Data Centres will be used for quality control and
archiving, with costs covered from programme funds. After a period of sole access by
PIs for publication preparation, data are made available to other programme
participants and the wider community.
Appendix A: References
Alley R.B. et al. 1993. Abrupt increase in Greenland snow accumulation at the end of
the Younger Dryas event.  Nature, 362, 527-9.
Alley R. B., P. A. Mayewski, T. Sowers, M. Stuiver, K. C. Taylor, P. U. Clark 1997
Holocene climatic instability: A prominent, widespread event 8200 yr ago, Geology,
25, 483-486.
Backhaus, J.O. and J. Kämpf (1999). Simulations of sub-mesoscale oceanic
convection and ice-ocean interactions in the Greenland Sea. Deep-Sea Res.II, 46,
1427-1456.
Bennett, A. F., 1992: Inverse Methods in Physical Oceanography. Cambridge Univ.
Press, Cambridge, 346pp.
Bianchi, G.G. and McCave, I.N., 1999: Holocene periodicity in North Atlantic climate
and deep-ocean flow south of Iceland. Nature, 397, 515-517.
Bond, G., et al., 1997: A pervasive millennial-scale cycle in North Atlantic Holocene
and glacial climates, Science, 278, 1257-1266.
Briffa KR, Osborn TJ, Schweingruber FH, Harris IC, Jones PD, Shiyatov SG,
Vaganov EA 2001 Low-frequency temperature variations from a northern tree ring
density network, J Geophys Res, 106, 2929-2941.
Broecker, W. S., 1997: Thermohaline circulation, the Achilles heel of our climate
system: Will man-made CO2 upset the current balance? Science, 278, 1582-1588.
Broecker, W. S., 2000: Was a change in thermohaline circulation responsible for the
Little Ice Age? Proc. Nat. Acad. Sci. (USA), 97, 1339-1342.
Broecker W.S. 2000b Abrupt climate change: causal constraints provided by the
paleoclimate record, Earth-Science Reviews, 51, 137-154.
Broecker, W.S., and G.H. Denton, 1989: The role of ocean-atmosphere
reorganisations in glacial cycles, Geochim. Cosmochim. Acta, 53, 2465-2501.
Bryan, F., 1987: Parameter sensitivity of primitive equation ocean general circulation
models, J. Phys. Oceanogr., 17, 970-985.
Cubasch, U., G.A. Meehl, G.J. Boer, R.J. Stouffer, M. Dix, A. Noda, C.A. Senior, S.
Raper and K.S. Yap, 2001: Projections of future climate change. In Climate Change
2001: the scientific basis. Contribution of Working Group 1 to the Third Assessment
Report of the Intergovernmental Panel on Climate (J.T. Houghton et al., editors),
Cambridge University Press, 881pp.

Dansgaard W., White JWC, and Johnsen, S J, 1989. The abrupt termination of the
Younger Dryas climate event. Nature, 339,532-4.
Dansgaard, W., et al., 1993: Evidence for general instability of past climate from a
250-kyr ice-core record. Nature, 364, 218-220.
Dickson, R.R., J. Meincke, S.A. Malmberg, and A.J. Lee, 1988: The Great Salinity
Anomaly in the northern North-Atlantic 1968-1982. Prog. Oceanogr, 20, 103-151.
Dickson, R.R., T. J. Osborn, J. W. Hurrell, J. Meincke, J. Blindheim, B. Adlandsvik, T.
Vinje, G. Alekseev, and W. Maslowski, 2000: The Arctic Ocean Response to the
North Atlantic Oscillation. J. Climate, 13, 2671-2696.
Dickson, R. R.; Meincke, J.; Turrell, W. R.; Dye, S. R.; Yashayaev, I. M., and Holfort,
J. 2001 First evidence of a deep ocean response to high latitude climate forcing.
Nature. Submitted.
Dong B.-W. and R.T. Sutton, 2001: The dominant mechanisms of variability in
Atlantic ocean heat transport in a coupled ocean-atmosphere GC. Geophysical
Research Letters, 28, 2445-2448.
Gent, P.R., 2001: Will the North Atlantic Ocean thermohaline circulation weaken
during the 21st century? Geophys. Res. Lett., 28, 1023-1026.
Hansen, B. and Kristiansen, R. 1999 Variations of the Faroe Bank Channel overflow.
Rit Fiskideildar, 16, 13-22.
Hansen, B.; Turrell, W. R., and Østerhus, S. 2001 Decreasing overflow from the
Nordic seas into the Atlantic Ocean through the Faroe Bank Channel since 1950.
Nature, 411, 927-930.
Hoskins, B.J. and Valdes, P.J., 1990:  On the existence of storm-tracks. J. Atmos.
Sci., 47, 1854-1864.
Hughen, K. A., et al., 1998: Deglacial changes in ocean circulation from an extended
radiocarbon calibration. Nature, 391, 65-68.
Hughes, T.C.M., and A.J. Weaver, 1994: Multiple equilibria of an asymmetric two-
basin ocean model. J. Phys. Oceanogr., 24, 619-637.
Johannessen, O.M., E.V. Shalina, and M.W. Miles, 1999: Satellite evidence for an
Arctic sea ice cover in transformation. Science, 286, 1937-1939.
Kanzow, T., 2000: Integrale Erfassung langperiodischer Transporte: Simulation und
Optimierung eines verankerten Systems. Diplomarbeit (Masters Thesis), Univ. Kiel,
Germany, 95pp (in German).
Kawase, M., 1987: Establishment of deep ocean circulation driven by deep-water
production. J. Phys. Oceanogr., 17, 2294-2317.
Keigwin, L.D. 1996 The Little Ice Age and Medieval Warm Period in the Sargasso
Sea.  Science, 274, 1504-1508
Keigwin, L.D. & Pickart, R.S., 1999. Slope water current over the Laurentian Fan on
interannual to millennial time scales. Science, 285, 520-523.
Koç Karpuz, N & Jansen, E, 1992. A high resolution diatom record of the last
deglaciation from the S.E. Norwegian Sea: documentation of rapid climatic changes.
Paleoceanography, 7, 499-520.
Kwok, R., and D.A. Rothrock, 1999: Variability of Fram Strait ice flux and North
Atlantic Oscillation, J. Geophys Res., 104, 5177-5189.
Lab Sea Group, The, 1998: The Labrador Sea Deep Convection Experiment. Bull.
Am. Met. Soc., 79, 2033–2058.
Larsen, J.C., 1992: Transport and heat flux of the Florida Current at 27N derived
from cross-stream voltages and profiling data: theory and observations. Phil. Trans.
Roy. Soc. London, A, 338, xx-xxxx-xxxx.

Latif, M., E. Roeckner, U. Mikolajewicz, and R. Voss., 2000: Tropical stabilisation of
the thermohaline circulation in a greenhouse warming simulation J. Climate, 13,
1809-1813.
Ledwell, J.R., E.T. Montgomery, K.L. Polzin, L.C. St Laurent, R.W. Schmitt, and J.M.
Toole, 2000: Evidence for enhanced mixing over rough topography in the abyssal
ocean, Nature, 403, 179-182.
Lee, T., and J. Marotzke, 1998: Seasonal cycles of meridional overturning and heat
transport of the Indian Ocean. J. Phys. Oceanogr., 28, 923-943.
Lynch-Stieglitz, J., W. B. Curry, and N. Slowey, 1999: Weaker Gulf Stream in the
Florida Straits during the Last Glacial Maximum. Nature, 402, 644-647.
Manabe, S. and R. J. Stouffer, 1988: Two stable equilibria of a coupled ocean-
atmosphere model. J. Climate, 1, 841-866.
Manabe, S. and R. J. Stouffer, 1993: Century scale effects of increased atmospheric
CO2 on the ocean-atmosphere system. Nature, 364, 215-218.
Mann, M. E. and Bradley, R. S. and Hughes, M. K. 1998 Global-Scale Temperature
Patterns and Climate Forcing Over the Past Six Centuries, Nature, 392, 779-787.
Mann, M. E. and Bradley, R. S. and Hughes, M. K. 1999 Northern Hemisphere
temperatures during the past millennium: inferences, uncertainties, and limitations,
Geophys. Res. Lett., 26, 759-762.
Marotzke, J., 1997: Boundary mixing and the dynamics of three-dimensional
thermohaline circulations. J. Phys. Oceanogr., 27, 1713-1728.
Marotzke, J., and B.A. Klinger, 2000: The dynamics of equatorially asymmetric
thermohaline circulations. J. Phys. Oceanogr., 30, 955-970.
Marotzke, J., R. Giering, K. Q. Zhang, D. Stammer, C. Hill, and T. Lee, 1999:
Construction of the adjoint MIT ocean general circulation model and application to
Atlantic heat transport sensitivity. J. Geophys. Res., 104, 29, 529-29, 547.
McAvaney, B.J., C.Covey, S.Joussaume, V. Kattsov, A. Kitoh, W. Ogana, A.J.
Pitman, A.J. Weaver, R.A. Wood and Z.-C. Zhao, 2001: Model Evaluation. In Climate
Change 2001: the scientific basis. Contribution of Working Group 1 to the Third
Assessment Report of the Intergovernmental Panel on Climate (J.T. Houghton et al.,
editors), Cambridge University Press, 881pp
McCave, I.N. et al., 1995: Sortable silt and fine sediment size/composition slicing:
Parameters for palaeocurrent speeds and palaeoceanography. Paleoceanography,
10, 593-610.
Munk, W., and C. Wunsch, 1998: Abyssal recipes II: energetics of tidal and wind
mixing Deep-Sea Res., 45, 1977-2010.
Østerhus, S. and Gammelsrod, T. 1999 The abyss of the Nordic Seas is warming.
Journal of Climate, 12, 3297-3304.
Polzin, K.L., J.M. Toole, J.R. Ledwell, and R.W. Schmitt, 1997: Spatial variability of
turbulent mixing in the abyssal ocean. Science, 276, 93-96.
Pope, V. D. and R. A. Stratton, 2001: the processes governing horizontal resolution
sensitivity in a climate model. Climate Dynamics, in press.
Rahmstorf, S., 1996: On the freshwater forcing and transport of the Atlantic
thermohaline circulation. Clim. Dyn., 12, 799-811.
Rahmstorf, S., 1999: Shifting seas in the greenhouse? Nature, 399, 523-524.
Rahmstorf, S., and A. Ganopolski, 1999: Long-term global warming scenarios
computed with an efficient coupled climate model, Climatic Change, 43, 353-367.
Rind, D., D. Peteet, W. Broecker, A. Mcintyre, and W. Ruddiman, 1986: The impact
of cold North Atlantic sea surface temperatures on climate: implications for the
Younger Dryas cooling (11-10k). Clim. Dyn., 1, 3-33.

Rohling, E.J., and G.R. Bigg, 1998: Paleosalinity and 18O: a critical assessment. J.
Geophys. Res., 103, 1307-1318.
Rothrock, D.A., Y. Yu, and G.A. Maykut, 1999: Thinning of the Arctic Sea-Ice cover.
Geophys. Res. Let., 26, 3469-3472.
Seager R., Battisti D.S., Yin j., Gordon N., Naik N., Clement A.C. & Canne M.A. 2001
Is the Gulf Stream responsible for Europe’s mild winters?, submitted to Q.J. Roy.
Met. Soc. (see http://www.atmos.washington.edu/~david)
Schiller, A., U. Mikolajewicz and R. Voss, 1997: The stability of the thermohaline
circulation in a coupled ocean-atmosphere general circulation model. Clim. Dyn., 13,
325-347.
Schmidt, G.A. 1998: Oxygen-18 variations in a global ocean model. Geophys. Res.
Let., 25, 1201-1204.
Schulz, H., U. von Rad, & H. Erlenkeuser, 1998: Correlation between Arabian Sea
and Greenland climate oscillations of the past 110,000 years. Nature, 393, 54-57.
Stocker, T. F., and A. Schmittner, 1997: Influence of CO2 emission rates on the
stability of the thermohaline circulation. Nature 388, 862-865
Stommel, H., 1961: Thermohaline convection with two stable regimes of flow, Tellus,
13, 224-230.
Sutton, R. T.  and P-P. Mathieu, Response of the atmosphere - ocean mixed layer
system to anomalous ocean heat flux convergence. Submitted to Quarterly Journal of
the Royal Meteorological Society.
Thorpe, R.B., J.M. Gregory, T.C. Johns, R.A. Wood, and J.F.B. Mitchell, 2001:
Mechanisms underpinning the response of the thermohaline circulation to increasing
greenhouse gases in a non-flux adjusted coupled climate model.  J. Climate, 14,
3102-3116.
Turrell, W. R.; Slesser, G.; Adams, R. D.; Payne, R., and Gillibrand, P. A. 1999
Decadal variability in  the composition of Faroe Shetland Channel Bottom Water.
Deep-Sea Research, 46, 1-25.
Vellinga, M. & R.A. Wood, 2001: Global climate impacts of a collapse of the Atlantic
thermohaline circulation. Climatic Change (in press).
Vellinga, M., R.A. Wood & J.M. Gregory, 2001: Coupled ocean-atmosphere
feedbacks governing the recovery of a perturbed thermohaline circulation. J. Climate
(in press).
Venzke, S.,  M.R. Allen, R.T. Sutton and David P. Rowell, 1999: The atmospheric
response over the North Atlantic to decadal changes in sea surface temperature. J.
Climate, 12, 2562-2584.
Vinnikov, K.Y., et al., 1999: Global warming and Northern Hemisphere sea ice extent.
Science, 286, 1934-1937.
Wadhams, P., and K. Nicholls, 1999: Rapid climate change and the northern high
latitude oceans. Bergen Meeting Report (9/9-11/9 ‘99, 10pp).
Wilkinson, J.P., P. Wadhams and L. Toudal, 1999: Ice motion field over the Odden
area. European Subpolar Ocean Programme Phase 2: the thermohaline circulation in
the Greenland Sea. Final scientific Rep., Appendix b.1.
Wang, X., P. H. Stone, and J. Marotzke, 1999: Global thermohaline circulation, Part I:
Sensitivity to atmospheric moisture transport. J. Climate, 12, 71-82.
Watson, A.J., et al., 1999: Mixing and convection in the Greenland Sea from a tracer-
release experiment, Nature, 401, 902-904.
Whitworth, T., III, 1983, Monitoring the transport of the Antarctic Circumpolar Current
at Drake Passage, J. Phys. Oceanogr., 13, 2045-2057.

Wood, R. A., A. B. Keen, J. F. B. Mitchell, and J. M. Gregory, 1999: Changing spatial
structure of the thermohaline circulation in response to atmospheric CO2 forcing in a
climate model. Nature, 399, 572-575.
Wunsch, C., 1996: The Ocean Circulation Inverse Problem. Cambridge Univ. Press,
New York, 442pp.
Zhang, K.Q., and J. Marotzke, 1999: The importance of open-boundary estimation for
an Indian Ocean GCM-data synthesis. J. Mar. Res., 57, 305-334.