Announcement of Opportunity: Scoping group for reducing uncertainty in climate sensitivity due to clouds

Closing date: 16:00 on 4 April 2018

NERC invites applications to join a scoping group that will develop the science case for a potential large strategic research programme on reducing uncertainty in climate sensitivity due to clouds.

This is one of three potential strategic programme areas (SPAs) which have emerged from the ideas process for strategic research. We do not expect to be able to fund all three potential SPAs, and any potential SPA must meet NERC's criteria for a strategic programme, so it is possible that none of them will result in funded programmes.

Lack of understanding of physical processes in clouds, including interactions with aerosols, is the largest source of uncertainty in estimates of climate sensitivity (IPCC report, 2014). Two recent papers published in Nature reached dramatically different conclusions about plausible climate sensitivity values, suggesting considerable scientific uncertainty remains.

Climate sensitivity estimates underpin climate policymaking by defining the carbon 'headroom' available to society or the degree to which society must adapt to climate change. Laboratory experiments, field instrumentation, and models have all now advanced to a point where a coordinated research programme can improve our estimates of climate sensitivity.

This potential SPA will address the scientific problem by bringing experts in aerosols, chemistry, land surfaces, clouds and climate, in a coordinated end-to-end approach. The result will be ultimately to produce demonstrable skill improvements and reduced uncertainty in global climate modelling, which itself requires a definition of skill in this field to be developed.

Cloud processes involve phase changes, heat and mass transfer on scales from that of the ice crystal lattice spacing to the depth of the tropical troposphere. Climate models represent these processes in a highly parameterised way (capturing the larger-scale effects of a process rather than the unresolved smaller-scale causes). There have been advances in the understanding of climate feedbacks associated with changes in low-level liquid clouds, but precipitation processes and small-scale dynamical feedbacks add significant uncertainty to feedbacks.

In other cloud regimes, such as deep tropical clouds involving mixed ice-and-water microphysics, there is a lack of understanding of the key aerosol and cloud processes, interactions between these processes, and their parameterisation. A new SPA will focus attention on one of these cloud regimes having identified its real potential to reduce uncertainty in our estimates of climate sensitivity.

Potential research questions

Making strategic advances will involve four principal scientific areas:

  • aerosol-mediated cloud feedback
  • glaciation of clouds
  • precipitation processes
  • cloud-scale dynamics.

The processes involved all interact and feed back on each other, making proper representation in models challenging.

Building on recent advances, including radar observation of individual falling water particles in clouds, and improved laboratory and molecular dynamics results on ice nucleation, the following research questions could be addressed:

  1. What are the roles played by ice nucleating particles (INP) and cloud condensation nuclei (CCN) in modulating cold precipitation formation, or giant cloud condensation nuclei (GCCN) in modulating warm precipitation formation?
  2. What are the dominating physical processes in the generation of ice particles in mixed-phase clouds and the progression of cloud glaciation?
  3. What cloud microphysical processes are most important for precipitation formation in the specific cloud types and temperature regimes chosen, and thus which physical processes should be represented in large-scale models?
  4. What are the effects of dynamical and turbulent processes on cloud particle growth and the feedback effects of cloud and precipitation processes on cloud dynamics?
  5. What is the impact of these processes on radiative and other climate feedbacks?

Applications are invited from individuals wishing to join the scoping group that will develop the science case for consideration by NERC.

Scoping group meeting

Professor Joanna Haigh of Imperial College London has agreed to chair the scoping group. Members will be selected by NERC via an open call for self-nomination. It is anticipated that the scoping group will be made up of around six- eight individuals and will have an appropriate scientific balance. Members of the scoping group are expected to act as representatives of their scientific disciplines, and to act in the interests of the scientific community as a whole, rather than representing personal or institutional interests.

The composition of the group will be decided by NERC with input from the Chair of the scoping group and a representative of NERC's Strategic Programme Advisory Group (SPAG). NERC reserves the right to appoint members to the scoping group who haven't applied to achieve the balance of representation required.

The scoping group will convene for a one-day meeting which all members must attend. The group will be tasked with producing a science case by the end of June 2018. This meeting will take place on Monday 23 April 2018 at a venue in the London area. By applying to join this scoping group you are confirming your availability to attend this meeting.

If the proposed research programme is approved, members of the scoping group will be able to apply for funding, subject to normal NERC eligibility rules.


Applicants should submit their application via the online form by 16:00 on 4 April 2018. Successful applicants will be informed of the outcome by 12 April 2018.

NERC will cover all reasonable travel and subsistence associated with attending the meeting, in line with NERC policy.

To register for this event, please complete the online registration form.


Simon Howe