- Is climate chaotic? It the chaotic behavior
limited in the atmosphere only? Or is it also in other elements of
the climate system, such as the oceans and cryosphere? Will the
chaotic behavior be amplified when the atmosphere is coupled together with
the oceans and cryosphere? Is there is a limit to our ability to predict
climate beyond a certain time range? To what extent, a climate model can
be simplified to produce the chaotic behavior?
- Natural Variability. Will a chaotic
system always have a well defined attractor, i.e., a well defined
distribution describing the probability of occurrence of various climates?
Does the natural variability of climate arise from the climate system's
chaotic elements? Will the distribution itself be predictable beyond the
limit of deterministic predictability? Is the natural variability of the
climate system on time scales of decades and longer dependent on oceanic
and cryospheric processes only? How much do we understand this natural
variability based on paleoclimatic evidence?
- Errors in Initial Conditions. To what
extent does the ability to predict future behavior depend on the accuracy
of the knowledge of the system's initial state? How does the ability
differ for a chaotic or a non-chaotic system? Do we know how
accurately we need to know the temperatures of the deep ocean today in
order to make a prediction of climate of a given accuracy, say, fifty
years in the future? Given the long time scales of the deep ocean
circulations, the climate trends of the coming decades may be crucially
dependent on the history of climate during the last few centuries. What is
the extent of this dependence?
- Model Errors. Would our climate
predictions be hampered by the imperfect state of current climate models
even if the above factors did not introduce limits on our ability to
predict climate? Are there any coupled atmosphere-ocean general
circulation models which are able to reproduce a climate equilibrium like
the current climate without introducing artificial sources of heat,
moisture, and/or momentum at the interface between the atmosphere and the
oceans (i.e., "flux corrections")? Do we know the source or sources of
these errors? Why do you think the potential sources include inadequate
resolution of oceanic currents and eddies, and inadequate representations
of subgrid scale processes such as moist convection and clouds in the
atmosphere? The need to parameterize subgrid scale processes may introduce
severe limitations on our ability to represent these processes and their
impact on climate change, and we need to understand these limitations and
the resulting uncertainty.
- Can we trust what the climate models tell us and why?