This is the first of two pieces on the recent IPCC workshop in Hawaii, This brought together independent researchers from all over the world to analyse computer model simulations of the last 150 years and to assess whether they are actually any good.
Guest commentary from Natassa Romanou (Columbia University)
During the first 3 days of March 2005, balmy downtown Honolulu in Hawaii was buzzing with agile scientists conversing, chatting, announcing, briefing and informing about IPCC assessment reports, climate models, model evaluations, climate sensitivities and feedbacks. These were the participants of the Climate Model Evaluation Project workshop (CMEP) and came here from most (if not all) the major, most prestigious climate research laboratories of the world, including; The US labs National Center for Atmospheric Research, the Geophysical Fluid Dynamics Laboratory and the Goddard Institute for Space Studies, the British Hadley Centre for Climate Prediction, the German Max Planck Institute for Meteorology, the Canadian Centre for Climate Modelling and Analysis, the French Centre National de Recherches Meteorologiques and the IPSL/LMD/LSCE, the Australian CSIRO Atmospheric Research, the Chinese Institute of Atmospheric Physics, the Russian Institute for Numerical Mathematics and the Japanese Meteorological Research Institute. This meeting was sponsored by the benevolent NSF, NOAA, NASA and DOE.
Why all this hoopla? Well, because soon (as soon as December 2005) the leading authors of the Intergovernmental Panel on Climate Change (aka IPCC) Assessment Report #4 (AR4) will have to decide what the current knowledge in climate state, modeling and climate projection estimates is, so as to include it in the next report.
If you have not heard, IPCC was established by the World Meteorological Organization and UNEP to assess scientific, technical and socio- economic information relevant for the understanding of climate change, the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation. To be exact, IPCC does not do the research. It only collects peer-reviewed publications, evaluates them through an expanded appraisal process and publishes it. How? The IPCC has three Working Groups and a Task Force. Working Group I (WGI) assesses the scientific aspects of the climate system and climate change , Working Group II (WGII) assesses the vulnerability of socio-economic and natural systems to climate change, negative and positive consequences of climate change, and options for adapting to it and Working Group III (WGIII) assesses options for limiting greenhouse gas emissions and otherwise mitigating climate change. The Task Force on National Greenhouse Gas Inventories is responsible for the IPCC National Greenhouse Gas Inventories Programme.
A little bit of history: the First IPCC Assessment Report was published in 1991 and the Second Assessment Report (SAR), Climate Change 1995, became the background for the negotiations that led to the adoption of the Kyoto Protocol in 1997. The Third Assessment Report (TAR), Climate Change 2001, still serves as a reference work for future assessments. Recently, IPCC agreed to complete its Fourth Assessment Report (AR4) in 2007.
Obviously this is (and needs to be) a very formal and transparent process, open to the public at any stage and closely scrutinized by panels of expert scientists and relevant government employees and policy makers. The present AR4 -WGI process started back in April 2004 when the author teams of the report were selected and the Lead Authors first met in September in Italy to launch the composition of the “zero order draft” which was subsequently submitted to the Technical Support Unit (TSU) for an informal review by invited experts (mostly well-known scientists). In May 2005 the second Lead Author meeting will take place in China to consider comments on the zero order draft and initiate the first order draft writeup. This is why the scientists in Hawaii were ablaze; they have to hurry up and publish their results by the time the first order draft is …drafted.
Later in 2005, the first order draft which was looked at by the TSU must now become available to external reviewers. At this point any scientist in the world can ask to review and comment on the draft. The Third Lead Author meeting will be held in December of 2005 in New Zealand and it will consider comments on the first order draft and initiate the writing of the second order draft. By now all the researchers will have to have their work published in order to be included in the report (talking about tight schedule for our Hawaiian scientists).
By April 2006, the second order draft will be made available to even more external reviewers. Now policymakers and actual Governments can make comments and/or recommendations, so that in June 2006, the fourth Lead Author meeting will evaluate the second order draft, revise it and initiate writing of the final draft to be submitted to TSU and again to Governments for concluding remarks.
Already by January 2007 when the Working Group I Plenary Session of Government representatives will have to approve the Summary for Policymakers line by line and accept the report. (Don’t sweat, it has been done before!)
The scientific part of the final draft of AR4 (WGI) is expected to cover issues such as observations of the state of the atmosphere and the radiative forcing, the ice and sea climate change, paleoclimate, biogeochemistry and evaluations of global and regional model simulations and climate predictions. CMEP and the Hawaiian throngs will mainly contribute to this last part of AR4 and will be a major part of the scientific evidence for climate changes and projections.
So, what is CMEP exactly? Well, it is a very ambitions and painstaking project which has managed to bring together all the aforementioned modeling groups which run specified model experiments with very similar forcings and then performed coordinated diagnostic analyses to evaluate these model simulations and determine the uncertainty in the future climate projections in their models. The output from all the atmosphere-ice-ocean-land coupled general circulation models (GCMs) is hosted in the Lawrence Livermore National Laboratory database. The model variables that are evaluated against all sorts of observations and measurements range from solar radiation and precipitation rates, air and sea surface temperatures, cloud properties and distributions, winds, river runoff, ocean currents, ice cover, albedos, even the maximum soil depth reached by plant roots (seriously!).
Projections for the these variables are given for different model simulations of climate scenarios. What do the models predict for our era if pre-industrial aerosol forcing was kept constant (i.e. no anthropogenic effects)? Or what is the climate going to be if emissions are held at their present-day levels? Other, more sophisticated scenarios were drawn up based on reasonable estimates of what the future world will be like because of decisions and actions governments will/might make (more info).
For instance, the A1 scenario (what unfortunate nomenclature!) considers a future world of very rapid economic growth, low population growth and rapid introduction of new and more efficient technology. Major underlying themes are economic and cultural convergence and capacity building, with a substantial reduction in regional differences in per capita income. In this world, people pursue personal wealth rather than environmental quality. (a …”current-administration”‘s world)
The A2 scenario imagines a very heterogeneous world. The underlying theme is that of strengthening regional cultural identities, with an emphasis on family values and local traditions, high population growth, and less concern for rapid economic development. (an Osmond family world?)
The B1 scenario calls for a convergent world with rapid change in economic structures, “dematerialization” and introduction of clean technologies. The emphasis is on global solutions to environmental and social sustainability, including concerted efforts for rapid technology development, dematerialization of the economy, and improving equity. (a John Lennon going-solo world)
In the B2 scenario, the world places emphasis on local solutions to economic, social, and environmental sustainability. It is again a heterogeneous world with less rapid, and more diverse technological change but a strong emphasis on community initiative and social innovation to find local, rather than global solutions. (a Sting world, for sure).
In Hawaii, reports were made on the interannual and decadal variability, the hydrological cycles of the Tropical Pacific Ocean, the West African and the South-Asian Monsoon, the subantarctic and Antarctic waters, the Arctic Ocean, North American climate changes, changes in surface solar radiation, thermohaline oceanic circulation, midlatitude storms, El-Nino and North Atlantic and Arctic Oscillations. In each case how well these are represented in models was reported along with the range of future projections and their uncertainties.
It was a short, bustling meeting. However, by the end one couldn’t help but wonder what would be in store should any of those alphabetical future climate scenarios actually come to pass…