Judging by national and international politics and widespread media coverage, it seems that nowadays everything revolves around climate change and its short- and long-term effects.
Have climate change, vulnerability and adaptation become convenient buzzwords? Is it all commercial hype and economic revamp? Or is there more to climate change from the scientific point of view?
The Intergovernmental Panel on Climate Change (IPCC) is the leading scientific body for the assessment of climate change. It was established by the United Nations Environment Programme and the World Meteorological Organisation to provide the world with a clear scientific view on the current state of climate change and its potential environmental and socio-economic consequences.
The IPCC Fourth Assessment Report, issued in 2007, said warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.
At continental, regional and ocean basin scales, numerous long-term changes in other aspects of climate have also been observed. Trends from 1900 to 2005 have been observed in the amount of rainfall in many large regions.
Over this period, rainfall increased significantly in eastern parts of North and South America, northern Europe and northern and central Asia, whereas rainfall declined in the Sahel, the Mediterranean, southern Africa and parts of southern Asia.
Some extreme weather events have changed in frequency and/or intensity over the past 50 years. It is very likely that cold days, cold nights and frosts have become less frequent over most land areas, while hot days and hot nights have become more frequent.
It is likely that heatwaves have become more frequent over most land areas and that the incidence of floods has increased in many vulnerable areas worldwide since 1975.
In view of the above-mentioned issues, the University of Malta’s Department of Physics decided to embark on regional climate modelling as one of its research priorities, so as to make a valid scientific contribution to help increase the level of understanding of the climate system.
In 2008, the department acquired the licence to operate the regional climate model called Precis (standing for ‘Providing Regional Climates for Impacts Studies’), developed at the Hadley Centre at the UK Meteorological Office.
The department has already acquired significant experience in operating the climate model. In the 2009-10 academic year, three final year B.Sc. (Hons) students opted to do their dissertation in climate studies through the use of this model.
These first studies focussed on continental Europe, the Mediterranean basin and northern Africa, which are areas that offer meteorological challenges. The modelling tools are being used to try to understand further the complex processes affecting the climate in Europe and the Mediterranean region.
The issues being addressed at the moment include the question of the capability of these modelling tools in reproducing past and present climate.
This would enable them to be used with confidence to generate future climate projections. These would then help identify impacts on the economy, demographics and the quality of life of around 880 million people living in these regions of the world.
James Ciarlò, a final year B.Sc. (Hons) student, worked on the validation of the sulfate model within Precis. His work has been very significant, firstly because there is a dearth of scientific knowledge on the modelling of aerosol within climate models, and secondly because aerosols play a significant role in climate dynamics.
The results indicated that the regional climate model we are using over-predicts the sulfate aerosol concentration. Thus, the effects of aerosols on climate, such as reduced rainfall and surface temperature, appear greater in the climate model results.
Precis also considers a very limited number of atmospheric chemical reactions that produce sulfates and, unlike other models, does not consider other aerosols, dust and the ever-important greenhouse gas, carbon dioxide.
Denise Cilia, another final year B.Sc. (Hons) student, subdivided the same study area into four different climate zones and studied them.
In general, the large-scale rainfall (precipitation from Nimbostratus clouds) and surface air temperature were over-predicted, but the intra-variability between the different climate zones was high. However, future climate projection experiments have generated similar results to those published by the IPCC.
Another B.Sc. (Hons) final year student, Nadine Napoli, worked on the vertical variation of various meteorological parameters for the same simulation. The study area was again sub-divided into four regions and the wind-related parameters, in particular wind speed and direction, were studied from the surface up to 20km in the stratosphere.
Seasonal analysis of the wind parameters in the four zones within the study area has revealed a high variability in the model results. This means the large-scale circulation patterns are not being well represented by the regional climate model.
No climate model can claim to be perfect by any means. However, these studies have revealed important and interesting strengths and limitations of Precis.
The motivation to use computer models to better understand the atmosphere, and the increasing sophistication in meteorological measurements, leads to improvements of regional climate models such as the Reg CM4 of the Abdus Salam International Centre for Theoretical Physics (ICTP) in Trieste, Italy.
The department has strengthened its links with the ICTP by participating in several workshops related to climate change over the past two years, and will now be installing the Reg CM4 code on the department’s new supercomputer cluster, which was obtained as a result of a successful grant application for European Regional Development Funds.
In the near future, the department plans to participate in an important international collaboration called Cordex (Coordinated Regional Climate Downscaling Experiment) .
This initiative within the World Climate Research Programme uses high computing power available at different research centres to simulate future regional climates. The department will be contributing by performing computational experiments to simulate future climates in the Mediterranean and the European regions.
The department’s longer-term plans are to help to develop parts of the chemistry module of Reg CM4. In order to be part of this scientific effort, the department needs more physicists, mathematicians, che-mists and software developers through the B.Sc. (Hons) course and related postgraduate courses offered at the University.
The department’s atmospheric physics group hopes more science students become interested in this rapidly evolving area of research, and eventually pursue postgraduate research in order to contribute to the growing body of scientific knowledge on what is arguably one of the most important issues to mankind.
Scientists need to be passionate about their research and need to address important questions, such as those associated with what is happening to the Earth’s dynamics and how humans can adapt to the changes that are being observed.
The public might think climate modelling is somewhat pointless because the results are highly uncertain and thus not useful to policy makers. But if, as proposed, researchers join forces in several worldwide coordinated initiatives to better understand the atmosphere and construct better models, the uncertainties associated with predicting future climates will be reduced.
For further details contact Dr Noel Aquilina at the University’s Department of Physics on e-mail noel.aquilina@um.edu.mt.
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