Palaeoclimates and their modelling: With special reference to the Mesozoic ERA, J. R. L. Allen, B. J. Hoskins, B. W. Sellwood, R. A. Spicer & P. J. Valdes (eds). Chapman & Hall (London), 1994. No. of pages: ix + 140 pp. Price: £35.00. ISBN 0–41256–330–4
✍ Scribed by J. A. Crame
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 216 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0899-8418
No coin nor oath required. For personal study only.
✦ Synopsis
Ever since the development of powerful numerical climate models, there has been an understandable interest in applying them to the geological record. If we regard the slower changing components of a climate system as essentially fixed boundary conditions, it should then be possible to monitor the faster changing ones at various snapshots in time within the past. To date, most of this sort of work has been focused on what many earth scientists would call the 'recent' past; the last 1 million years or so. However, what if we went back further, as some have suggested, perhaps tens, or even hundreds, of millions of years? As the positions of continents and oceans can now be fixed with a considerable degree of accuracy for many of the classic geological periods, could we not begin to model climates on an ancient, pre-glacial Earth?
Such was the theme of a recent Royal Society Discussion Meeting, the results of which are presented in this book. Recent interest in Jurassic climates has been sparked not just by Steven Spielberg, but also by the publication of three contrasting general circulation models GCMs for the period. P. Valdes reviews one of these, the UGAMP model, which is a derivative of a well-known high-resolution weather forecasting model. Using a fine-resolution grid he has plotted the latest computer reconstruction of continental outlines, estimated orography from general plate tectonic considerations, and set other boundary conditions, such as solar and orbital constraints, as for today, but CO, concentration at four times present levels. The resultant model, for the Kimmeridgian Stage (1 52-1 54 million years ago), gives a comparatively high global annual temperature value (20.1"C), and only very restricted areas of subfreezing temperatures. Such results accord well with the geological and palaeontological evidence for the Late Jurassic period, as summarized by B. W. Sellwood and G. D. Price,