|South-East Asia's Environmental Future: The Search for Sustainability (UNU, 1993, 422 pages)|
|Part II - Climatic change and variability|
|7. Enso, drought and flooding rain in south-east Asia|
Soegiarto went on to appeal that much greater attention be paid to unconventional indicators, such as bird behaviour and unusual levels of the sea, and that Third World scientists should be involved in an extensive monitoring network, especially in the critical region of South-East Asia and northern Australia. At present, many significant anomalies go undetected by the remote-sensing and instrumental network, on which prediction principally relies. Nicholls, whose own paper had stressed the use of unconventional data, and of biological responses in particular, welcomed this suggestion which was taken up in discussion as a proposal that should be adopted by the conference as a whole.
The discussion was also extended to correlates with the anomalously wet, anti-ENSO or La Nina events which commonly either precede or follow an El Niño, as described in Nicholls' Chapter 7. James Fox drew attention to stem borer damage in the rice crop, the correlation of which with low dry-season rainfall in East Java was first studied by Van der Laan (1959). This, it seems from subsequent correspondence between Nicholls and Fox, can tentatively be shown to be particularly severe one year after a La Nina event, that is, in a dry year following an unusually wet one.
A similar correlation between the same pairing of rainfall anomalies and low production of sweet potatoes in the highlands of Papua New Guinea was remarked upon by Allen; the wider question of the agricultural significance of this pairing was taken up in a subsequent paper by Brookfield and Allen (1991). At the meeting, Allen stressed the need to pay attention to extremes, rather than averages. Many social systems in the region contain elements which are adaptations to extremes, with continuing institutions that are like ghosts, responsive to extremes in the past.
As is noted in the Introduction to Part II, the anomalous wet season of 1990-1 was followed by a severe and prolonged 1991 dry season in Indonesia, as also in a large part of north-eastern Australia. By August 1991, large forest fires had again broken out in Kalimantan and Sumatra, burning some 30 000 hectares in Kalimantan by October. The rice crop in lava was also seriously affected by the drought.