Temperature rise shifts crop line

Press, 30 August 1989, Page 48

Temperature rise shifts crop line

PA Wellington A rise in temperature world wide has shifted the crop line by as much as 200 km from north to south since industrialisation 100 years ago, a National Climate Centre senior meteorologist, Jim Salinger, says. A graph produced by the centre shows a maximum temperature fluctuation of 2 deg. since records started in 1853. However, the average temperature rise for that period is just oyer 1 deg. — enough to shift crop viability 200 km. Dr Salinger said the present rise in the mean temperature was not alarming in itself, but there was cause for concern when the temperature rise was added to the

increase in greenhouse gases and a rise in sea level.

Greenhouse gases have gone up 50 per cent since industrialisation. While no- one is sure of the effect of this rise, Dr Salinger believes the gases act as an infra-red trap and contribute to a warming of the ocean.

This has meant a rise in sea levels. Over the last 100 years, estimates of that rise are put at between 10cm and 15cm, which has resulted in a considerable loss of productive land.

Dr Salinger said drops in the average yearly temperature have been recorded in the northern hemisphere, possibly caused by increased pollution.