World population is already nearly 4 billion more than the 2 billion the planet can comfortably sustain, according to an ecological study of natural resources to be published later this year.
Fertile soil for growing crops, unpolluted water, fossil fuels and the flora and fauna on which humanity depends are all being depleted at a rate that will lead to catastrophic natural, social and political disasters by the end of the next century, a leading ecologist told the meeting.
David Pimentel, professor of ecology at Cornell University at Ithaca, New York, released the results of a year-long study into the optimum human population - the number of people the planet can comfortably support with a reasonable standard of living for all.
The study concludes the present population of 5.6 billion will have to shrink to 2 billion. However, the projected population for 2100 is expected to be between 12 and 15 billion.
Professor Pimentel acknowledged that drastic adjustments to cut the population to 2 billion will cause serious difficulties. 'But continued rapid population growth will result in even more severe, social, economic and political conflicts - plus catastrophic public health and environmental problems.'
Among the main findings of the Cornell study are:
Soil erosion is more intense than ever. It takes about 500 years for an inch of topsoil to form, yet intensive farming is leading to topsoil being lost between 20 and 40 times faster than it is being replaced.
Global food production, which has increased over the past few decades, is to fall by about 20 per cent over the next 25 years.
Fresh water supplies will come under increasing strain, with demand expected to double because of a 20 per cent increase in human numbers.
Fossil fuels will be all but depleted within the next century. If all the people in the world consumed energy at the rate of a typical US citizen, the world's fossil fuel reserves would last a mere 20 years.
The world is losing 150 species of animals and plants a day because of human activities. This threatens the 500,000 species of animals, plants and microbes that carry out essential functions for humans, such as crop pollination and purifying water and soil.
The ecologists say: 'To do nothing to control population numbers is to condemn future humans to a lifetime of absolute poverty, suffering, starvation, disease and associated violent conflicts.'Reuse content