14 October 2006
Renowned environmentalist Professor Paul Ehrlich spoke at the recent British Association Science Festival of how we are eroding our "natural capital" – in his analogy, humanity is like "a rich kid spending without looking at the bank balance".
Far from living sustainably - when we live from a stable income of natural resources, renewed annually by nature’s cycles - we are now living off "capital", eating away at our very sources of security – soil, water, forest, fisheries etc.
Every year mankind's "borrowing" from nature hits a new record. Last Monday - October 9 - was calculated to be the day when we moved from spending "income" to "capital" for this year. For the remainder of the year, we are eating into our "ecological capital". In releasing their research, the New Economics Foundation noted that this annual day creeps earlier as consumption grows. "Ecological debt day" was on December 19 in 1987 and November 21 in 1995.
Ecological debt day effectively communicates another inconvenient truth. We have come to think of climate change as our greatest problem, and it probably is, but we face other very great dangers from rapid depletion of vital natural resources.
The double whammy is that climate change is set to make these losses happen much faster.
Take fresh water - a vital agricultural resource. We are seeing falling water tables, rivers running dry, and disappearing lakes. Aquifers are being depleted in many countries including the big three grain producers - India, China and the US.
Fossil aquifers are ones that are not connected to ground based water supplies and can not replenished – often the water is hundreds or thousands of years old. Once depleted, farmers can no longer irrigate and have to depend on rainfall to grow low yield crops. Agriculture is lost forever in arid areas such as the south west US.
In the North China Plain, aquifers are dropping at three metres a year and wheat farmers have to pump from depths of more than 300m in some places. China's grain peaked at 392m tonnes in 1998 – a level difficult to regain as irrigation water supplies are depleted.
Last week, Met Office scientists published key new research predicting drought threatening the lives of millions will spread across half the Earth by 2100. As water resources become more depleted, a general "global drying" effect from climate change will reduce supply – a deadly combination.
Disappearing glaciers - reservoirs in the sky – reduce fresh water supplies for huge areas of agriculture and mega city populations eg Calcutta. The massive mountain ranges above the Indian sub-continent – including the Hindu Kush and Himalayas - supply water to half of humanity in Central Asia, South East Asia, India and China.
As the changing climate raises sea levels and lowers water tables, sea water can penetrate into freshwater aquifers causing salination. As water losses and drought increases, these areas have to be abandoned, as there is no supply of fresh water to pump in. And roughly half the world's population lives within 40 miles of the coast.
Or take soil – which another veteran environmentalist Lester Brown calls "the foundation of civilization". Over long stretches of geological time, soil accumulated faster than it eroded, enabling agriculture and the rapid human development of the last few thousand years.
Some time in the 20th century soil erosion started to exceed its formation and now centimeters of soil created over millenniums can be lost in a single decade.
Rich countries saw massive social disruption with the huge soil losses suffered by America and Russia in the dust bowls of the 1930s Great Plains and the 1960s Soviet Virgin lands. Yet few know of the huge dustbowls today that will affect the South much more drastically, although satellite images pick them up easily. In January 2005 NASA picked up a dust storm, 5300km wide, moving out of central Africa. A shocking 2-3bn tonnes of wind-borne soil is estimated to leave central and west Africa each year.
Across Africa and Asia, deserts are advancing, as protective trees and grass are destroyed, and land is overgrazed. Loss of soil and desertification are undermining the basis of civilization, agricultural productivity and food security.
Faced with these harsh realities, rich countries are challenged to learn another way to live. If we look just at our country, 3.1 planets would be required to sustain the world’s population at UK levels of consumption – that is, "UK ecological debt day" is reached around late April.
To start repaying the debt, alternatives to Plan A – business as usual – are needed. Lester Brown's excellent book Plan B 2.0 offers one.