Environmental problems – An overview - Environmental Deterioration and Contamination: Problems and their Management - page 32

- Ecosystem changes contributed to substantial net gains in humans' well-being and

economic development. These gains have been achieved at growing cost in the
form of degradation of ecosystem services, higher risks of nonlinear changes and
increasing poverty of some groups of people;

- The challenge of revising the degradation of the ecosystem parallel to keeping or

increasing its services needs significant changes in policies and practices, which are
not currently under way.

The top natural or human-induced factors causing ecosystem deterioration and
biodiversity loss are classified as direct and indirect drivers.
The Millennium Assessment definition of a driver is any natural or human-induced
factor that directly or indirectly causes a change in an ecosystem. The indirect drivers
of change are demographic, economic, sociopolitical, scientific and technological, and
cultural and religious. Direct drivers include climate change, plant nutrient use, land
conversion leading to habitat change, and invasive species and diseases.
Drivers of Change in Ecosystem Condition and Services are explained in detail by
Nelson et al. (2005); some information pertaining to drivers is extracted here:
Direct drivers of ecosystem deterioration:

- Climate variability and change : The temperature has increased in the last century
by 0.6 ◦ C, global average sea-level growth is 0.1-0.2 m. Predicted surface temper-
ature increase is 1.4-5.8 ◦ C for the next century and increasing rate of arid and
semiarid area and more frequent heavy precipitation events and floods;
- Agriculture : Proper nutrient supply to plants is essential for food production; the
amount of nitrogenous fertilizers has increased by eightfold since 1960, while the
amount of phosphorous fertilizers has increased by threefold. Animal agriculture
contributes to methane production significantly. Atmospheric concentrations of
CO 2 have risen by about 30% and methane concentrations have doubled since
preindustrial times;

- Land conversion, land use changes , deforestation and forest degradation amount-

ing to 8.5%, degradation of arid and semiarid areas by 10%. About 30% of the
earth's surface is cropped, and a further 10-20% increase is forecasted;

- Biological invasion and diseases causing the extinction of native species and loss

in ecosystem services. However, some invaders are beneficial for human economy
and society.

Indirect drivers of ecosystem deterioration:

- Demographic drivers : 6 billion people in 2000, 7 billion in 2011, 1.5% yearly
growth, 10 billion predicted for 2100;

- Economic drivers (consumption, production and globalization): income growth

rate was 2.1% between 1950 and 2000;

- Sociopolitical and religious as well as scientific and technological drivers : Improper

policies, subsidies, selfish ethics, and conventional deteriorating technologies
cause ecosystem deterioration as has happened in the past and as is happen-
ing in the present. Newly developed species with high yield and other beneficial