The importance of biodiversity was recognised at the 1992 Earth Summit in Rio with a key agreement being the Convention on Biological Diversity. Many biological resources are used in a wide variety of industries, cosmetics, medicines, agriculture to name but a few. There is now a serious decline in the number of species, estimated to be between 5 and 10 million, with extinction rates reaching 1000 times the level of background rates of 0.1 and 1.0 species per million species per year which are (according to Ahmed Djoghla, CBD 2006) due to the intensification of human related activities.
The IUCN confirms that threats to biodiversity are numerous and human activity is responsible for most of them, these being:
- Habitat loss
- Invasive species
- Over exploitation of natural resources
- Pollution and diseases
- Human induced climate change
A study by Sala et al (2000) models changes in biodiversity for the year 2100 and indentifies the ranking of importance of the drivers of change, similar to the list above.
Habitat loss has been exacerbated by changes in land use for agriculture, mineral extraction and human habitation and contributes to deforestation with a net loss of 180 million hectares of forest in developing countries over a period of 15 years (Dodds 2000). Fig 1 below demonstrates the extent of habitat loss and deforestation in Borneo projected to 2020 when it is anticipated that nearly all the forest will have been logged, burnt, and cleared to make way for palm plantations, agriculture and developed for human habitation (Ahlenius UNEP/GRID-Arendal 2007). Environmental regulations in Borneo for example are flouted with corruption playing such a part that it has been described as “symbiotic” (Laurance 2004).
Fig 1: Extent of deforestation in Borneo 1950-2005, and projection towards 2020
Increased land use for agriculture and human habitation causes pollution and disease, in particular with the increased use of man made nitrogen for farming. It is responsible for changing ecosystem balances and leads to the release of nitrogen compounds into the atmosphere which contributes to eutrophication.
Anthropogenic climate change is recognised by the IPCC in their fourth assessment report that it is one of the main threats to life on earth. They conclude that a 2 Deg rise in global temperature from anthropogenic warming would threaten around 30% of all species, with significant extinctions around the global with a 4o rise. With responses to climate change which include mitigation, adaptation and carbon sequestration, fears are growing that biodiversity will become a casualty in the mitigation fight (Paterson et al 2008). Climate change is also said to be responsible for changes in biota physiology, productivity and growth, and changes in species distribution as a consequence of migration with the need to develop predictions how these changes will affect abundance and distribution. (Midgely et al 2002).
Invasive species are perhaps not considered such a threat but when we consider how many species have been transferred either intentionally or unintentionally, as reported by Bax et al (2003) some 10,000 marine species are in transit around the world in ships ballast. In the Fynbos biome in South Africa, invasive species threaten approximately 80% of native species, (Midgley et al 2002). Over exploitation of natural resources, in particular forests, fishing and water can be to some extent controlled by sustainable management otherwise overshoot can occur as forests cannot grow faster than they are felled nor can the replenishment rate of fish meet the rate of harvesting. Water can be withdrawn from aquifers faster than they can be refilled. It is also recognised that oil deposits are laid down over millions of years and at least 1/3rd of all oil has been depleted since the industrial revolution, most of which has been consumed during the past 50 years.
Biodiversity loss is a serious threat to human well being and must be arrested where possible. There is need for more research and understanding of interacting processes and how they fit together. With rising populations, predicted to reach 9 million by 2050, the pressure on the natural world is unlikely to subside in the short term.
References:
- Ahlenius, Hugo UNEP/GRID-Arendal (2007) Extent of deforestation in Borneo 1950-2005, and projection towards 2020, http://maps.grida.no/go/graphic/extent-of-deforestation-in-borneo-1950-2005-and-projection-towards-2020 (accessed 9th November 2010)
- Bax, Nicholas., Williamson, Angela., Aguero, Max., Gonzalez, Exequiel., Geeves, Warren (2003) Marin invasive alien species: a threat to global biodiversity Marine Policy 27, 313-323
- Dodds, Felix (ed) (2000) Earth Summit 2002: A New Deal Published by Earthscan
- Laurance, Willam, F., The perils of payoff: corruption as a threat to global biodiversity Trends in Ecology and Evolution, (2004) Vol. 19, No. 8 399-401
- IPCC, (2007) Climate Change Report 2007: Synthesis Report. Summary for Policy Makers Paterson, James S., Araújo, Miguel B., Berry, Pam M., Piper, Jake M., Rounsevell, Mark D. A. (2008) Mitigation, Adaptation and the Threat to Biodiversity Conservation Biology, Vol. 22, No. 5, 1352-1355
- Sala, Osvaldo E., Chapin III, F. Stuart., Armesto, Juan J., Berlow, Eric., Bloomfield, Janine., Dirzo, Rodolfo., Huber-Sanwald, Elisabeth., Huenneke, Laura F., Jackson, Robert B., Kinzig, Ann., Leemans, Rik., Lodge, David M., Mooney, Harold A., Oesterheld, Martín., LeRoyPoff, N., Sykes, Martin T., Walker, Brian H., Walker, Marilyn., Wall, Diana H. (2000) Global Biodiversity Scenarios for the Year 2100 Science, Vol. 287, 1770-1774
- Secretariat of the Convention on Biological Diversity (2000) Sustaining Life on Earth: How the Convention on Biological Diversity promotes nature and human well being. Published by CDB Montreal
- Secretariat of the Convention on Biological Diversity (2006) Global Biodiversity Outlook 2. Published by CBD Montreal
