Why Ecosystems Collapse

* The world’s natural resource depletion is currently escalating “at a rate unprecedented in human history”. Growth in demand for raw materials, food and energy is having a devastating impact on the earth’s ability to sustain natural biodiversity and clean air

* Current global consumption levels have result in a large-scale ecosystem collapse, since more food is needed by living creations on the small available resources on the ecosystem

* Biodiversity suffers when the planet’s biocapacity cannot keep pace with human consumption and waste generation.

* Humanity is no longer living off nature’s interest, but drawing down its capital. This growing pressure on ecosystems is causing habitat destruction or degradation and permanent loss of productivity, threatening both biodiversity and human well-being

* The biodiversity loss was a result of resources being consumed faster than the planet could replace them

* Populations of species in terrestrial, marine and freshwater ecosystems have declined by more than 30% since 1970, In the tropics the declines are even more dramatic, as natural resources are being intensively exploited for human use.

* Overfishing is a problem why ecosystem collapse, because if one fish is gone then the fish above it in the food chain won’t be able to eat that fish and it will mess up the food chain, thus degrading the system.

* It warned that if demand continued at the current rate, two planets would be needed to meet global demand by 2050.

The health of an ecosystem can, to a large extent, be judged by its level of biodiversity. While biodiversity is often thought of as the number of distinct organisms residing within an ecosystem - to understand the true role of ecosystem biodiversity we must look at the connections that exist between these organisms. An ecosystem is like a complex web of mutually beneficial relationships whereby each organism not only utilizes other parts of the ecosystem for its own preservation but its very existence contributes to the existence of other organisms in the relationship. Through this understanding of biodiversity we see the role of mutual dependency - the more connections that exist within an ecosystem the more resilient that ecosystem is to environmental change.

The concept of ecosystem collapse, then, enters in at a point in history where we have seen dramatic reductions in the level of earth’s biodiversity; and thus this relates to the health of ecosystems worldwide. In the United States alone we see 95% of all old growth forest now gone (through deforestation) & 99% of all native prairie also gone. Global fish stocks in the world’s oceans have been depleted to a dangerously unsustainable level - at current rates global fish stocks will have been depleted to an irrecoverable level before the end of the century. While these types of reductions are often viewed on a global scale, to understand their true affects we must examine ecosystems more locally.

Phenomenons such as eutrophication or the introduction of hazardous chemicals into an ecosystem can be massive points of stress in a localized ecosystem. These types of reductions of earth’s biodiversity have dramatic affects on the health of ecosystems. As reported by the Environmental News Network in 2001 this type of slow reduction of biodiversity within an ecosystem - this reducing of mutually supportive bonds between organisms can reach a point of breakdown or collapse (http://news.nationalgeographic.com/news/2001/08/0807_ecollapse.html).  In ecosystem collapse the bonds between organisms have been stressed to a point of such precariousness that “even the slightest disturbance can make them collapse” (Marten Scheffer, University of Wageningen). "Gradual changes in vulnerability accumulate and eventually you get a shock to the system, a flood or a drought, and boom, you're over into another regime. It becomes a self-sustaining collapse." (Stephen Carpenter, University of Wisconsin-Madison).

A poignant example of ecosystem collapse is the development of dead zones around the world. Even before the BP oil spill in the Gulf of Mexico a vast area within the gulf was unable to support life for several months a year. The collapse of this ecosystem and creation of a dead zone is caused primarily from agricultural runoff of nitrates flowing into the Mississippi. Nitrates in the gulf then cause massive algae blooms - effectively sucking all of the oxygen out of the gulf and depriving it of life for months on end. Without oxygen the variety of organisms and web of relations within gulf ecosystem collapses causing a dead zone.

A critical concept related to ecosystem collapse is carrying capacity - the level of life that an ecosystem can sustainably support. Reductions to an ecosystem’s carrying capacity that lead to collapse often are caused by a disastrous event occurring on a relatively short time line. Considering the millions of years required to develop the degree of biodiversity here on earth, might the unprecedented changes made by humans in the last century as a result of the industrial revolution lead to a global ecological collapse?

Scientists argue that just as depletion of biodiversity can lead to collapse, ecosystems often rebound given sufficient resiliency. Augmentation of ecosystem biodiversity may indeed have opposite affects to its depletion. Alan Weisman describes in his book The World Without Us ecosystems that have been allowed to undergo this process. On the island of Crete in the Mediterranean an area of land prohibited to access by humans has rebounded with astounding speed - quite thoroughly reestablishing its level of biodiversity. These are the stakes. What are we as global citizens to do about it?