A Global Perspective - the Gaia Hypothesis

A Global Perspective

The recognition that, worldwide, civilization can change the environment at a global level is relatively recent. Scientists now believe that emissions of modern chemicals are changing the ozone layer high in the atmosphere. Scientists also believe that burning fossil fuels increases the concentration of greenhouse gases in the atmosphere, which may change Earth's climate. These atmospheric changes suggest that the actions of many groups of peo¬ple at many locations affect the environment of the entire world.

The Gaia Hypothesis

Awareness of the global interactions between life and the environment has led to the development of the Gaia hypothesis, originated by British chemist James Lovelock and American biologist Lynn Margulis. In the early 1970s, James Lovelock theorized that Earth behaves like a superorganism, and this concept developed into what is now known as the Gaia hy¬pothesis. In recent years, the Gaia hypothesis-named for Gaia, the Greek goddess Mother Earth-has become a hotly debated subject. The hypothesis states that life manipulates the environment for the maintenance of life. For example, some scientists believe that algae floating near the surface of the ocean influence rainfall at sea and the carbon dioxide content of the atmosphere, thereby significantly affecting the global climate.

According to James Lovelock, (Gaia hypothesis) Earth is superorganism and compared the cycling of nutrients from soils and rocks in streams and rivers to the circulation of blood in an animal. In this metaphor, the rivers are the arteries and veins, the forests are the lungs, and the oceans are the heart of Earth.

The Gaia hypothesis is really a series of hypotheses:

* The first is that life, since its inception, has greatly affect¬ed the planetary environment. Few scientists would dis¬agree.

* The second hypothesis asserts that life has altered Earth's environment in ways that have allowed life to per¬sist. Certainly, there is some evidence that life has had such an effect on Earth's climate.

* A popularized exten¬sion of the Gaia hypothesis is that life deliberately (con¬sciously) controls the global environment. Few scientists accept this idea

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