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Carbon dioxide Sources - Respiration

Respiration, both on land and in the sea, is a key component of the global carbon cycle. On land, an estimated 60 thousand million tonnes of carbon is emitted to the atmosphere each year by autotrophic respiration. A similar amount, about 55 thousand million tonnes, is emitted as a result of heterotrophic respiration.

In the sea, autotrophic respiration is thought to account for about 58 thousand million tonnes of the dissolved inorganic carbon in surface waters each year, with the contribution of heterotrophic respiration being 34 thousand million tonnes.

Human Impact

Though the worldwide human population has now grown above 6 billion, our direct contribution to atmospheric carbon dioxide concentrations via respiration is relatively insignificant. Of more concern is the impact human-induced global warming could have on global respiration rates. As temperatures increase rates of respiration also increase in many organisms, microbes for instance, and there exists a danger of warming inducing further increases in atmospheric carbon dioxide concentrations, and so yet more warming.

Potential for control

Quite obviously, limiting global greenhouse gas emissions and, therefore, future global temperature increases, could help to avoid the spiral of warming, increased respiration rates, and more warming which threatens.

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