The CO2 crisis is about more than global warming

From a pre-industrial-revolution level of 280 parts per million in the atmosphere, carbon dioxide (CO2) has now risen to 400 parts per million. CO2, as the main greenhouse gas emitted by burning fossil fuels, traps infrared radiation, warms the planet, and melts glaciers and ice sheets. People around the world are struggling to cope with rising seas, floods, heat waves, droughts, massive cyclones, tornadoes, and other forms of unstable weather.

Our CO2-rich world is also having negative impacts on saltwater ecosystems. Oceans occupy a large part of the Earth’s surface and are absorbing huge amounts (roughly a third) of our CO2 wastes, far more than land plants and freshwater systems. This waste absorption comes with a price: ocean acidification.

Oceans are naturally mildly alkaline, with a pre-industrial pH of around 8.25. When CO2 dissolves in alkaline waters, it is mostly converted to the bicarbonate form (as noted earlier). This releases hydrogen ions and makes water more acidic. To date, CO2 pollution has decreased ocean pH to around 8.14, which (because pH is measured on a base-10-log scale) represents about a 25 per cent increase in acidity.

Experimental studies indicate that some marine life is particularly affected by acidification: corals that build reefs made of calcium carbonate, and zooplankton and molluscs (e.g. clams, oysters, snails) with shells made of this same compound. Ocean acidification also affects the sensory organs and behaviour of many fish species, especially their juvenile life stages.

The human-caused, rapid rise in CO2 levels from pre-industrial times is having marked effects on terrestrial, freshwater and marine ecosystems. These effects are complex and cannot be as easily grasped by the public as weather disasters, but they are real and worrisome. They add urgency to the need for energy conservation and a transition from fossil fuels to renewable energy sources.

Ole Hendrickson, Rabble. ca, 10 Septembre 2015. Full article.

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