How does rising atmospheric CO2 affect marine organisms?

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The Specter of Species Extinction
Will Global Warming Decimate Earth's Biosphere?

Executive Summary


Extinction is forever … and forever is a very long time.  The mere mention of the possibility that CO2-induced global warming could drive species to extinction engages the natural sympathies of people everywhere.  Hence, preventing extinction has become a rallying cry to convince nations to dramatically reduce their CO2 emissions, which are claimed to be responsible for 20th century warming.

It is said, for example, that CO2-induced global warming will be so fast and furious that many species of plants and animals will not be able to migrate towards cooler regions of the planet (poleward in latitude and/or upward in elevation) rapidly enough to avoid extinction.  It is said that the process has already been set in motion by the global warming of the past hundred and fifty years.  It is said, that "a significant impact of global warming is already discernible in animal and plant populations," and that, as a result, "we’re sitting at the edge of a mass extinction."

It is easy to make long-term predictions; but to substantiate them with facts is an entirely different matter.  And even when the facts are largely in hand, one can still be blinded by preconceived ideas that make it difficult to comprehend the real meaning of what has been discovered.  So it is with the specter of species extinction that hovers over the global warming debate.  The vast majority of people who have studied the subject have not understood some of the issue’s most basic elements; and they have consequently drawn conclusions that are not aligned with reality.

Proponents of what we shall call the CO2-induced global warming extinction hypothesis seem to be totally unaware of the fact that atmospheric CO2 enrichment tends to ameliorate the deleterious effects of rising temperatures on earth’s vegetation.  They appear not to know that more CO2 in the air enables plants to grow better at nearly all temperatures, but especially at higher temperatures.  They feign ignorance of the knowledge (or truly do not know) that elevated CO2 boosts the optimum temperature at which plants grow best, and that it raises the upper-limiting temperature above which they experience death, making them much more resistant to heat stress.

The end result of these facts is that if the atmosphere’s temperature and CO2 concentration rise together, plants are able to successfully adapt to the rising temperature, and they experience no ill effects of the warming.  Under such conditions, plants living near the heat-limited boundaries of their ranges do not experience an impetus to migrate poleward or upward towards cooler regions of the globe.  At the other end of the temperature spectrum, however, plants living near the cold-limited boundaries of their ranges are empowered to extend their ranges into areas where the temperature was previously too low for them to survive.  And as they move into those once-forbidden areas, they actually expand their ranges, overlapping the similarly-expanding ranges of other plants and thereby increasing local plant biodiversity.