<P> Ocean acidification is the ongoing decrease in the pH of the Earth 's oceans , caused by the uptake of carbon dioxide ( CO ) from the atmosphere . Seawater is slightly basic ( meaning pH > 7 ) , and ocean acidification involves a shift towards pH - neutral conditions rather than a transition to acidic conditions ( pH < 7 ) . An estimated 30 -- 40 % of the carbon dioxide from human activity released into the atmosphere dissolves into oceans , rivers and lakes . To achieve chemical equilibrium , some of it reacts with the water to form carbonic acid . Some of the resulting carbonic acid molecules dissociate into a bicarbonate ion and a hydrogen ion , thus increasing ocean acidity ( H ion concentration ) . Between 1751 and 1996 , surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14 , representing an increase of almost 35 % in H ion concentration in the world 's oceans . Earth System Models project that , within the last decade , ocean acidity exceeded historical analogues and , in combination with other ocean biogeochemical changes , could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean beginning as early as 2100 . </P>
<P> Ocean acidification is the ongoing decrease in the pH of the Earth 's oceans , caused by the uptake of carbon dioxide ( CO ) from the atmosphere . Seawater is slightly basic ( meaning pH > 7 ) , and ocean acidification involves a shift towards pH - neutral conditions rather than a transition to acidic conditions ( pH < 7 ) . An estimated 30 -- 40 % of the carbon dioxide from human activity released into the atmosphere dissolves into oceans , rivers and lakes . To achieve chemical equilibrium , some of it reacts with the water to form carbonic acid . Some of the resulting carbonic acid molecules dissociate into a bicarbonate ion and a hydrogen ion , thus increasing ocean acidity ( H ion concentration ) . Between 1751 and 1996 , surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14 , representing an increase of almost 35 % in H ion concentration in the world 's oceans . Earth System Models project that , within the last decade , ocean acidity exceeded historical analogues and , in combination with other ocean biogeochemical changes , could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean beginning as early as 2100 . </P>
what is causing the oceans to become more acidic
what is causing the oceans to become more acidic
the uptake of carbon dioxide ( CO ) from the atmosphere
the uptake of carbon dioxide ( CO ) from the atmosphere