Over the whole planet, there will be a threefold increase in the average acidity of the oceans, which is unprecedented during the past 20 million years.

在整个地球，海洋平均酸度将增加三倍，这是在过去两千万年里从未发生过的。

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Scientists estimate that the average acidity of surface ocean waters worldwide is now about 30% higher than before the Industrial Revolution.

BBC: Arctic Ocean 'acidifying rapidly'