You are suggesting that we wait a thousand years to record all the data and then suddenly get enviro-conscious. Solubility of gases that are only barely soluble in water is affected by temperatures. This is a proven fact, you don't believe me, take some soda water and heat it up. The gas in soda is carbonate which has a negative charge C03 which makes it more soluble that co2 because it is attracted to the slightly positive Hydrogen of H20, the gas dissolved in the oceans is CO2. Photosynthesis requires CO2, less CO2 dissoved means less photosynthesis, less photosynthesis produces less oxygen. Fish require oxygen, no oxygen means dead fish.