Explain the Bohr Effect?

CO₂ from respiring tissues diffuses into erythrocytes (red blood cells) where it reacts with water to form carbonic acid (process catalysed by the enzyme carbonic anhydrase). The carbonic acid dissociates into protons and hydrogen-carbonate ions. The increase in protons encourages the oxyhemoglobin to unload its oxygen and increase its uptake of protons, forming haemoglobinic acid and keeping the cells acidity from getting too high. The hydrogen-carbonate ions diffuse out of the erythrocytes into the blood plasma, causing the chloride shift as chloride ions diffuse into the erythrocytes to keep the pH of the cell stable. These changes explain why more oxygen is released from the blood at higher levels of carbon dioxide.