Approximately seventy percent of carbon dioxide absorbed by the blood will be transported to the lungs

70 per cent of ${\mathrm{CO}}_2$ is transported as bicarbonate ions. About 7 per cent of ${\mathrm{CO}}_2$ is carried in a dissolved state through plasma. About 20-25 per cent of ${\mathrm{CO}}_2$ is carried by haemoglobin as carbamino-haemoglobin.