Answer: Over last few decades there is a huge increase in the amount of carbon dioxide in the environment because of various kinds of human activities.
This increase in the level of carbon dioxide has increased the temperature of the earth and has a harmful impact in ocean as it has led to acidification of water.
The amount of carbon dioxide in atmosphere was less in 1980 but has now increased from (1980) 340 ppm to (2000) 370 ppm.