Myth: Human activity only releases a small proportion of CO2

The amount of CO₂ released each year by humans is only about 4 percent of all global emissions. The other 96 percent occurs naturally. So, our impact is very small. 

Fact:

The biosphere does emit and absorb CO₂ all the time. Those two processes cancel each other out, leaving the system in equilibrium. However, the 4 percent emitted by human activity every year has built up over time and now represents 34 percent of all the CO₂ in the atmosphere (up from 280 parts per million in the 1880s to 427 parts per million today). Nature has actually been resisting that increase, by absorbing up to 60 percent of what we’ve been releasing – mainly into the oceans. This process is keeping atmospheric CO₂ levels below where they would otherwise be, but it is increasing ocean acidification significantly. Acidification is having its own detrimental effects on the biosphere, threatening fish species and contributing to coral bleaching.