Original sentence: However, emissions of  by human activities are currently more than 130 times greater than the quantity emitted by volcanoes, amounting to about 27 billion tonnes per year
Edited sentence: Emissions of  by human activities are currently more than 130 times greater than the quantity emitted by volcanoes, amounting to about 27 billion tonnes per year.For example, the natural decay of organic material in forests and grasslands, such as dead trees, results in the release of about 220 gigatonnes of carbon dioxide every year.However, carbon dioxide is released to the atmosphere by a variety of natural sources, and over 95% of total  emissions would occur even if humans were not present on Earth.This carbon dioxide alone is over 8 times the amount emitted by humans