Assertion: carbon tetrachloride's concentration | /r/CapableOf | increase to 390 ppm
Facets:
value: in 2013
type: TEMPORAL
value: due to human activities
type: CAUSE
Source sentences:
text: About 2 decades ago, the natural concentration of CO 2 in the Earth’s atmosphere was around 280 ppm and has increased to 390 ppm (in 2013) due to human activities, such as burning of fossil fuels with oxygen.