There is concern, however, that Earth's greenhouse effect may be intensifying because of increased carbon dioxide released into the atmosphere by the burning of fossil fuels.
(Earth's greenhouse effect; may be intensifying; because of increased carbon dioxide) (increased carbon dioxide; released; into the atmosphere; by the burning of fossil fuels)
Earth's greenhouse effect increased carbon dioxide
may be intensifying released
because of increased carbon dioxide
into the atmosphere by the burning of fossil fuels