Why might people look for alternatives to fossil fuel?

Which layers form earths rigid mobile tectonic plates? Can an element be broken down in a simpler substance? How do absorb H2O? What is the attraction between hydrogen and oxygen atoms in a water compound called? What state in the us has long cold winters and short warm summers? How hydrogen and oxygen is separated from water? What is 35.6 Celsius? How many valance electrons does phosphorus have? A limestone that contains fossils would be classified as what type of sedimentary rock? What is brown spot under nose after cauterization? This metal is very reactive has properties to those of magnesium and same period as bromine? What are the similarities and differences between Earths early environment? Is the Earth heated from the top or from the bottom? How do scientists classify mountains? What is the process in which layer upon layer of sediment builds up and pressure from the upper layers causes the lower layers to stick together and form solid rock? Is it true that because of the rotation of the earth surface currents in northern hemisphere bend to the right? What are the three criteria used to classify the different types of mass wasting? What is the equation of magnesium nitrate with an excess of sodium phosphate to make sodium nitrate and magnesium phosphate.? What color does Magnesium chloride burn? Small mound formed by the deposit of rocks from a melting glacier?

Why might people look for alternatives to fossil fuel?