Human<span> activities contribute to </span>climate change<span> by </span>causing changes<span> in Earth's atmosphere in the amounts of greenhouse gases, aerosols ,which are small particles, and cloudiness. The largest known contribution comes from the burning of </span><span>fossil fuels,</span><span> which releases carbon dioxide gas to the atmosphere.</span>

now split the equation in half
CH4+O2 I CO2 + 4H2O
C = 1 I C = 1
H = 4 I H = 8
O = 2 I O = 3
CH4+ 2O2 = CO2 + 2H20