Fracking = cheap natural gas pulse= unpredicted change in energy sector= challenge to green energy costs and initiatives (wind , solar)= less reliance on oil and coal +cheaper and cleaner electrical generation = reduced carbon emissions

Environmental costs/benefits (fracking and reduced carbon emissions) = unknown
long term outlook for other green initiatives = unknown
long term price/supplies of cheaper natural gas = unknown
future role of coal and oil+ future role (USA) of foreign oil = unknown