Environmental effects

The presence of oil has significant social and environmental impacts, from accidents and routine activities such as seismic exploration, drilling, and generation of polluting wastes not produced by other alternative energies.

Extraction
Oil extraction is costly and sometimes environmentally damaging, although Dr. John Hunt of the Woods Hole Oceanographic Institution pointed out in a 1981 paper that over 70% of the reserves in the world are associated with visible macroseepages, and many oil fields are found due to natural leaks. Offshore exploration and extraction of oil disturbs the surrounding marine environment. [16] But at the same time, offshore oil platforms also form micro-habitats for marine creatures. Extraction may involve dredging, which stirs up the seabed, killing the sea plants that marine creatures need to survive.

Oil spills

Volunteers cleaning up the aftermath of the Prestige oil spill
Crude oil and refined fuel spills from tanker ship accidents have damaged natural ecosystems in Alaska, the Galapagos Islands, France and many other places and times in Spain (i.e. Ibiza).
The quantity of oil spilled during accidents has ranged from a few hundred tons to several hundred thousand tons (Atlantic Empress, Amoco Cadiz...). Smaller spills have already proven to have a great impact on ecosystems, such as the Exxon Valdez oil spill

Global warming
Main article: Global warming
Burning oil releases carbon dioxide into the atmosphere, which contributes to global warming. Per energy unit, oil produces less CO2 than coal, but more than natural gas. However, oil's unique role as a transportation fuel makes reducing its CO2 emissions a particularly thorny problem; amelioration strategies such as carbon sequestering are generally geared for large power plants, not individual vehicles.

Whales
It has been argued that the advent of petroleum-refined kerosene saved the great cetaceans from extinction by providing a cheap substitute for whale oil, thus eliminating the economic imperative for whaling