section_path: Environmental effects/Climate
section_name: Climate
paragraph_text: Climate
  
  As of 2018, about a quarter of annual global greenhouse gas emissions is the carbon dioxide from burning petroleum (plus methane leaks from the industry). Along with the burning of coal, petroleum combustion is the largest contributor to the increase in atmospheric CO. Atmospheric CO has risen over the last 150 years to current levels of over 415 ppmv, from the 180–300 ppmv of the prior 800 thousand years. The rise in Arctic temperature has reduced the minimum Arctic ice pack to 4,320,000 km (1,670,000 sq mi), a loss of almost half since satellite measurements started in 1979.
  
  Ocean acidification is the increase in the acidity of the Earth's oceans caused by the uptake of carbon dioxide (CO) from the atmosphere.The saturation state of calcium carbonate decreases with the uptake of carbon dioxide in the ocean. This increase in acidity inhibits all marine life—having a greater effect on smaller organisms as well as shelled organisms (see scallops).