Of these, the major one is carbon dioxide which accounts for six times more global warming than the other GHGs combined. Carbon dioxide is emitted into the atmosphere when we burn fossil fuels such as coal, oil, and natural gas. We also increase the amount of carbon dioxide through deforestation. Trees and other plants absorb carbon dioxide during photosynthesis. When a forest is cut, not only will carbon dioxide be released if we burn the wood for cooking or heat or allow it to decay and decompose but we also have eliminated a major carbon sink. The amount of CO2 in the atmosphere was 280 ppm in the 1750’s. In 2013 it was 396 ppm, the largest it has been in 800,000 years! As for the others, methane, whose levels in the atmosphere have doubled since 1750, is released during energy extraction operations and rice production, by livestock as a metabolic waste product and when organic matter in landfills decompose. Nitrous oxide, up by 20% since 1750, is a by-product of feedlots, chemical manufacturing plants, auto emissions, and synthetic nitrogen fertilizers and tropospheric ozone, which has increased 36%, comes about when automobile exhaust emissions react with sunlight. (Withgott & Laposata, …show more content…
First, as the planet warms, mountaintop glaciers, which supply water in the summer for 1/6th of the world’s population, are disappearing which will force millions of people to search for another source of water or move. Second, as temperatures increase, sea levels will rise due to runoff from melting artic glaciers and warmer ocean water expanding in volume. Such rising sea levels will lead to beach erosion, flooding of coasts where over half of the U.S. population resides, and intrusion of salt water into aquifers. Third, rising temperatures may impact the Earth’s biodiversity. Warming ocean waters, for example, are contributing to the bleaching of coral reefs. Animals and plants whose habitats are high on mountaintops will be forced to move upward until there is nowhere that they can go leading to their extinction. Also, rare species that we protect in reserves will need to leave those reserves when their habitat changes. In addition, forests and other ecosystems may be subject to invasive species who move in from more southern areas as their habitat gets too warm for them. This latter point leads to a fourth probable impact of global warming and that is negative impacts to human health. People living in temperate zones will be subject to more diseases as mosquitos