Get flash to fully experience Pearltrees
Graph of human population from 10,000 BC – 2,000 AD Areas of high population densities, calculated in 1994. Human population growth rate in percent, with the variables of births, deaths, immigration, and emigration – 2011
Key A population is all the organisms of the same group or species who live in the same geographical area and are capable of interbreeding. [ 1 ] [ 2 ] In ecology the population of a certain species in a certain area is estimated using the Lincoln Index . The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals from other areas. Normally breeding is substantially more common within the area than across the border. [ 3 ] In sociology , population refers to a collection of human beings.
Natural gas has been touted as a "bridge" from high-carbon sources of energy like coal and oil to a renewable energy future. This assumes sufficient quantity of natural gas from previously inaccessible shale gas deposits to be accessed by horizontal drilling and hydraulic fracturing. Without shale gas, U.S. domestic gas production is projected to fall by 20% through 2035, according to a review of the latest outlook (2011) of the U.S. Energy Information Administration (EIA).