TUHO: (nesouvisi sice se zmenami klimatu, ale snad mi odpustite)
Over the relatively short span of human history, major innovations, such as the domestication of livestock, adoption of an agricultural lifestyle, and the Industrial Revolution, have increased the human population dramatically and have had radical ecological effects. Today, the biomass of humans (≈0.06 Gt C; SI Appendix, Table S9) and the biomass of livestock (≈0.1 Gt C, dominated by cattle and pigs; SI Appendix, Table S10) far surpass that of wild mammals, which has a mass of ≈0.007 Gt C (SI Appendix, Table S11). This is also true for wild and domesticated birds, for which the biomass of domesticated poultry (≈0.005 Gt C, dominated by chickens) is about threefold higher than that of wild birds (≈0.002 Gt C; SI Appendix, Table S12). In fact, humans and livestock outweigh all vertebrates combined, with the exception of fish. Even though humans and livestock dominate mammalian biomass, they are a small fraction of the ≈2 Gt C of animal biomass, which primarily comprises arthropods (≈1 Gt C; SI Appendix, Tables S13 and S14), followed by fish (≈0.7 Gt C; SI Appendix, Table S15). Comparison of current global biomass with prehuman values (which are very difficult to estimate accurately) demonstrates the impact of humans on the biosphere. Human activity contributed to the Quaternary Megafauna Extinction between ≈50,000 and ≈3,000 y ago, which claimed around half of the large (>40 kg) land mammal species (30). The biomass of wild land mammals before this period of extinction was estimated by Barnosky (30) at ≈0.02 Gt C. The present-day biomass of wild land mammals is approximately sevenfold lower, at ≈0.003 Gt C (SI Appendix, Pre-human Biomass and Chordates and Table S11). Intense whaling and exploitation of other marine mammals have resulted in an approximately fivefold decrease in marine mammal global biomass [from ≈0.02 Gt C to ≈0.004 Gt C (31)]. While the total biomass of wild mammals (both marine and terrestrial) decreased by a factor of ≈6, the total mass of mammals increased approximately fourfold from ≈0.04 Gt C to ≈0.17 Gt C due to the vast increase of the biomass of humanity and its associated livestock. Human activity has also impacted global vertebrate stocks, with a decrease of ≈0.1 Gt C in total fish biomass, an amount similar to the remaining total biomass in fisheries and to the gain in the total mammalian biomass due to livestock husbandry (SI Appendix, Pre-human Biomass). The impact of human civilization on global biomass has not been limited to mammals but has also profoundly reshaped the total quantity of carbon sequestered by plants. A worldwide census of the total number of trees (32), as well as a comparison of actual and potential plant biomass (17), has suggested that the total plant biomass (and, by proxy, the total biomass on Earth) has declined approximately twofold relative to its value before the start of human civilization. The total biomass of crops cultivated by humans is estimated at ≈10 Gt C, which accounts for only ≈2% of the extant total plant biomass (17).