Sentences with phrase «current global human populations»

Several major studies, published today, concur that virtually all current global human populations stem from a single wave of expansion out of Africa.

Not exact matches

A key goal of current research is to predict how these changes will affect global ecosystems and the human population that depends on them.

Thanks for bringing attention to potential global threats to humanity, ones posed by the current huge scale and skyrocketing growth rate of human population numbers on Earth.

«Climate science» as it is used by warmists implies adherence to a set of beliefs: (1) Increasing greenhouse gas concentrations will warm the Earth's surface and atmosphere; (2) Human production of CO2 is producing significant increases in CO2 concentration; (3) The rate of rise of temperature in the 20th and 21st centuries is unprecedented compared to the rates of change of temperature in the previous two millennia and this can only be due to rising greenhouse gas concentrations; (4) The climate of the 19th century was ideal and may be taken as a standard to compare against any current climate; (5) global climate models, while still not perfect, are good enough to indicate that continued use of fossil fuels at projected rates in the 21st century will cause the CO2 concentration to rise to a high level by 2100 (possibly 700 to 900 ppm); (6) The global average temperature under this condition will rise more than 3 °C from the late 19th century ideal; (7) The negative impact on humanity of such a rise will be enormous; (8) The only alternative to such a disaster is to immediately and sharply reduce CO2 emissions (reducing emissions in 2050 by 80 % compared to today's rate) and continue further reductions after 2050; (9) Even with such draconian CO2 reductions, the CO2 concentration is likely to reach at least 450 to 500 ppm by 2100 resulting in significant damage to humanity; (10) Such reductions in CO2 emissions are technically feasible and economically affordable while providing adequate energy to a growing world population that is increasingly industrializing.

These large human impacts on the Earth System must be considered within the context of the large global economic inequality to realize that current levels of resource extraction and throughput only support societies at First World living standards for ∼ 17 % of the world's current population [1].