Global Change, best summarized in its first paragraph: Causes In the past, the main drivers of planetary-scale changes have been solar variation, plate tectonics, volcanism, proliferation and abatement of life, meteorite impact, resource depletion, changes in Earth's orbit around the sun, and changes in the tilt of Earth on its axis. There is overwhelming evidence that now the main driver of the global change is the growing human population's demand for resources; some experts and scientists have described this phenomenon as the anthropocene epoch. In the last 250 years, human-caused change has accelerated and caused climate change, widespread species extinctions, fish-stock collapse, desertification, ocean acidification, ozone depletion, pollution, and other large-scale shifts. Scientists working on the International Geosphere-Biosphere Programme have said that Earth is now operating in a "no analogue" state. Measurements of Earth system processes, past and present, have led to the conclusion that the planet has moved well outside the range of natural variability in the last half million years at least. Homo sapiens have been around for about 300,000 years. Physical evidence Humans have always altered their environment. The advent of agriculture around 10,000 years ago led to a radical change in land use that still continues. But, the relatively small human population had little impact on a global scale until the start of the industrial revolution in 1750. This event, followed by the invention of the Haber-Bosch process in 1909, which allowed large-scale manufacture of fertilizers, led directly to rapid changes to many of the planet's most important physical, chemical and biological processes. The 1950s marked a shift in gear: global change began accelerating. Between 1950 and 2010, the population more than doubled. In that time, rapid expansion of international trade coupled with upsurges in capital flows and new technologies, particularly information and communication technologies, led to national economies becoming more fully integrated. There was a tenfold increase in economic activity and the world's human population became more tightly connected than ever before. The period saw sixfold increases in water use and river damming. About 70 percent of the world's freshwater resource is now used for agriculture. This rises to 90 percent in India and China. Half of the Earth's land surface had now been domesticated. By 2010, urban population, for the first time, exceeded rural population. And there has been a fivefold increase in fertilizer use. Indeed, manufactured reactive nitrogen from fertilizer production and industry