"At the dawn of human agriculture 10,000 years ago, the worldwide human population plus their livestock and pets was ~0.1% of the terrestrial vertebrate biomass. Today, it is 98%! (Most of that is cattle.)" He also realized the poignant philosophical ramifications: "Over billions of years, on a unique sphere, chance has painted a thin covering of life—complex, improbable, wonderful and fragile. Suddenly we humans … have grown in population, technology, and intelligence to a position of terrible power: we now wield the paintbrush." Today I saw a deer in my front yard. I did last week too. They keep coming, despite the fact that my neighborhood is surrounded by major roadways. We are beyond encroaching.You may have already calculated it yourself, but this means 99% of all modern humans (technically 99.98%) have lived in the last 10,000 years. Physicist and engineer Paul MacCready eloquently summarized the biological and ecological ramifications of related-statistics in 1999: