With their enormous size and weight, today's farm machines have significant downsides: they compact the soil, reducing porosity and killing beneficial life, meaning crops don't grow so well.
Yet it becomes a striking departure from the historical norm when you look back and find that profits last hit such a lofty percentage of GDP more than 50 years ago and dropped shortly thereafter.
In a study published in the journal Ambio, scientists found that lead levels in soil in the North-eastern United States had decreased markedly since the introduction of unleaded gasoline.
In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.
Evidence from other studies suggests that exclusion of fire results in markedly decreased plant-species richness, often with an increase in tree density.
In the past two decades, however, continued connection with and dependence on family, thanks to cell phones, email and social media, have increased significantly.
Similarly with earnings, young men's wages (after adjusting for inflation) have been on a downward trajectory since 1970 and fell significantly from 2000 to 2010.