.. in the 20th century, physicists began to grapple with the kinds of complex systems that can’t be stripped down in the usual way. In these systems — such as Earth’s climate — small details matter; they can snowball and effect sweeping changes, in a process called a positive feedback loop. New methods had to be developed to identify the operating principles behind these complex, chaotic systems, and approximate their behavior. It’s this pioneering work on distilling complexity that has been honored by today’s Nobel Prize in physics.