For four decades UC San Diego atmospheric scientist Veerabhadran “Ram” Ramanathan has warned that carbon dioxide and other emissions from human activity are heating up the planet. One of the first scientists to predict global warming, his models of rising temperatures have proved remarkably accurate.

Ramanathan prefers the term “climate disruption” to climate change because it more accurately describes the severity of what we are observing.

“Drought, heat waves, forest fires — we are already seeing this,” he says.