Robyn Williams: Professor Tom Crowther. And he gave those figures on the potential of trees earlier in his press conference. We need 1.2 trillion more. Just as so many of them in America have been demolished in a holocaust of fire, as Dr Reese Halter reports.
Reese Halter: In California we've just come through two back-to-back years of record-setting bushfires, including the Camp fire, the single most deadly and destructive inferno on record, which killed at least 86 people in October of 2018. Last year in California we also saw a different kind of firestorm erupt amidst high temperatures and very low humidity. The Carr fire quadrupled in size within days. Huge, towering plumes of hot smoke created wicked updraughts visible seven miles above the Earth.
These plume-driven fires rotate quickly and resemble apocalyptic tornadoes; full-on rotating convective columns. Scary as hell. They're known as fire vortices, or firenadoes. The Carr fire updraughts were so intense that they stripped leaves off mature trees and wrenched whole trees out of the earth. My colleagues estimated that the winds were in excess of 240 kilometres per hour.
As if California's bushfires weren't heartbreaking enough, last year an additional 18.5 million mature trees died from prolonged heatwaves, dehydration, and indigenous beetle infestations. Since 2010, 147 million mature trees have expired in California. It's a toll not seen in modern times. This much we do know: we cannot live without trees. It's a stark wakeup call and it's evident all across America, where another 180 million mature urban trees are dead. Elsewhere there are massive forest graveyards on all continents.
It's time to reduce fossil fuel emissions, end annual subsidies of 5.3 trillion dollars for fossil fuel companies forthwith. We need to mobilise all industries within 197 countries, dovetailing them towards attaining a zero-combustion world economy post-haste. We're facing an unprecedented global emergency. To survive, it's going to take everything we've got. For The Science Show, from Los Angeles, California, I'm Reese Halter.
Robyn Williams: Who did a PhD on forestry, in Melbourne.