The layman's version of his new paper titled "Earth's Climate History: Implications for Tomorrow" opens with this introduction:
"The past is the key to the future. Contrary to popular belief, climate models are not the principal
basis for assessing human-made climate effects. Our most precise knowledge comes from
Earth's paleoclimate, its ancient climate, and how it responded to past changes of climate
forcings, including atmospheric composition."
That is well and good as far as it goes, but what interests me from the standpoint of one who is concerned about trees dying from air pollution, is a gigantic and critical omission in this approach, for the simple reason that there has NEVER been anything in Earth's history approaching the level of ozone in the troposphere that now exists - and is inexorably rising. When it refers to "past changes of climate forcings, including atmospheric composition", atmospheric composition refers to the level of CO2, and not ozone, because there just wasn't any ozone naturally occurring in the lower atmosphere (with the rare transitory exception of ozone from the stratosphere introduced by lightening strikes). It's a completely untested and dangerous addition created by us in just the past 150 years or so - and there isn't a life form on earth that is suited by evolutionary processes to inhale or absorb its poison.
The rate at which CO2 is accumulating from human activity is unprecedented in past episodes of natural increases, and so that fact alone, as the paper explains, means that the paleoclimate cannot be entirely predictive of how systems will react. But since there is nothing in the past to compare to the human generated emissions of volatile organic compounds from burning fuel, there is also no precedent for trees and other vegetation to be dying en masse in the blink of a geologic eye, or for forests turning from carbon sinks to carbon emitters in a tipping point of such dizzying rapidity that most people are stunned by the vision into blindness.
Of course, even leaving aside the amplifying effect for rising temperatures of dying trees, the paper comes to ominous conclusions based on the insane loss of ice sheet extant and volume...so what difference would it make if people did regain their eyesight and realize that trees are in imminent danger of extinction?
Well, for one thing, like a cancer patient with a terminal prognosis, perhaps we would become sensitive to the ticking clock and do everything possible to wrangle as much time as we could garner. And for another, if it becomes better known that plants - the base of our food chain - are dying out because of air pollution, perhaps the prospect of global famine would be a stronger motivator for drastic conservation, political action, and even a fundamental rethinking of the way society is structured - away from unsustainable growth and towards more just and satisfying and creative cultural priorities.