Op-Ed: With climate change, we may witness sequoia forests convert to chaparral
What will happen if global warming causes a mass die-off of long-lived, slow-growing coniferous trees such as the famed Douglas-fir or the majestic Sequoia? Will they eventually become part of a shrubby desert, as the scientists speculate?
It’s a question that has bedeviled climatologists for decades in the aftermath of the 1986 eruption of Mount Pinatubo in the Philippines, which significantly increased the level of CO2 in the atmosphere and triggered catastrophic forest mortality (it’s still ongoing).
The Pinatubo effect is believed to have also played some role in the demise of the whitebark pine outside of the Pacific Northwest.
A new study co-authored by University of Arizona climate scientist Roger A. Pielke, Jr., suggests that a similar fate could befall the world’s most iconic tree species, the sequoia.
Pielke and colleagues have published a paper in the journal Nature, detailing a study of sequoia-scale simulations in the Intergovernmental Panel on Climate Change’s Special Report on Global Warming of 1.5°C.
“We find that [long-term changes in the world’s tropical forests] will be more disruptive than global warming itself because the Pinatubo-like aerosol forcing (increases in aerosols that block or weaken the sun’s rays) is far more disruptive than global warming,” Pielke told Climate Central.
But, as is the case with climate changes in general, the Pinatubo-like aerosol forcing will likely play only a limited role in the future, according to Pielke.
“In general, we believe that the Pinatubo aerosol forcing will be one of many climate forcing that cause forest mortality as in the Pinatubo example,” Pielke said.
Aerosol forcing is the term used to describe the effect that increased levels of greenhouse gases in the atmosphere would have on the Earth’s atmosphere.
If levels of greenhouse gases rise because the “greenhouse effect,” the world’s average temperatures will rise until they�