A new study co-authored by Assistant Professor of Biology Sydne Record casts serious doubt on a widely held opinion that climate change may promote greater growth in many northern forests, which might lead to increased absorption of carbon dioxide and a dampening of climate change.
“This study is important as our results suggest that society may not be able to confidently rely on northern forests to mitigate carbon dioxide emissions.,” Record says. “This finding has implications for calculating global carbon stocks and international agreements on carbon dioxide emissions.”
The study, which was led by a team from the University of Arizona, combines future climate model projections, historic tree-ring records across the entire continent of North America, and how the growth rates of trees may respond to a higher concentration of carbon dioxide in the atmosphere.
Published in the journal Ecology Letters, the study is the first to reveal the possible impact of a changing climate on the growth rate of trees across all of North America. In other words, how their growth changes over time and in response to shifting environmental conditions. The results are detailed forecast maps for the entire North American continent that reveal how forest growth will be impacted by climate change.
The team was startled to find no evidence for a greenhouse-gas absorbing process called the boreal greening effect in their simulations. Boreal greening refers to the assumption that trees in high latitudes, where colder temperatures limit growth, should benefit from warmer temperatures and higher concentrations of carbon dioxide in the atmosphere and, as a result, "green" under the effects of climate change. In turn, these thriving boreal forests should be able to scrub more carbon dioxide from the atmosphere, so goes the idea, dampening climate change.
The Record Lab at Bryn Mawr uses computational methods to understand the past, present, and future states of the natural world to better understand the services that ecosystems afford to society. Record contributed to this study by helping to think through the analysis, framing, and writing of the manuscript.
This article uses material from the University of Arizona press release announcing the results of the study.
An abstract of the research paper, "Observed forest sensitivity to climate implies large changes in 21st century North American forest growth," is available here: http://doi.wiley.com/10.1111/ele.12650 .