As long as climate change doesn’t kill them first with its droughts, wildfires, and changes to ecosystems, forests are in a delicate, deadly dance with climate change. They are pulling carbon dioxide out of the air with billions of leafy straws and giving life to a lot of different things.
In a study that was recently published in Science, William Anderegg, the first director of the Wilkes Center for Climate Science and Policy at the University of Utah, and colleagues quantified the risk that climate change poses to forests along three dimensions: carbon storage, biodiversity, and loss of forest due to disturbances like fire or drought. The findings indicate that forests in particular regions are subject to distinct and consistent threats. In other places, the risk profile is less clear because different methods that look at different parts of climate risk give different results.
“The fact that most places have a lot of uncertainty shows how important it is to do a lot more scientific research,” says Anderegg.
An international team
Researchers from the United Kingdom, Germany, Portugal, and Sweden were included in Anderegg’s team.
He claims to have met some of these individuals and to have read many of their articles.I got in touch with them to see if they were interested in contributing their knowledge and data to a huge, synthetic analysis like this.
Assessing climate hazards to the world’s forests, which cover all continents and climates, support incredible biodiversity, and store enormous amounts of carbon, was a difficult challenge for them. Researchers have tried to estimate the dangers to forests in the past by using vegetation models, correlations between climate and forest features, and the effects of climate on forest loss.
The team claims that while each strategy “has various intrinsic strengths and shortcomings,” a worldwide synthesis of approaches is still absent. Each of the previous methods—carbon storage, biodiversity, and danger of forest loss—examined a particular aspect of climate risk. The group targeted each of the three in their latest analysis.
Three dimensions of risk
“All of these risk factors are significant and frequently work in tandem. They demonstrate many facets of a forest’s resilience or vulnerability, “says Anderegg.
Carbon storage: Forests play an important role in protecting the earth from the effects of rising atmospheric carbon dioxide by absorbing approximately one-quarter of the carbon dioxide released into the atmosphere.The team used the output from numerous different vegetation and climate models to simulate how various plant and tree kinds respond to various climatic conditions. The climates of the recent past (1995–2014) and the end of the 21st century (2081–2099), in both high and low carbon emission scenarios, were then compared.
By the end of the century, the models predicted increased carbon storage on a worldwide scale, despite significant differences and uncertainty across the various climate-vegetation models. The researchers discovered a higher risk of carbon loss in southern boreal forests, which are located just south of the Arctic, as well as the drier areas of the Amazon and African tropics, when they zoomed in on regional forests and took into account models that predict carbon loss and changes in vegetation.
Unsurprisingly, the researchers discovered that the biome boundaries, such as the existing boundary between temperate and boreal woods, are where ecosystems are most at danger of moving from one “life zone” to another as a result of climate change. Since the models used by the researchers showed changes in ecosystems as a whole rather than changes in individual species, the results showed that forests in the boreal regions and western North America had the highest risk of biodiversity loss.
The probability of “stand-replacing disturbances,” or occurrences like drought, fire, or insect damage that might obliterate large tracts of forest, was the last factor examined by the authors. The researchers then used future temperatures and precipitation projections to forecast into the future and observe stand-replacing disturbances between 2002 and 2014 to determine how frequently these events would occur in the future. Under these circumstances, both the tropics and the boreal forests are at significant risk.
According to Anderegg, forests “store an enormous quantity of carbon and delay the speed of climate change.” “The great bulk of the biodiversity on Earth is found there. Additionally, they may be highly susceptible to calamities like major fires or droughts. Thus, when thinking about the future of Earth’s forests in a fast-changing climate, it’s vital to take into account each of these features and dimensions.
Future needs
Anderegg was surprised that the high-risk spatial patterns didn’t cover more of the dimensions. He says they wouldn’t likely be identical because they “catch various parts of forests’ responses,” but he did expect some similar patterns and correlations.
According to the researchers, models can only be as accurate as the foundation of scientific knowledge and data on which they are based. This analysis reveals important knowledge and data gaps that could be a factor in the uneven results. For instance, global models of biodiversity do not include the dynamics of growth and mortality or the direct consequences of rising CO2 on species. Additionally, regrowth or species turnover are not included in models of forest disturbance.
A tremendous scientific effort is required, the authors write, “to better shed light on when and where forests will be resilient to climate change in the 21st century,” if forests are to be tapped to play a significant role in climate mitigation.
According to Anderegg, enhancing large-scale ecological models, researching how resilient forests are after disturbance, and enhancing models of forest disturbance are crucial next steps.
Decision-makers in the US and throughout the world may now access cutting-edge science and tools thanks to the University of Utah’s recently opened Wilkes Center for Climate Science and Policy. To enable this study, the authors created a tool for stakeholders and decision-makers to visualize the results.
The results are ambiguous, but western North America appears to continuously have a significant risk to forests. He asserts that action is necessary to preserve these forests.
The first thing we must understand, according to Anderegg, is that the risks in the West will decrease the sooner we address climate change. We may begin to plan for rising risk and manage forests to lower risk, like fires, in the second place.
