Forests exist in a delicate balance with climate change - sucking carbon dioxide out of the air and hosting biodiversity, as long as droughts, wildfires and ecosystem shifts do not kill them first, a new study reveals.
Forests in some regions experience clear, consistent risks in three areas, but in other regions, the risk profile is less clear, because different approaches to assessing climate risk yield diverging answers.
University of Birmingham researchers joined an international group of experts, led by the University of Utah, to publish their findings today in Science – classifying the three dimensions of risk as:
- Carbon storage: Forests absorb about a quarter of the carbon dioxide that’s emitted into the atmosphere. Research models showed global gains in carbon storage by the end of the century, but experts found higher risk of carbon loss in forests just south of the Arctic and the drier regions of the Amazon and African tropics.
- Biodiversity: The highest risk of ecosystems shifting from one “life zone” to another due to climate change could be found at the current transition between temperate and boreal forests. Results suggested that forests of the boreal regions and western North America faced the greatest risk of biodiversity loss.
- Disturbance: Events like drought, fire or insect damage could kill large areas of forest. Researchers found that boreal forests, again, face high risk under these conditions, as well as the tropics.
If forests are to play an important role in climate mitigation, an enormous scientific effort is needed to better shed light on when and where forests will be resilient to climate change in the 21st century."
Thomas Pugh - Lecturer in Environmental Science, University of Birmingham,
Co-author Thomas Pugh, from the University of Birmingham, commented: “Increasingly, forests are experiencing climates unlike those to which they are used to. This can lead to large losses of trees through disturbances like fire or drought. Forests are adaptable – given time, many will change to be better suited to the conditions. But there is no guarantee that the adapted forests will store the same amount of carbon or support the same levels of biodiversity.
“If forests are to play an important role in climate mitigation, an enormous scientific effort is needed to better shed light on when and where forests will be resilient to climate change in the 21st century. It will be vital to improve models of forest disturbance, studying the resilience of forests after disturbance, and improving large-scale ecosystem models.”
William Anderegg, inaugural director of the University of Utah’s Wilkes Center for Climate Science and Policy led the project to quantify the risk to forests. Researchers had previously attempted to quantify risks to forests using vegetation models, relationships between climate and forest attributes and climate effects on forest loss.
Dr. Anderegg commented: “These dimensions of risk are all important and, in many cases, complementary - capturing different aspects of forests resilience or vulnerability. Large uncertainty in most regions highlights that there's a lot more scientific study that's urgently needed.”
To aid exploration of the results for stakeholders and decision-makers, a visualization tool of the results has been created.
