Researchers at Oregon State University have found that the chronic drought that struck western North America from 2000 to 2004 was the strongest in 800 years, but predict that such drought conditions may become the 'new normal' in coming decades.
In a study published in Nature Geoscience, a group of ten researchers found that the prolonged drought cut carbon sequestration by 51 percent in a huge tract of western North America. The drought caused vegetation to whither, releasing carbon dioxide into the atmosphere and accelerating global warming as a result.
The multi-year drought from 2000 to 2004 was unlike any drought in centuries, according to tree-ring data. However, climate models suggest that the precipitation patterns that led to this severe drought are likely to persist far into the future.
In a somber conclusion, the scientists suggest that 'towards the latter half of the 21st century the precipitation regime associated with the turn of the century drought will represent an outlier of extreme wetness.'
Permanent shifts in precipitation patterns pose a threat to BC's forests. Forests act as a carbon sink, storing carbon above and below ground, so climate-induced tree mortality has the potential to release huge volumes of stored carbon.
In their study, the Oregon State University researchers estimate that 'the present mid-latitude carbon sink in western North America could disappear by the end of the century.'
Scientists and policymakers are aware of the threat, and are acting accordingly. In BC, researchers are looking to develop drought-resilient forests by identifying trees that are genetically predisposed to drought-hardiness. (See related GLOBE-Net article: Weather shifts have strong implications on forest management and carbon in BC: UBC.)
Forest managers are considering future climate conditions and are planting trees that can survive the climate of fifty or a hundred years from now. When forests are managed for carbon, the uncertainty of climate change is addressed by placing generous buffers on forest carbon credits.
The risk of climate change to forests is severe. But through modelling, planning, and adaptive management, BC's forests can hopefully be a part of a climate change solution.