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Canadian climate service providers offer projections from the Coupled Model Intercomparison Project (CMIP6) to help inform climate change mitigation and adaptation decisions. CMIP6 includes several "hot" climate models whose sensitivity to greenhouse gas forcings exceeds the likely range inferred from multiple lines of evidence. Global warming estimates assessed in the Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC) were reduced by applying observational constraints on the historical rate of warming to the CMIP6 ensemble. This study assesses whether globally constrained CMIP6 projections for Canada are appreciably different from unconstrained projections. Two constraints are considered: one that removes models whose transient climate response lies outside the AR6 assessed range (TCRlikely), and the other that weights models to match the assessed distribution of equilibrium climate sensitivity (ECSall). Both constraints lead to appreciably cooler and drier projections than the unconstrained ensemble, with the strongest reductions seen in the upper end of the ensemble range, high-emissions scenario, end-of-century time period, and northern regions of Canada. In this case, constrained projections of annual mean temperature are 2°–3°C cooler than the unconstrained projections, whereas projections of annual total precipitation are typically 20%–40% drier. Appreciable differences are also detected in the ensemble median of temperature extreme indices. Based on these results, it is recommended that a constrained ensemble be considered for regional projections to avoid the "hot model" problem. Alternatively, projections can be communicated conditional on a specified level of global warming, with global constraints then used to inform the timing of the warming level exceedance. [ABSTRACT FROM AUTHOR]

Canada is recognized as a global leader in sustainable forest management. Canadian forests and the forest sector remain vital pillars of the Canadian economy and home to many rural and remote communities. However, climate change is an existential threat to the sustainability of forests and forest-dependent communities. While both direct and indirect threats posed by climate change to Canada's forest sector are now well understood, our understanding of specific forest practices that have emerged from the body of science to mitigate and adapt to climate change impacts is not well documented. Through a review of the scientific and grey literature, this study expands our knowledge and operational gaps associated with implementing climate change adaptation and mitigation practices in Canadian forests. The study found a dearth of literature specifically dedicated to reporting on the type of forest practices currently in use across Canada to address mitigation and adaptation. Most reports or studies were published in 2019 or later, with federal and provincial governments being the dominant actors in reporting and monitoring, research, and funding. Across the 15 terrestrial ecozones in Canada, forest practices linked to climate change were reported in 12 ecozones, with most practices reported in the Montane Cordillera located in western Canada. Common forest practices reported include fuel management, assisted migration, enhanced silvicultural activities, and carbon offset projects. We conclude that climate change adaptation/mitigation practices in Canada are in their early stages of implementation. Many practices remain in experimental stages (e.g., genetic trials) or are implemented at a relatively small scale in Canada (e.g., climate-based seed transfer and carbon reserves). The literature suggests that the most mainstream practices associated with climate change mitigation in Canada include tree planting for carbon sequestration and the designation of protected areas to enhance ecosystem resilience. We conclude that despite increasing reports linking climate change benefits with reported forest practices, the reporting in the scientific literature is scarce, poorly reported, and often not grounded in credible evidence. [ABSTRACT FROM AUTHOR]

With its northern location, the exposure and vulnerability of Canada's forest ecosystems to climate change impacts are all too glaring. While there is now an extensive body of literature describing expected climate change impacts and potential responses, studies characterizing the implementation of adaptation and mitigation practices in forest management remain rare in the Canadian forest sector. Using a systematic literature review, we examined reports on forest management practices implemented in response to climate change, specifically focusing on governance and institutional arrangements that either support or limit climate change adaptation and mitigation responses. Our literature sample size of 24 documents suggests that the body of literature reporting on adaptation and mitigation practices in forest management is scarce. Governments remain the dominant actors providing funding and leading the implementation and reporting of climate change adaptation practices, primarily in response to national or international climate change commitments. Forest practices such as enhanced silviculture, assisted migration, and nature-based solutions were the most frequently reported. However, given the scarcity of literature, it is difficult to conclude the scope of climate change adaptation practice uptake in Canada. Barriers such as lack of information/data, inter-jurisdictional knowledge transfer, policy conflicts, forest tenure models, technical capacity gaps, and economic barriers to adaptation need to be overcome to strengthen climate change response in forest management. Better coordination of reporting at the provincial and national levels and improved information flows between private sector organizations and governments are needed. [ABSTRACT FROM AUTHOR]

Global commitments to protected area expansion should prioritize opportunities to protect climate refugia and ecosystems which store high levels of irrecoverable carbon, as key components of an effective response to biodiversity loss and climate change. The United States and Canada are responsible for one‐sixth of global greenhouse gas emissions but hold extensive natural ecosystems that store globally significant above‐ and below‐ground carbon. Canada has initiated a process of protected area network expansion in concert with efforts at reconciliation with Indigenous Peoples, and acknowledged nature‐based solutions as a key aspect of climate change mitigation. The US, although not a party to global biodiversity conventions, has recently committed to protecting 30% of its extent by 2030 and achieving the UNFCCC Paris Agreement's mitigation targets. The opportunities afforded by these dual biodiversity conservation and climate commitments require coordinated national and regional policies to ensure that new protected areas maximize biodiversity‐focused adaptation and nature‐based mitigation opportunities. We address how global commitments can best inform national policy initiatives which build on existing agency mandates for regional planning and species conservation. Previous analyses of global conservation priorities under climate change have been tenuously linked to policy contexts of individual nations and have lacked information on refugia due to limitations of globally available datasets. Comparison and synthesis of predictions from a range of recently developed refugia metrics allow such data to inform planning despite substantial uncertainty arising from contrasting model assumptions and inputs. A case study for endangered species planning for old‐forest‐associated species in the US Pacific Northwest demonstrates how regional planning can be nested hierarchically within national biodiversity‐focused adaptation and nature‐based mitigation strategies which integrate refugia, connectivity, and ecosystem carbon metrics to holistically evaluate the role of different land designations and where carbon mitigation and protection of biodiversity's resilience to climate change can be aligned. [ABSTRACT FROM AUTHOR]