LANDSCAPE AND CLIMATE CHANGE IN THE CENTRAL CANADIAN ROCKIES DURING THE 20TH CENTURY

This paper reviews selected evidence of environmental changes in the central Canadian Rockies during the 20th century. The instrumental climate record shows that mean annual temperatures have risen ca. 1.4°C over the last 100 years but seasonal patterns of change are complex. The greatest increases have been in winter temperatures (3.2°C / century). Precipitation data, though limited, show variable patterns of change on decadal scales with generally higher levels of precipitation in the mid-20th century. The longest streamflow record also shows considerable variability, with highest flows in the 1950s. A tree-ring-based temperature reconstruction indicates summer and spring temperatures in the last half of the 20th century are higher than any equivalent period over the last 900 years. Although no accurate regional estimates exist, glaciers have probably lost ca. 25% of their area in the last 100 years and may be smaller now than they have been at any time in the last 3000 years. These two lines of evidence suggest that the climate of the late 20th century is exceptional in the context of the last 1000 to 3000 years. Small but significant vegetation changes are taking place at the upper treeline ecotone in response to climate changes over the 20th century (e.g., seedling establishment). However, the most significant landscape change in the last 100 years is the transformation of the character of the montane forest due to a reduction in forest fire frequency, largely due to an active policy of fire suppression. Dans cet article, on révise certaines manifestations des changements environnementaux qui se sont produits dans les Rocheuses canadiennes au cours du 20^ème siècle. Ce registre instrumental climatologique indique que les moyennes annuelles de température ont augmenté d'environ 1,4°C en 100 ans, mais les modèles de changements saisonniers sont complexes. Les plus fortes augmentations ont été notées dans les températures hivernales (3,2°C/siècle). Les données concernant les précipitations - bien que limitées - indiquent des tendances variables de changement selon les décennies et en général des niveaux plus élevés de précipitation au milieu du 20^éme siècle. Le plus long enregistrement des débits d'un cours d'eau indique aussi d'importantes variations, les débits les plus forts se situant dans les années 1950. La reconstruction des relevés des températures faite à partir des cernes montre que les températures estivales et printanières de la deuxième moitié du 20^ème siècle sont plus élevées qu'elles ne l'étaient durant les périodes correspondantes des 900 dernières annés. Même s'il n'existe aucune donnée règionale exacte, les glaciers ont probablement perdu à peu près 25% de leur superficie au cours du dernier siècle et ils ont atteint leur plus petite taille des 3000 dernières années. Ces deux preuves suggèrent que le climat de la fin du 20^ème siècle est exceptionnel dans le contexte des 1000 à 3000 dernières années. Des changements mineurs mais significatifs s'effectuent actuellement dans l'écotone supérieur de la limite des arbres à cause des changements climatiques du 20^ème siècle (ex. l'implantation de nouvelles pousses). Pourtant, pendant le dernier siècle, la transformation la plus significative s'est effectuée dans les forêts de montagne. Grâce à une politique active de suppression des incendies de forêt, ceux-ci sont beaucoup moins fréquents.     

Climate change resilience in the Canadian Arctic: The need for collaboration in the face of a changing landscape

Human-induced changes to global climate have become increasingly difficult to ignore in recent years. As the frequency and severity of extreme weather events increases, the impacts on both natural and human systems are becoming difficult to manage with the current policies. In Canada, one of the most vulnerable regions to climate change is the Arctic, where temperatures are rising at a rate two to three times that of the global average. Warmer seasonal temperatures have led to melting permafrost and increased variability in sea ice conditions, which has contributed to a rise in coastal erosion. The ongoing resilience of Arctic communities will depend heavily on their ability to implement successful long-term adaptation policies. The development and implementation of any action on climate change adaptation should involve collaboration with local stakeholders in order to reflect the views and experience of those living in the Arctic.     

The changing biosphere: recent insights from paleoenvironmental science into drivers,mechanisms and impacts

Paleoenvironmental science has experienced a recent surge in interest and activity as concerns grow over global environmental change. Key research questions in the biotic realm of paleoenvironmental science focus on explaining climatic change at time scales of decades to centuries and understanding ecosystem responses to these changes. Biotic responses are increasingly being studied at smaller spatial scales to identify local factors that determine the sensitivity of a particular system to climatic change. These findings can then be applied to solving a variety of problems, such as setting conservation targets or testing mechanisms for observed climatic and biogeographic phenomena. Research approaches commonly used today include hypothesis testing, which has now become more sophisticated as paleoecologists and paleoclimatologists integrate with modellers. Other frameworks involve the quantitative integration of multiple proxy indicators and the use of extensive publicly available data networks to produce new datasets for paleoclimatic reconstructions and other applications.     

“Why would they care?”: Youth,resource extraction,and climate change in northern British Columbia,Canada

Discussion about local decision making tends to overlook rural and remote youth engagement. Resource extractive industries are, however, fixtures in many rural, remote, northern, and Indigenous communities in settler colonial British Columbia, Canada. These industries shape youths' perceived options for social and economic ventures when they are looking towards their futures. By engaging literature on climate change, settler colonialism, and critical Indigenous studies, and drawing on empirics from workshops conducted with youth from northern British Columbia, this paper explores how rural and remote northern and Indigenous youth engagement and perspectives can transform discussions on climate change and resource extraction. The paper documents how rural and northern youth have been engaged in environmental decision making, particularly in light of resource extraction. The paper also suggests that environmental decision making has at times been extractive itself. The paper concludes that when engaged meaningfully, youth desire to work collectively against social and environmental injustices.     

NDVI variation and its relation to climate in Canadian ecozones

Parks Canada began the Northern Satellite Monitoring Program in 1997, with the objective of tracking large‐scale vegetation variation in Canadian ecosystems and helping land managers to develop appropriate management practices in response to climate change. Under this program, a sequence of 10‐day composite Advanced Very High Resolution Radiometer (AVHRR)‐derived Normalized Difference Vegetation Index (NDVI) data from 1985 to 2007 was examined to study seasonal and inter‐annual relationships between vegetation and climate data over Canadian ecosystems using statistical and wavelet analysis. Statistical analysis showed that temperature was the principal driver for seasonal variability in greenness, explaining more than 70 percent of seasonal variation in vegetation for most Canadian ecozones. In comparison with temperature, the relationships between NDVI and precipitation were weaker but still significant. Maximum annual NDVI showed increasing trends in Canadian ecozones during the study period, although increasing rates were spatially heterogeneous. Wavelet analysis confirmed that inter‐annual variation in NDVI was different at two ecozones in Canada. NDVI variation in the Northern Arctic was significant at scales of 3–4 years from 1997 to 2001, which was associated with temperature and precipitation variation. Comparatively, NDVI variation in the Boreal Shield was significant at scales of 5–8 years from 1991 to 1999, but did not correspond with climate variation.     

Has it become warmer in Alberta? Mapping temperature changes for the period 1950–2010 across Alberta,Canada

When a Canada‐wide daily climate time series, covering the period 1950–2010, became available, an opportunity arose to analyze the time series for trends of a variety of temperature indices. The 6,833 climate grid cells covering Alberta, each with an area of 10 km by 10 km, allowed the detailed mapping of 30 temperature indices across the province. From each time series, an annual series was computed, which then enabled trend analyses using the non‐parametric Mann‐Kendall and Sen Slope tests. New maps could be created at an unprecedented spatial resolution, and an associated website was developed to access all trends and changes between 1950 and 2010 for all grid cells at albertaclimaterecords.com . The confidence levels of some temperature trends exceed 99%, while others are below 80%. In Alberta's south, annual average temperatures have increased by 1°C to 2°C since the 1950s, but in Alberta's north the increase is 2°C to 4°C. The growing season has lengthened by between one and five weeks since the 1950s, while the number of frost days has declined. The most significant trends observed were increases in mean annual and winter temperatures, and declines in the number of days below ?20°C and heating degree days.