APPENDIX 6.5-B Knight Piésold Kitsault Mine Climate Change Assessment Letter KITSAULT MINE PROJECT ENVIRONMENTAL ASSESSMENT APPENDICES

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1 ENVIRONMENTAL ASSESSMENT APPENDICES APPENDIX 6.5-B Knight Piésold Kitsault Mine Climate Change Assessment Letter VE51988 Appendices

3 File No.:VA11-343/9-A.1 Cont. No.:VA Suite West Pender Street Vancouver, BC Canada V6C 2T8 Tel: Fax: July 13, 211 Mr. Craig Nelsen President & CEO Avanti Kitsault Mine Ltd Hornby Street Vancouver, BC V6C 3B6 Dear Craig, Re: Kitsault Mine Climate Change Assessment This letter presents an overview of historical regional climaticc and hydrologic trends for the Kitsaultt Mine Project, which were used to assess potential climate change patterns in the region. This assessment does not include any modelling of possible future climate change scenarios, the results of which are inherently uncertain and only applicable to much longer time scales than the next 15 to 2 year timeline of the project. Climate Change Analysis Overview There is a general consensus in the scientific community thatt the global atmosphere is warming and that worldwide climate patterns are correspondingly changing. The effects of these changes are having different impacts in different geographic regions. According to a 26 BC Government study on climate change, over the past half-century both minimum and maximum temperatures in the region near the Kitsault Mine have been warming, by approximately 1.2 C and 1. o C, respectively. Furthermore, for the period between 195 and 2, winter and summer precipitation also generally increased in the region, rising by between approximately 5% and 25%, respectivelyy (BC Gov, 26). Thesee changes, in turn, would have had an effect on hydrologic patterns. An increase in annual precipitation would logically be expected to increase runoff, but with coincident warmer temperatures, corresponding higher evaporation rates may have offset any potential increases. At the same time, however, the warmer temperatures would tend to raise the freezing levels and shorten the periods of snowfall, so that a greater proportion of the winter precipitation falling in a watershed would occur as rain, reducing the size of the snowpack and resulting in proportionally greater winter flows and lower freshet flows. Given these predicted changes, there is understandably some concern about whether or not historical flow and climate records, which were used to assess hydrometeorological conditions at the Kitsaultt Mine Project, reasonably represent conditions that might be expected over the next 15 to 2 years and beyond. In an effort to address this concern, admittedly at a veryy cursory level, historical trends of annual temperature, precipitation, and discharge weree examined in the general region of the Kitsault Mine Project. Climate Trends The Terrace A climate station (16813) has the longest andd most complete climate record in the region of the Kitsault Mine site, and therefore this dataset was selected to represent long-term climate conditions at the site. Plots of annual precipitation trends for this station are presented on Figure 1. Three of the six

4 trendlines presented are statistically significant at the 1% level: Annual Rainfall, Annual Snowfall, and Minimum Monthly Precipitation. This significance level means that one can be 9% confident that these trends are not due to random chance. The annual rainfall and snowfall trends indicate changes of +35 mm per decade and -2 cm per decade, respectively. These trends are strong indicators of warming winter temperatures, which are resulting in a greater proportion of winter precipitation falling as rain. The increase of 2.8 mm per decade in the minimum monthly precipitation, though statistically significant, suggests only a very minor decrease in precipitation variability. Interestingly, contrary to the BC Government findings for the region, the summer precipitation doesn t show any significant trend. Overall, it appears that precipitation patterns, other than the proportions falling as rain and snow, have not changed in any meaningful way, particularly if one considerss climate cycles, as is explained later in this discussion. Trend plots of annual temperaturee at Terrace A are presented on Figure 2. All trends except the maximumm temperaturee trend are significant at the 1% level. The trends suggest that the mean annual temperature in the region is increasing at a rate of approximately 1.6 ºC per century. In addition, the minimum mean monthly temperature and the minimum temperature exhibit statistically significant increasing trends of 5 o C per century and 6 o C per century, respectively. These trends are consistent with the decreasing snowfall and increasing rainfall trends discussed previously. Interestingly, maximum monthly temperatures appear to be decreasing, which suggests that there is a trend towards less variation in temperature extremes. Overall, it is believed that there has been a real trend of increasing temperatures in the project area over the past 5 years, and that temperature extremes appear to be moderating. However, as will be explained, this may be due to climate cycles rather than climate change, so it is not clear whether or not this trend will continue. Streamflow Trends Insights into possible long-term climate effects on streamflow in the Kitsault Mine Project Area are provided by examining the flow records for Hirsch Creek (8FF2) and the Zymoetz River (8EF5). These monitoring stations were selected for analysis because of their relatively long records (>4 yrs), the similarity of their annual hydrographs with that of Limee Creek (Figure 3), whichh is located at the Project site, and their trans-region representativeness, with Hirsch Creek situated to the west and therefore having a more coastal climate, and the Zymoetz River located to the east with a more interior climate. Ideally, WSC records on Lime Creek and Patsy Creek, both located within the Project area, would have been used to assess climate change impacts on hydrology; ; however, their relatively short records (< 15 years) do not allow for an assessment of long-term trends in the region. Neither regional hydrology record exhibits a positive or negative trend in mean annual runoff that is statistically significant at any reasonable level, as shown onn Figure 4. Similarly, trends of annual peak discharge are not statistically significant at any reasonable level (Figure 5). It is interesting to note that this lack of change in peak flow pattern is inconsistent with the general prediction of the Intergovernmental Panel on Climate Change (IPCC), which states that increased atmospheric energy is expected to result in increased snowmelt rates and increases in the amounts and frequency of extreme precipitation (IPCC-AR4, 27). Despite the lack of statistical significance in the annual streamflow trends, there is a very obvious shift in the annual flow patterns of the regional stations between the first half of their records ( ) and the second half ( ), as indicated on Figure 6. As expected, the proportion of runoff occurring during the winter months increased in the latter half of the regionall records, while the proportion that occurred during the high flow freshet and late summer periods decreased in both systems. The snowmelt freshet is also occurring earlier in the latter half of the records. These changes in the annual hydrograph shape 2 of 4 VA July 13, 211

5 can be primarily attributed to higher autumn and winterr temperatures that result in more winter precipitation falling as rain, a higher snowline, and a corresponding smaller snowpack. Warmer spring temperatures then melt this snowpack at an earlier date. It should be noted that both regional watersheds appear to have very small proportions of glaciated or permanent snowfield areas, and the ongoing reduction of these area is likely contributing to much of the change in late summer streamflow patterns in i these watersheds. However, despite the watersheds within the Project Area lacking this permanent snow or ice cover, it is still possible that late summer streamflow has, and will continue, to diminish as a result of an earlier onset of the freshet period. Climate Cycles It should be recognized that one of the primary factors inhibiting the detection of changing patterns in local climate and streamflow records is the influence of cyclical climate patterns. A number of normal cyclical climate patterns occur regularly in the Pacific-Northwest over both short-term and relatively long- term periods. A variety of different climate patterns have been identified in the literature, but the two most recognized phenomena are the Pacific Decadal Oscillation (PDO), whichh has both hot and cold phases that typically persist for 2 to 3 years, and the El Nino Southern Oscillation (ENSO), which operates on a much shorter time scale with phases typically lasting forr 6 to 18 months (Mantua, 21). Both phenomena are defined by changes of surface water temperatures in the Pacificc Ocean, and are associated with corresponding changes in climate. The PDO has the strongest signature, as ENSO influences on climate in a region are strongly dependent on the phase of the PDO (McCabe and Dettinger, 1999). The cold phase of the PDO is correlated with colder temperatures and above average winter precipitation, snowpack and annual runoff (Mantua, 21; Sellars et. al., 28), as well as an increased risk of winter and spring flooding (Mantua, 21) ). These conditions tend to be even more pronounced if the ENSO is in phase. There is some questionn as to what are the exact periods that define the most recent warm and cold phases of the PDO, but as indicated on Figure 7, the 1954 to 21 climate record for the Terrace A station essentially spans a cold phase followed by a warm phase. It is therefore not surprising that the historical data indicate a pattern of increasing temperatures. Whether this warming trend and its effect on hydrologic patterns will continue, or whether temperatures will start to trend downwards with the expected shift to cold phase in the PDO, is unclear. Summary To conclude, trends of increasing temperatures and corresponding changes to annual hydrograph patterns are evident in the regional climate and flow records. However, it is uncertain whether these trends will continue into the near future, given the inherent variability and cyclic nature of climate, although they are expected to persist to some degree over the long-term. Furthermore, given our current inability to accurately predict and model future climate patterns, the fact that the most relevant historical flow records indicate very little recent change in annual flow volumes or durations, and that the Kitsault Mine has a relatively short operating period (approximately 15 years), it is reasonable to conclude that current records should provide an appropriate basis for assessing mean hydrologic conditions in the project area during the life of the mine. References BC Government. 26. British Columbia Coast and Marine Environment Project _climate_change/technical_paper/climate_change.pdf 3 of 4 VA July 13, 211

7 M:\1\1\343\9\A\Data\Climate Change\Climate Change - MeteorologyTerrace Precipitation Trends Print 13/7/211 1:52 PM Annual Precipitation Maximum Monthly Precipitation Minimum Monthly Precipitation Annual Rainfall Annual Snowfall Summer Precipitation y = 1.74x Precipitation (mm) y = 3.53x y = -1.97x y = -.37x + 11 y =.39x - 69 y =.28x Year NOTES: 1. THE ANNUAL RAINFALL, ANNUAL SNOWFALL AND MAXIMUM MONTHLY PRECIPITATION TRENDS ARE ALL SIGNIFICANT AT THE.1 SIGNIFICANCE LEVEL. TERRACE A ANNUAL PRECIPITATION TRENDS 11JUL'11 ISSUED WITH LETTER KT ER JGC DATE DESCRIPTION PREP'D CHK'D APP'D VA11-343/9 FIGURE 1 REF. NO. VA11-175

8 M:\1\3\284\1\A\Data\WSC\[Climate Change - Meteorology.xls]Terrace Temperature Trends Print 12/7/211 1:42 PM Mean Annual Temperature Annual Maximum Mean Monthly Temperature Annual Extreme Maximum Temperature Annual Minimum Mean Monthly Temperature Annual Extreme Minimum Temperature 3. y =.1x Temperature ( o C) y = -.4x y =.2x y =.5x y =.6x Year NOTES: 1. ALL OF THE TERRACE A TEMPERATURE TRENDS PRESENTED ABOVE, EXCEPT THE ANNUAL EXTREME MAXIMUM TREND, ARE SIGNIFICANT AT THE.1 SIGNIFICANCE LEVEL. TERRACE A ANNUAL TEMPERATURE TRENDS 11JUL'11 ISSUED WITH LETTER KT ER JGC DATE DESCRIPTION PREP'D CHK'D APP'D VA11-343/9 FIGURE 2 REF. NO. VA11-175

9 M:\1\1\343\9\A\Data\Climate Change\[Climate Change - Hydrology.xls]Chart1 Print 12/7/211 1:44 PM Lime Creek Hirsch Creek Mean Monthly Unit Runoff (l/s/km 2 ) Zymoetz River 2 January February March April May June July August September October November December Month REGIONAL HYDROGRAPHS 11JUL'11 ISSUED WITH LETTER KT ER JGC DATE DESCRIPTION PREP'D CHK'D APP'D VA11-343/9 FIGURE 3 REF. NO. VA11-175

10 M:\1\1\343\9\A\Data\Climate Change\[Climate Change - Hydrology.xls]Chart2 Print 12/7/211 1:55 PM 9 8 Mean Annual Unit Runoff (l/s/km 2 ) y =.2x + 1 y =.2x Year NOTES: 1. NONE OF THE ABOVE TRENDS ARE STATISTICALLY SIGNIFICANT AT ANY REASONABLE LEVEL OF SIGNIFICANCE. Hirsch Creek REGIONAL MEAN ANNUAL DISCHARGE TRENDS 11JUL'11 ISSUED WITH LETTER KT ER JGC DATE DESCRIPTION PREP'D CHK'D APP'D Zymoetz River VA11-343/9 FIGURE 4 REF. NO. VA11-175

11 M:\1\1\343\9\A\Data\Climate Change\[Climate Change - Hydrology.xls]Chart4 Print 7/13/11 2:3 PM 25 2 Annual Peak Instantaneous Flow (l/s/km 2 ) 15 1 y = 1.45x y = 2.99x NOTES: 1. NONE OF THE ABOVE TRENDS ARE SIGNIFICANT AT ANY REASONABLE LEVEL OF SIGNIFICANCE. Year 11JUL'11 ISSUED WITH LETTER KT ER JGC DATE DESCRIPTION PREP'D CHK'D APP'D Hirsch Creek Zymoetz River REGIONAL PEAK ANNUAL DISCHARGE TRENDS VA11-343/9 FIGURE 5 REF. NO. VA11-175

12 M:\1\1\343\9\A\Data\Climate Change\[Climate Change - Hydrology.xls]Chart3 Print 12/7/211 1:47 PM 14 Hirsch Creek ( ) 12 Hirsch Creek ( ) Zymoetz River ( ) Mean Monthly Unit Runoff (l/s/km 2 ) Zymoetz River ( ) 2 January February March April May June July August September October November December Month CHANGE IN HYDROGRAPH SHAPE 11JUL'11 ISSUED WITH LETTER KT ER JGC DATE DESCRIPTION PREP'D CHK'D APP'D VA11-343/9 FIGURE 6 REF. NO. VA11-175

$M:\1\1\343\9\A\Data\Climate Change\Climate Change - Meteorology Print 13/7/211 1:49 PM COLD PHASE WARM PHASE NOTES: 1) SOURCE: JOINT INSTITUTE FOR THE STUDY OF THE ATMOSPHERE AND OCEAN$

13 M:\1\1\343\9\A\Data\Climate Change\Climate Change - Meteorology Print 13/7/211 1:49 PM COLD PHASE WARM PHASE NOTES: 1) SOURCE: JOINT INSTITUTE FOR THE STUDY OF THE ATMOSPHERE AND OCEAN THE PACIFIC DECADAL OSCILLATION INDEX FOR THE 2 TH CENTURY 13JUL'11 ISSUED WITH LETTER KT KT JGC DATE DESCRIPTION PREP'D CHK'D APP'D VA11-343/9 FIGURE 7 REF NO. VA11-175

2015: A YEAR IN REVIEW F.S. ANSLOW

2015: A YEAR IN REVIEW F.S. ANSLOW 1 INTRODUCTION Recently, three of the major centres for global climate monitoring determined with high confidence that 2015 was the warmest year on record, globally.