Changes

==Projected==

==Projected==

*Increase in frequency and intensity of extreme precipitation events between now and 2100 <ref>Larson, L, Nicholas Rajkovich, and Clair Leighton. 2011. “Green Building and Climate Resilience: Understanding Impacts and Preparing for Changing Conditions.” University of Michigan, 260. </ref>

*Increase in frequency and intensity of extreme precipitation events between now and 2100 <ref>Larson, L, Nicholas Rajkovich, and Clair Leighton. 2011. “Green Building and Climate Resilience: Understanding Impacts and Preparing for Changing Conditions.” University of Michigan, 260. </ref>

* “The analysis indicates that there is likely to be an obvious warming trend with time over the entire province. The increase in average temperature is likely to be varying within:

*“The analysis indicates that there is likely to be an obvious warming trend with time over the entire province. The increase in average temperature is likely to be varying within:

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*2.6 - 2.7 °C in the 2030s,  

*2.6 - 2.7 °C in the 2030s,  

*3.2 - 17.5 % in the 2080s.}}  

*3.2 - 17.5 % in the 2080s.}}  

Furthermore, projections of rainfall intensity–duration–frequency (IDF) curves are developed to help understand the effects of global warming on extreme precipitation events. The results suggest that there is likely to be an overall increase in the intensity of rainfall storms. Finally, a data portal named Ontario Climate Change Data Portal (CCDP) is developed to ensure decision-makers and impact researchers have easy and intuitive access to the refined regional climate change scenarios.” <ref>Wang, Xiuquan, Guohe Huang, Jinliang Liu, Zhong Li, and Shan Zhao. 2015. “Ensemble Projections of Regional Climatic Changes over Ontario, Canada.” Journal of Climate 28 (18):7327–46. https://doi.org/10.1175/JCLI-D-15-0185.1.</ref>

Furthermore, projections of rainfall intensity–duration–frequency (IDF) curves are developed to help understand the effects of global warming on extreme precipitation events. The results suggest that there is likely to be an overall increase in the intensity of rainfall storms. Finally, a data portal named Ontario Climate Change Data Portal (CCDP) is developed to ensure decision-makers and impact researchers have easy and intuitive access to the refined regional climate change scenarios.” <ref>Wang, Xiuquan, Guohe Huang, Jinliang Liu, Zhong Li, and Shan Zhao. 2015. “Ensemble Projections of Regional Climatic Changes over Ontario, Canada.” Journal of Climate 28 (18):7327–46. https://doi.org/10.1175/JCLI-D-15-0185.1.</ref>

* “Some researchers, however, have demonstrated that the volume (Kuchenbecker et al. 2010, in Germany; cited in Bendel et al. 2013), frequency (Bendel et al. 2013, in Germany; Fortier and Mailhot 2014, May and October in Canada) or mean annual duration (Fortier and Mailhot 2014,in Canada) of CSOs should increase in the future climate. Logically, these increases will cause water quality to deteriorate in urban rivers – impacts that could be more severe as a result of increased water temperature.”  St-Hilaire et al 2016

*“Some researchers, however, have demonstrated that the volume (Kuchenbecker et al. 2010, in Germany; cited in Bendel et al. 2013), frequency (Bendel et al. 2013, in Germany; Fortier and Mailhot 2014, May and October in Canada) or mean annual duration (Fortier and Mailhot 2014,in Canada) of CSOs should increase in the future climate. Logically, these increases will cause water quality to deteriorate in urban rivers – impacts that could be more severe as a result of increased water temperature.”<ref>St-Hilaire, André, Sophie Duchesne, and Alain N Rousseau. 2016. “Floods and Water Quality in Canada: A Review of the Interactions with Urbanization, Agriculture and Forestry.” Canadian Water Resources Journal / Revue Canadienne Des Ressources Hydriques 41 (1–2). Taylor & Francis:273–87. https://doi.org/10.1080/07011784.2015.1010181.</ref>

** For York Region: “

===York Region===

*Of all temperature variables, the minima are anticipated to increase the most significantly by the 2050s in all seasons and on an annual basis (i.e. minimum temperature, average minimum temperatures)

*Of all temperature variables, the minima are anticipated to increase the most significantly by the 2050s in all seasons and on an annual basis (i.e. minimum temperature, average minimum temperatures)

*Precipitation is expected to increase annually and over most months; however, may in fact remain relatively consistent or decrease compared with the current climate for the summer season

*Precipitation is expected to increase annually and over most months; however, may in fact remain relatively consistent or decrease compared with the current climate for the summer season

*Extreme precipitation events are likely to increase in magnitude and in frequency, particularly in the summer time when convective activity is highest in and surrounding York Region. The future trend of extreme precipitation intensity; however, is unclear. It is recommended that a conservative approach should be taken in planning and adapting for extreme precipitation events.

*Extreme precipitation events are likely to increase in magnitude and in frequency, particularly in the summer time when convective activity is highest in and surrounding York Region. The future trend of extreme precipitation intensity; however, is unclear. It is recommended that a conservative approach should be taken in planning and adapting for extreme precipitation events.

*The growing season in York Region is expected to lengthen by over 30 days by the 2050s. With this, the start date will shift earlier and the end date will shift later in the year. It is less certain, but more likely than not, that drier conditions will be present throughout the growing season in the 2050s as a result of no significant increase in precipitation over summer months and significant increases in temperatures.”<ref>OCC, GLISA, Clean Air Partnership. 2016. “Historical and Future Climate Trends in York Region.”</ref>

*The growing season in York Region is expected to lengthen by over 30 days by the 2050s. With this, the start date will shift earlier and the end date will shift later in the year. It is less certain, but more likely than not, that drier conditions will be present throughout the growing season in the 2050s as a result of no significant increase in precipitation over summer months and significant increases in temperatures.”<ref>OCC, GLISA, Clean Air Partnership. 2016. “Historical and Future Climate Trends in York Region.”</ref>

* “If [winter] precipitation falls as rain instead of snow, which may actually occur more frequently in temper- ate regions with climate change, phosphorus concentrations in winter have the potential to be equivalent to those observed in other seasons due to the ubiquitous impacts of runoff events.”  Long et al 2014, a study done in Hamilton, ON

* “If [winter] precipitation falls as rain instead of snow, which may actually occur more frequently in temperate regions with climate change, phosphorus concentrations in winter have the potential to be equivalent to those observed in other seasons due to the ubiquitous impacts of runoff events.” “Another potential impact of climate change on summer nutrient conditions that has been discussed in the literature is an increase of summer soluble reactive phosphorus (SRP) concentrations in creeks during low flow conditions due to temperature-dependent release from riverine sediments.”<Ref>Long, Daniel L., and Randel L. Dymond. 2014. “Thermal Pollution Mitigation in Cold Water Stream Watersheds Using Bioretention.” Journal of the American Water Resources Association 50 (4):977–87. https://doi.org/10.1111/jawr.12152.</ref>

* “Another potential impact of climate change on summer nutrient conditions that has been discussed in the literature is an increase of summer soluble reactive phosphorus (SRP) concentrations in creeks during low flow conditions due to temperature-dependent release from riverine sediments.”  Long et al 2014

* “Dominguez et al. (2012) found increases in the intensity of 20- and 50-year return period winter precipitation events over the western United States, while over Canada, Mailhot et al. (2012) showed that the intensity of annual maxima precipitation would increase, with the largest increases for Ontario, the Prairies and Southern Quebec.”<ref>Guinard, Karine, Alain Mailhot, and Daniel Caya. 2015. “Projected Changes in Characteristics of Precipitation Spatial Structures over North America.” International Journal of Climatology 35 (4):596–612. https://doi.org/10.1002/joc.4006.</ref>

* “Dominguez et al. (2012) found increases in the intensity of 20- and 50-year return period winter precip- itation events over the western United States, while over Canada, Mailhot et al. (2012) showed that the intensity of annual maxima precipitation would increase, with the largest increases for Ontario, the Prairies and Southern Quebec.”  from Guinard et al 2015

* “The hydrological response to climate change was investigated through stormwater runoff volume and peak flow, while the water quality responses were investigated through the event mean value (EMV) of five parameters: turbidity, conductivity, water temperature, dissolved oxygen (DO) and pH. First flush (FF) effects were also noted. Under future climate scenarios, the EMVs of turbidity increased in all storms except for three events of short duration. The EMVs of conductivity were found to decline in small and frequent storms (return period <5 years); but conductivity EMVs were observed to increase in intensive events (return period ½5 years). In general, an increasing EMV was observed for water temperature, whereas a decreasing trend was found for DO EMV. No clear trend was found in the EMV of pH. In addition, projected future climate scenarios do not produce a stronger FF effect on dissolved solids and suspended solids compared to that produced by the current climate scenario.”<ref>He, Jianxun, Caterina Valeo, Angus Chu, and Norman F. Neumann. 2011. “Stormwater Quantity and Quality Response to Climate Change Using Artificial Neural Networks.” Hydrological Processes 25 (8):1298–1312. https://doi.org/10.1002/hyp.7904.</ref>

* “The hydrological response to climate change was investigated through stormwater runoff volume and peak flow, while the water quality responses were investigated through the event mean value (EMV) of five parameters: turbidity, conductivity, water temperature, dissolved oxygen (DO) and pH. First flush (FF) effects were also noted. Under future climate scenarios, the EMVs of turbidity increased in all storms except for three events of short duration. The EMVs of conductivity were found to decline in small and frequent storms (return period <5 years); but conductivity EMVs were observed to increase in intensive events (return period ½5 years). In general, an increasing EMV was observed for water temperature, whereas a decreasing trend was found for DO EMV. No clear trend was found in the EMV of pH. In addition, projected future climate scenarios do not produce a stronger FF effect on dissolved solids and suspended solids compared to that produced by the current climate scenario.”  He et al 2011

* “The potential consequences of climate change for P cycling in streams include (i) increasing prevalence of droughts and extreme summer low flows causing a reduction in baseflow dilution capacity, increased P retention during summer as residence times increase and a greater frequency of anoxia (Caruso, 2002; Van Vliet and Zwolsman, 2008), (ii) changes in magnitude and frequency of extreme high flows and floods causing reduced river P retention capacity and net in-channel loss of P under eutrophic conditions, greater seasonal variability in runoff volumes, carbon and nutrient inputs from terrestrial sources (e.g. more winter runoff and less summer runoff), scouring of streams and more frequent flushing of storm sewer overflows (Newson and Lewin, 1991; Schindler, 1997; Biggs et al., 2000; Bouraoui et al., 2002; Wilby et al., 2006a), (iii) greater range and higher average air tempera- tures causing warming of water temperatures in shallow streams, increasing the time window of biological activity, higher rates of primary production, increased soil wetting/ drying cycles, greater rates of OM mineralization and greater dissolved organic carbon (DOC) concentrations reaching the stream with impacts on microbial populations and metabolic rates (Wilby et al., 2006b; Durance and Ormerod, 2007; Harrison et al., 2008).”  Withers and Jarvie 2008 – study on phosphorus in rivers, this quote shows how climate change would also negatively impact the phosphorus cycle

* “The potential consequences of climate change for P cycling in streams include (i) increasing prevalence of droughts and extreme summer low flows causing a reduction in baseflow dilution capacity, increased P retention during summer as residence times increase and a greater frequency of anoxia (Caruso, 2002; Van Vliet and Zwolsman, 2008), (ii) changes in magnitude and frequency of extreme high flows and floods causing reduced river P retention capacity and net in-channel loss of P under eutrophic conditions, greater seasonal variability in runoff volumes, carbon and nutrient inputs from terrestrial sources (e.g. more winter runoff and less summer runoff), scouring of streams and more frequent flushing of storm sewer overflows (Newson and Lewin, 1991; Schindler, 1997; Biggs et al., 2000; Bouraoui et al., 2002; Wilby et al., 2006a), (iii) greater range and higher average air tempera- tures causing warming of water temperatures in shallow streams, increasing the time window of biological activity, higher rates of primary production, increased soil wetting/ drying cycles, greater rates of OM mineralization and greater dissolved organic carbon (DOC) concentrations reaching the stream with impacts on microbial populations and metabolic rates (Wilby et al., 2006b; Durance and Ormerod, 2007; Harrison et al., 2008).”  Withers and Jarvie 2008 – study on phosphorus in rivers, this quote shows how climate change would also negatively impact the phosphorus cycle

* Climate change can substantially increase future urban runoff volume and peak flow rate (Zahmatkesh et al 2016).

* Climate change can substantially increase future urban runoff volume and peak flow rate (Zahmatkesh et al 2016).