Changes

==Observed to date==

==Observed to date==

* IDF: Changing rainfall intensities affect stormwater runoff timing, peak rates and volumes; Methods have been relying on static IDF curves. Increased frequency of 12% and increase intensity of 16% of extreme precipitation events for 1958 - 2007 for the US Northeastern region <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. http://scholar.google.com/scholar?hl=en&btnG=Search&q=intitle:GREEN+BUILDING+AND+CLIMATE+RESILIENCE+Understanding+impacts+and+preparing+for+changing+conditions#0.</ref>

*IDF: Changing rainfall intensities affect stormwater runoff timing, peak rates and volumes; Methods have been relying on static IDF curves. Increased frequency of 12% and increase intensity of 16% of extreme precipitation events for 1958 - 2007 for the US Northeastern region <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. http://scholar.google.com/scholar?hl=en&btnG=Search&q=intitle:GREEN+BUILDING+AND+CLIMATE+RESILIENCE+Understanding+impacts+and+preparing+for+changing+conditions#0.</ref>

* “Percent changes in the amount of precipitation falling in very heavy events (the heaviest 1 %) from 1958 to 2012 for each region. There is a clear national trend toward a greater amount of precipitation being concentrated in very heavy events, particularly in the Northeast US (71 %) and Midwest US (37 %).” <ref>Melillo, Jerry M, T C Richmond, Gary W Yohe, and US National Climate Assessment. 2014. Climate Change Impacts in the United States: The Third National Climate Assessment. US Global Change Research Program. Vol. 841. https://doi.org/10.7930/j0z31WJ2.</ref>

*“Percent changes in the amount of precipitation falling in very heavy events (the heaviest 1 %) from 1958 to 2012 for each region. There is a clear national trend toward a greater amount of precipitation being concentrated in very heavy events, particularly in the Northeast US (71 %) and Midwest US (37 %).” <ref>Melillo, Jerry M, T C Richmond, Gary W Yohe, and US National Climate Assessment. 2014. Climate Change Impacts in the United States: The Third National Climate Assessment. US Global Change Research Program. Vol. 841. https://doi.org/10.7930/j0z31WJ2.</ref>

* “As for the temporal trends, significant warming trends are detected throughout the province of Ontario and the overall trend in annual mean temperature varies largely between 0.01 and 0.02 °C year^–1. Increasing trends in annual rainfall (by 1 – 3 mm/year) and total precipitation (by 1 – 4 mm/year) are detected at the vast majority of gauged stations, but no significant trends in annual snowfall are identified at most of the stations.”<ref>Wang, Xiuquan, Guohe Huang, and Jinliang Liu. 2016. “Observed Regional Climatic Changes over Ontario, Canada, in Response to Global Warming.” Meteorological Applications 23 (1):140–49. https://doi.org/10.1002/met.1541.</ref>

*“As for the temporal trends, significant warming trends are detected throughout the province of Ontario and the overall trend in annual mean temperature varies largely between 0.01 and 0.02 °C year^–1. Increasing trends in annual rainfall (by 1 – 3 mm/year) and total precipitation (by 1 – 4 mm/year) are detected at the vast majority of gauged stations, but no significant trends in annual snowfall are identified at most of the stations.”<ref>Wang, Xiuquan, Guohe Huang, and Jinliang Liu. 2016. “Observed Regional Climatic Changes over Ontario, Canada, in Response to Global Warming.” Meteorological Applications 23 (1):140–49. https://doi.org/10.1002/met.1541.</ref>

* “Extreme downpours are now happening 30 % more often nationwide than in 1948. In other words, large rain or snowstorms that happened once every 12 months, on average, in the middle of the 20th century now happen every nine months. Moreover, the largest annual storms now produce 10 percent more precipitation, on average.” <ref>Madsen, Travis, and Nathan Willcox. 2012. “When It Rains, It Pours Global Warming and the Increase in Extreme When It Rains, It Pours Global Warming and the Increase in Extreme Precipitation from 1948 to 2011.” www.environmentamericacenter.org.</ref>

*“Extreme downpours are now happening 30 % more often nationwide than in 1948. In other words, large rain or snowstorms that happened once every 12 months, on average, in the middle of the 20th century now happen every nine months. Moreover, the largest annual storms now produce 10 percent more precipitation, on average.” <ref>Madsen, Travis, and Nathan Willcox. 2012. “When It Rains, It Pours Global Warming and the Increase in Extreme When It Rains, It Pours Global Warming and the Increase in Extreme Precipitation from 1948 to 2011.” www.environmentamericacenter.org.</ref>

* “Extreme weather events including prolonged heat waves, torrential rainstorms, windstorms, and drought have increased throughout Ontario in recent years (Ontario, 2011). The frequency of very hot days (above 32°C) is expected to increase by 2.4-fold in Ontario by the late 21st century <ref>Thunder Bay. 2015. “Climate-Ready City: City of Thunder Bay Climate Adaptation Strategy,” no. December:116.</ref>

*“Extreme weather events including prolonged heat waves, torrential rainstorms, windstorms, and drought have increased throughout Ontario in recent years (Ontario, 2011). The frequency of very hot days (above 32°C) is expected to increase by 2.4-fold in Ontario by the late 21st century <ref>Thunder Bay. 2015. “Climate-Ready City: City of Thunder Bay Climate Adaptation Strategy,” no. December:116.</ref>

* “Increases in the frequency and magnitude of extreme rainfall events have been documented in New York State. These changes are among the largest seen within the United States (DeGaetano 2009). Climate change projections suggest that these increases will continue <ref>Tryhorn, Lee. 2010. “Improving Policy for Stormwater Management: Implications for Climate Change Adaptation.” Weather, Climate, and Society 2 (2):113–26. https://doi.org/10.1175/2009WCAS1015.1.</ref>

*“Increases in the frequency and magnitude of extreme rainfall events have been documented in New York State. These changes are among the largest seen within the United States (DeGaetano 2009). Climate change projections suggest that these increases will continue <ref>Tryhorn, Lee. 2010. “Improving Policy for Stormwater Management: Implications for Climate Change Adaptation.” Weather, Climate, and Society 2 (2):113–26. https://doi.org/10.1175/2009WCAS1015.1.</ref>

==Projected==

==Projected==