PA Climate Futures Projections for the state constructed using averages of outputs from 14 GCMs Multi-model mean provides a credible simulation of PAs 20 th Century Climate, and is superior to any individual GCM Multi-model mean is slightly too cool and wet, and slightly muted in variability on sub-monthly time scales
Pa Very Likely to be warmer All GCM models project warming through 2100 for both emissions scenarios Warming for the next 20 years is independent of the emissions scenario Warming by the end of the century is substantially dependent on the emissions scenario A2 median projected warming about 4ºC B1 median projected warming about 2ºC
Greater Warming in Summer than Winter Means Emissions Scenario PeriodB2A1 2045-20652.0ºC2.5ºC 2080-20992.5ºC4.5ºC Emissions Scenario PeriodB2A1 2045-20651.5ºC2.0ºC 2080-20992.0ºC3.0ºC
PA Likely to Be Wetter Less model agreement on precipitation than warming But >3/4 project increased annual precipitation through the century for both emissions scenarios Like temperature, the change in precipitation does not vary with emissions scenario to mid-Century - but does beyond that A2 median projected increase in annual average precipitation about 10% by 2100
Precip Increases greater in Winter than Summer Average summer precipitation increase across all models is on the order of 0-5% during 2046-2065 and a little greater than that during 2080-2099. Average winter precipitation increases is ~5-10% during 2046-2065 and 10-15% during 2080-2099
Some other Climate Results Longer growing seasons, and fewer frost days, but also longer dry periods – soil moisture droughts a concern Greater intensity of precipitation Increased intensity but reduced frequency of tropical and extratropical systems
Water Resources Floods: Potential decrease in rain-on- snow events (good news), but more summer floods and higher flow variability. Stream temperature: Increase in stream temperature for most streams likely (e.g., bad for trout). Streams with high groundwater inflow less affected. Snow pack: Substantial decrease in snow cover extent and duration. Runoff: Overall increase, but mainly due to higher winter runoff. Decrease in summer runoff due to higher temperatures.
Water Resources Groundwater: Potential increase in recharge due to reduced frozen soil and higher winter precipitation. Soil moisture: Decrease in summer and fall soil moisture. Increased frequency of short and medium term soil moisture droughts. Water quality: Flashier runoff, urbanization and increasing water temperatures might negatively impact water quality.
Ecosystems Will Be Increasingly Stressed Wetlands and headwater streams in Pennsylvania are already compromised in their ability to provide ecosystem services Climate change will increase stresses on aquatic ecosystems Increased stream temperatures Increased flow variability Impacts will be difficult to detect because of the continuation of other stressors such as development and invasive species
Agriculture Moderate warming (1 to 3ºC) could…… Could increase yields of some major field crops (corn, hay, soybeans) Harm yields of cool-temperature adapted fruits and vegetables (potatoes, and apples) while benefiting those suited to warmer temperatures (sweet corn) Harm American grape varieties but create opportunities for European varieties Increase dairy production costs but increase the attractiveness of PA to southern hog and poultry producers
Agriculture More extreme warming poses greater problems Droughts, pests could be problematic Outcomes for PA farmers depend not only on climate change in PA, but what climate change does to agricultural markets and economies elsewhere World prices Shifts in location
Forests Species composition will shift as the climate becomes less suited to northern species and more suited to southern species NorthernSouthern American BeechLoblolly Black CherryShortleaf Pine Eastern HemlockCommon Persimmon Red and Sugar MapleRed Mulberry White PineOaks & Hickories
Forests Like agriculture Economic productivity could increase Benefits to the industry will depend on climate change impacts elsewhere Disease, invasive species, fire risks also increase
Temperature Related Mortality Mechanism of Impact Direction of ImpactLevel of Confidence in Direction of impact Higher summer temperatures cause an in increase in heat- related deaths High Higher winter temperatures cause a decrease in cold-related deaths High Net impact unknown Heat adaptations include air conditioning, warning systems; low income assistance needed
Respiratory Disease Mechanism of Impact Direction of ImpactLevel of Confidence in Direction of impact Higher summer temperatures cause in increased in ozone formation High Higher temperatures increase formation of airborne particulates Low Higher temperatures, higher CO2 levels and longer summer season increase prevalence of pollen and mold Low
Accidents Mechanism of Impact Direction of ImpactLevel of Confidence in Direction of impact Increases in flood and severe rainstorms Decreases in snow and ice storms Low
Infectious Diseases Vector Borne: Lyme, West Nile, St. Louis Encephalitis, Ehrilichiosis, Malaria Water Borne: Cryptosporidium, Giardia, Campylobacter, Salmonella Airborne: Influenza, Pneumococcus
Mechanism of Impact Direction of ImpactLevel of Confidence in Direction of impact Higher temperatures affect range and abundance of disease- carrying vectors Low Higher temperatures and runoff lead to increased concentration of water-borne pathogens in surface waters Medium Higher winter temperatures affect incidence of pneumonia and seasonal influenza Low Infections Diseases
Outdoor Recreation Increased winter temperatures will shorten the season and increase the costs of downhill ski facilities – the economic viability of the activity will be diminished Reduced snow cover will diminish opportunities for dispersed snow-based recreation (skiing, snow Increased stream temperatures will affect the viability of wild and to some degree stocked trout populations Increased temperatures will increase the number of fishing days Longer and warmer summers will increase the demand for water-based recreation
Ag cultivars and practices Forest management practices – cultivated forests with facilitated regeneration Institutions and policies for water management in an environment in which water is increasing scarce and variable Land use planning and building codes Restoration of aquatic ecosystems such as streams and wetlands wherever possible Expansion of public outdoor recreation facilities Proactive State and Local Adaptation Policy
Climate downscaling Reduce emission scenario uncertainty Detailed sectoral modeling studies Storm risk assessment Hydrologic conditions at a small watershed scale Ability of already impacted systems to accommodate climate change Health-climate-environment relationships New Research is Needed to Fully Understand Impacts
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