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This text explores the effects of increasing carbon dioxide levels on temperature, seasonality, water resources, agriculture, and insect populations, highlighting the potential risks and challenges for various sectors. It also discusses the impacts on crop yields, livestock industries, and natural vegetation.
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Recent CO2 Changes IPCC Reports
Changes in Temperature 2 to 5° F by 2050
Changes in Seasonality Warmer winters earlier springs
Water Resources
Drought Increasing Dry Episodes Return of Mega-droughts
Snowpack Reduced levels at low elevations
Extra-local Influences
Agriculture in Southern California Each year, even with heat abatement efforts, extreme heat costs America’s livestock industries (dairy, beef, swine, and poultry) a collective 1.7 billion dollars. These losses come in the form of increased mortality, decreased appetite, decreased milk and egg production, and decreased reproductive fitness. Yields of cherries, berries, table grapes, wine grapes, walnuts, and freestone peaches are projected to decline by 2050, while almond yields slightly increase during this period. Increases in average May daily low temperatures help avocado production to some degree, once this value exceeds 53.6 degrees Fahrenheit, the yields go down at a rate of about ten tons per acre for every 1.8 degree Fahrenheit increase in daily low temperature.
Warmer winterlow temps In Citrus,lyears when the December temperature was 3.6 degrees Fahrenheit warmer than average produced crop yields that were five tons per acre larger than average.
Changes in Seasonality Warmer winters earlier springs
Warmer Temperatures (Pathogens and Disease) In General Fungi that infects crop plants grow best in moderate temperatures (earlier and longer warm periods) Wheat and Oats Host plants may become more susceptible to rust disease. Forage species become more resistant to fungi
Moisture Changes (Pathogens and Disease) • More frequent and extreme precipitation events could result in more and longer periods with favorable pathogen environments • Some pathogens will expand with increased moisture, whereas others will expand with reduced moisture. • Predicted higher atmospheric water vapor concentrations with increased temperature will favor pathogen and disease development.
Relative surface area of crops in California for 2006
Rising CO2 Concentrations (Pathogens and Disease) Impacts will be on both host and pathogens. CO2 fertilization will result in denser canopies, thus higher humidity favoring pathogens Lower plant decomposition from higher CO2 may provide cover for overwintering, thus earlier and faster disease cycles. Physiological changes to plant as well as pathogen
Allergies and Disease Increasing pollen numbers and allergy strength Spread of new diseases Mosquito-Borne Rodent-Borne Water-Borne
Warmer Temperatures (Insects) In General Increased temperature could increase pest populations Warmer temperatures can affect insect survival, development, geographic range, and population size Temperatures can affect insect development directly or indirectly
The Historic Record • Insect species diversity per area tends to decrease with higher latitude and altitude, meaning that rising temperatures could result in more insect species attacking more hosts in temperate climates • The diversity of insect species and the intensity of their feeding have increased historically with increasing temperatures. (Bale et al. 2002)
Insects Those that take several years per life-cycle • These insects will tend to moderate temperature variability over the course of their life history. Stop and go developers • Develop more rapidly during warm periods . • Increased temperatures will accelerate the development of these types of insects (more generations = more crop damage)
Insects • Migratory Insects • Areas where they overwinter may expand with warming temperatures. • Natural enemies and host insects may respond differently. Host insects may accelerate growth resulting in less parasitism. • Changes in temperatures • may shift gender ratios