The Rate Debate Slowing
CO2 Agriculture Warming Bad - Empirics
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CO2 AgricultureWarming Bad - EmpiricsWarming kills argiculture – 4 reasons Hatfield 9/15/11 (Jeremy Hatfield, PHD, Laboratory Director and Supervisory Plant Physiologist @ Agricultural Research Service, http://www.ars.usda.gov/pandp/people/people.htm?personid=2378) Climate change over the next 30 to 50 years will place new stresses on agricultural production because of the increasing temperatures, increased variability in precipitation, enhanced potential for more extreme storms, and more differences within the growing season. There have been several assessments of the potential scenarios for climate change and Meehl et al. (2007) summarized that on a global basis “it is very likely that heat waves will be more intense, more frequent and longer lasting in a future warmer climate. Cold episodes are projected to decrease significantly in a future warmer climate. Almost everywhere, daily minimum temperatures are projected to increase faster than daily maximum temperatures, leading to a decrease in diurnal temperature range. Decreases in frost days are projected to occur almost everywhere in the middle and high latitudes, with a comparable increase in growing season length.” In terms of precipitation, they stated that “For a future warmer climate, the current generation of models indicates that precipitation generally increases in the areas of regional tropical precipitation maxima (such as the monsoon regimes) and over the tropical Pacific in particular, with general decreases in the subtropics, and increases at high latitudes as a consequence of a general intensification of the global hydrological cycle. Globally averaged mean water vapor, evaporation and precipitation are projected to increase” (Meehl et al., 2007). These summaries point out the expected global change in temperature and precipitation. Across North America there are expected changes in climate mirroring the worldwide changes. These have been summarized recently by Karl et al. (2009) where temperature and precipitation patterns across the United States for the next 50 years show a warming trend for most of the United States of 1.5 to 2.0°C and a slight increase in precipitation over most of the United States. Their projections of an increase in the number of days which the temperature will be higher than the climatic normals by 5°C (heat-waves) will impact agricultural systems. They also project an increase in warm nights, defined as occurring when the minimum temperature is above the 90th percentile of the climatological distribution for the day (Tebaldi et al., 2006; Karl et al., 2009). Coupled with these changes is the decrease in the number of frost days by 10% in the eastern half of the U.S. and an increase in the length of the growing season by over 10 days. Karl et al. (2009) showed that precipitation events would change in frequency and intensity with a projected increase in spring precipitation, particularly in the Northeast and Midwest of the United States, and a decline in the Southwestern U.S.. The increase in extreme temperature events, warm nights, and more variable precipitation will impact agriculture and agricultural production. A trend for warmer winters will affect perennial crops and weeds, and also expand the potential habitable range of some insect and disease pests. Although there is uncertainty about the absolute magnitude of the changes over the next 50 years, there is general agreement that CO2 levels will increase to near 450 μmol mol-1 (ppm), temperatures will increase by 0.8 to 1.0°C, and precipitation will become more variable as defined in the IPCC AR4 analysis (IPCC, 2007). Changes in temperature have caused longer growing seasons and directly impacted phenological phases (Schwartz et al., 2006; Wolfe et al., 2005, Xiao et al., 2008; Karl et al., 2009). There are changes occurring in climate and these will directly and indirectly affect plant growth and ultimately biofuel production. In this paper we summarize some of the potential scenarios in climate change and relate these to plant production in order to demonstrate the impact of climate change on biofuel production. Warming hurts plants – new long term study proves Science Daily 12 (4/9/12, “Climate Change Helps, Then Quickly Stunts Plant Growth, Decade-Long Study Shows” Science Daily, www.sciencedaily.com/releases/2012/04/120409103253.htm) Global warming may initially make the grass greener, but not for long, according to new research conducted at Northern Arizona University. The study, published this week in Nature Climate Change, shows that plants may thrive in the early stages of a warming environment but begin to deteriorate quickly. n"We were really surprised by the pattern, where the initial boost in growth just went away," said Zhuoting Wu, NAU doctoral graduate in biology. "As the ecosystems adjust, the responses changed." Researchers subjected four grassland ecosystems to simulated climate change during the decade-long study. Plants grew more the first year in the global warming treatment, but this effect progressively diminished over the next nine years, and finally disappeared. The research reports the long-term effects of global warming on plant growth, the plant species that make up the community, and the changes in how plants use or retain essential resources like nitrogen. The team transplanted four grassland ecosystems from higher to lower elevation to simulate a future warmer environment, and coupled the warming with the range of predicted changes in precipitation -- more, the same, or less. The grasslands studied were typical of those found in northern Arizona along elevation gradients from the San Francisco Peaks down to the great basin desert. The researchers found that long-term warming resulted in loss of native species and encroachment of species typical of warmer environments, pushing the plant community toward less productive species. The warmed grasslands also cycled nitrogen more rapidly, an effect that should make more nitrogen available to plants, helping them grow more. But instead much of the nitrogen was lost, converted to nitrogen gases lost to the atmosphere or leached out with rainfall washing through the soil. Bruce Hungate, senior author of the study and NAU Biological Sciences professor, said the research findings challenge the expectation that warming will increase nitrogen availability and cause a sustained increase in plant productivity. "Faster nitrogen turnover stimulated nitrogen losses, likely reducing the effect of warming on plant growth," Hungate said. "More generally, changes in species, changes in element cycles -- these really make a difference. It's classic systems ecology: the initial responses elicit knock-on effects which here came back to bite the plants. These ecosystem feedbacks are critical. You just can't figure this out with plants grown in a greenhouse. " The findings caution against extrapolating from short-term experiments, or experiments in a greenhouse, where experimenters cannot measure the feedbacks from changes in the plant community and from nutrient cycles. The research will continue at least five more years with current funding from the National Science Foundation and, Hungate said, hopefully for another five years after that. "The long-term perspective is key. We were surprised, and I'm guessing there are more surprises in store." Additional coauthors include George Koch, NAU professor of Biological Sciences, and Paul Dijkstra, assistant research professor of Biological Sciences. Directory: files files -> Answer True False 2 points Question 2 files -> Integer programming and game theory files -> 4 Integer Programming files -> Bpa vehicle Window Repair Scenario #1 task: Procure vehicle window relacement. 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