Climate change futures: health, ecological and economic dimensions

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While the role of allergen exposure alone in causing allergic diseases is unknown, allergens from pollen grains and fungal spores are unequivocally associated with exacerbation of existing disease. Changes in atmospheric chemistry and climate that tend to increase the presence of pollen and fungi in the air therefore contribute to a heightened risk of allergic symptoms and asthma. THE ROLE OF CLIMATE POLLEN Several studies have explored the potential impacts of CO 2 and global warming on plants. In general, increasing CO 2 and temperatures stimulate plants to increase photosynthesis, biomass, water-use efficiency and reproductive effort (Bazzaz 1990; LaDeau and Clark 2001). These are considered positive responses for agriculture, but for allergic individuals, they could mean increased exposure to pollen allergens. Figure 2.13 Pollen Grains Electron microscope image of ragweed pollen grains. Image: Johns Hopkins University Second, recent studies have shown increased plant reproductive effort and pollen production under conditions of elevated CO 2 . For example, loblolly pines respond to experimentally elevated CO 2 (200 ppm above ambient levels) by tripling their production of seeds and cones (LaDeau and Clark 2001). Long-term records at pollen monitoring stations in Europe show increasing annual pollen totals for several types of trees including hazel, birch and grasses (Spieksma et al. 1995; Frei 1998). For ragweed (Ambrosia artemisiifolia), a weed of open disturbed ground that produces potent pollen allergens, controlled-environment experiments show that plants grown at two times ambient CO 2 have greater biomass, and produce 40% to 61% more pollen than do controls (Ziska and Caulfield 2000; Wayne et al. 2002) (see figure 2.13). This finding was corroborated in field experiments using a natural urban-rural CO 2 gradient (Ziska et al. 2003). Figure 2.14 Ragweed Pollen Production Under Elevated CO 2 Percent increase above controls ragweed growth 70 60 50 40 30 20 10 0 350 ppm CO 2 700 ppm CO Carbon dioxide concentration Height Seed mass Pollen Biomass 2 49 | INFECTIOUS AND RESPIRATORY DISEASES Beyond these broad changes, climate warming has resulted in specific phenological changes in plants. First, the timing of spring budding has advanced in recent decades (Fitter and Fitter 2002; van Vliet et al. 2003). Hence the allergenic pollen season for many spring flowering plants also begins earlier (Jäger et al. 1996; Frei 1998; van Vliet et al. 2002). The rate of these advances is 0.84–0.9 days/year (Frenguelli et al. 2002; Clot 2003). While this is generally considered to be solely the effect of temperature, some studies suggest that CO 2 can independently affect the timing of phenological events as well (Murray and Ceulemans 1998). Plants grown at high CO 2 levels grow moderately more (9%) but produce significantly more (61%) pollen than those grown at lower levels. Source: Wayne et al. 2002 Increased temperature and CO 2 can also have interactive effects on pollen production due to longer growing seasons. In experiments simulating early spring, ragweed plants grew larger, had more flowers and produced more pollen than did plants started later. Those started later with high CO 2 produced 55% more pollen than did those grown at ambient CO 2 (Rogers et al. in review). CASE STUDIES
Figure 2.15 Ragweed MOLDS Long-term field experiments show that elevated CO 2 stimulates some symbiotic fungi (in mycorrhizal associations with tree roots) to grow faster and produce more spores (Klironomos et al. 1997; Treseder et al. 2003; Wolf et al. 2003). While further study is needed to examine this effect for a wide range of fungi and their complex associations in the ecosystem (Klironomos 2005), it is likely that higher CO 2 will enhance fungal growth directly created by CO 2 , and indirectly as fungi respond to the presence of increased plant biomass. Figure 2.17 Household Mold 50 | INFECTIOUS AND RESPIRATORY DISEASES CASE STUDIES Image: Dan Tenaglia/Missouriplants.com There are many ways climate change will alter the timing, production and distribution of airborne pollen allergens. For example, climate variability may alter the frequency of masting (periodic bursts of simultaneous reproduction of trees), which results in huge fluxes of airborne pollen from year to year. In addition, shifts in the distributions of species due to shifts in temperature regimes are also likely, as some species will be able to take advantage of new conditions while others will not (Ziska 2003). In some instances new habitats will be created for weeds after drought and fire. Lastly, although increased spring rainfall in some years and in some regions could decrease overall airborne concentrations (through washout) even if more pollen is produced, most changes in environmental factors act to increase the availability of pollen allergens. Figure 2.16 Soil Fungi Many soil fungi are arbuscular mycorrhizal fungi, living symbiotically with trees supplying nutrients and recycling decayed matter. Mushrooms are their flowering bodies. Image: Sara Wright/USDA Agricultural Research Service Household mold often follows flooding. Image: Chris Rogers HEALTH AND ECOLOGICAL IMPACTS Air quality directly affects the presence of asthma symptoms. A complex, serious condition characterized by shortness of breath, wheezing, airway obstruction, and inflammation of the lung passages, asthma commonly begins in childhood and requires frequent doctor visits, medications, emergency visits or hospitalizations. For developing nations and for those in poor communities, the health impacts of asthma can be significant. As developing countries incorporate modern technologies to cope with climate change (for example, air conditioning) on a wider scale, the resulting mold problems associated with poor building construction and maintenance will also increase without an influx of financial and technical resources.
Page 1 and 2: Climate Change Futures Health, Ecol
Page 3 and 4: Published by: The Center for Health
Page 5 and 6: PREAMBLE Hurricane Katrina 4 | PREA
Page 7 and 8: 6 | EXECUTIVE SUMMARY With this in
Page 9 and 10: 8 | EXECUTIVE SUMMARY Other non-lin
Page 11 and 12: THE CASE STUDIES IN BRIEF Floods in
Page 13 and 14: 12 | EXECUTIVE SUMMARY THE CCF PROJ
Page 16 and 17: PART I: The Climate Context Today
Page 18 and 19: (see McCarthy et al. 2001). As glac
Page 20 and 21: Table 1.1 Extreme Weather Events an
Page 22 and 23: DISCONTINUITIES CLIVAR, Climate Var
Page 24 and 25: Figure 1.6 The Frequency of Weather
Page 26 and 27: Figure 1.7 Trends in Events, Losses
Page 28 and 29: • Thawing of permafrost (permanen
Page 30 and 31: CCF-II: GRADUAL WARMING WITH INCREA
Page 32 and 33: PART II: Case Studies
Page 34 and 35: CLIMATE CHANGE AND EMERGING INFECTI
Page 36 and 37: HEALTH IMPACTS Malaria is character
Page 38 and 39: Figure 2.5 Brazil N Brazil COLOMBIA
Page 40 and 41: estimates (over and above current a
Page 42 and 43: SPECIFIC RECOMMENDATIONS Preventing
Page 44 and 45: 262 deaths in 2003; 7,470 cases and
Page 46 and 47: 98% of the two-year life cycle take
Page 48 and 49: The rise in minimum temperature res
Page 52 and 53: AIR QUALITY AND CLIMATE CHANGE ISSU
Page 54 and 55: EXTREME WEATHER EVENTS 1984 and 199
Page 56 and 57: HEALTH AND ECOLOGICAL IMPACTS Heat
Page 58 and 59: Figure 2.20 Projected Excess Deaths
Page 60 and 61: THE ROLE OF CLIMATE Australia exper
Page 62 and 63: Service). Since 2002, severe floods
Page 64 and 65: Table 2.1 Economic Losses in Europe
Page 66 and 67: NATURAL AND MANAGED SYSTEMS adelgid
Page 68 and 69: created unstable conditions conduci
Page 70 and 71: Climate research has already identi
Page 72 and 73: LOSSES ASSOCIATED WITH 1993 HEAVY P
Page 74 and 75: Figure 2.28 Soybean Rust Introducti
Page 76 and 77: Table 2.3 Extreme Weather Events Ca
Page 78 and 79: General measures to reduce the impa
Page 80 and 81: Physiological stresses on reef orga
Page 82 and 83: There are many questions concerning
Page 84 and 85: • Terminating practices that dest
Page 86 and 87: ecome contaminated with viruses and
Page 88 and 89: In 2001 the IPCC fully recognized t
Page 90 and 91: While seawater desalinization is cu
Page 92 and 93: PART III: Financial Implications, S
Page 94 and 95: Figure 3.1 Reinsurance Prices Are H
Page 96 and 97: RISK SPREADING IN DEVELOPED AND DEV
Page 98 and 99: THE LIMITS OF INSURABILITY Not all
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(also known as “cash-flow underwr
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from areas plagued by persistent dr
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Engagement of the insurance industr
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Industry observers point out that p
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CONCLUSIONS AND RECOMMENDATIONS Jus
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FINANCIAL INSTRUMENTS Regulators an
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of carbon-risk hedging products, su
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Summary Table of Extreme Weather Ev
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Table B.1 Summer Percentage Frequen
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Climate sensitivity for small-scale
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diffuse and do not manifest in sing
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APPENDIX D. LIST OF PARTICIPANTS AT
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Carmenza Robledo Gruppe Oekologie E
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126 | BIBLIOGRAPHY Bibliography AAA
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128 | BIBLIOGRAPHY Chordas, L. Epid
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Ford, S.E. & Tripp, M.R. Diseases a
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132 | BIBLIOGRAPHY Kalkstein, L. S.
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134 | BIBLIOGRAPHY Mills, E. The in
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136 | BIBLIOGRAPHY Rose, J. B., Eps
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138 | BIBLIOGRAPHY Vandyk, J. K., B
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Infectious and Respiratory Diseases
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Climate change futures: health, ecological and economic dimensions

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