From Monsoons to Microbes Understanding the Ocean's Role in Human Health (1999) / Chapter Skim
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1 Climate and Weather, Coastal Hazards, and Public Health
1 Climate and Weather, Coastal Hazards, and Public Health
Pages 15-42
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From page 15... ...
Chapter 1: "Climate and Weather, Coastal Hazards, and Public Health," describes how public health is affected by marine processes such as ocean-dependent weather and climate effects, tropical storms, and estuarine and coastal circulation. Chapter 2: "Infectious Diseases," covers the various waterborne marine infectious diseases including bacterial, viral, and protozoa!
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From page 16... ...
This chapter will discuss why physical ocean properties have important implications for public health. Public Health Problems Caused by Tropical Storms and Other Marine Natural Disasters Natural disasters involving ocean processes include phenomena such as rain, tropical storms, tsunamis, storm surges, blooms of toxic algae, pathogen contamination of coastal waters, and recurring as well as long term climate variability.
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From page 17... ...
These events may either directly cause injury and death or indirectly cause the spread of various types of illness, including waterborne and vector-borne diseases, as well as illnesses associated with toxic algal blooms. The protection of public health requires a thorough understanding of the physical ocean environment for better forecasting and handling of marine disasters.
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. Without this "overturning" circulation, the surface waters would become depleted of nutrients and the deep waters would become depleted of oxygen, a stagnation observed seasonally in some freshwater lakes and in isolated marine basins and some estuaries.
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PUBLIC HEALTH PROBLEMS CAUSED BY TROPICAL STORMS AND OTHER MARINE NATURAL DISASTERS Natural disasters involving ocean processes include phenomena such as rain, tropical storms, tsunamis, storm surges, blooms of toxic algae, pathogen contamination of coastal waters, and recurring as well as long-term climate variability. The types of problems faced by the public health system are determined both by geography and the socioeconomic status of the affected country.
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From page 20... ...
The broad range in estimating mortality following the Bangladesh cyclone reflects the lack of reliable data on the consequences of natural disasters in most developing countries. Also, this dramatic loss of life illustrates the high-risk to the population in Bangladesh a combination of the frequent occurrence of cyclones and storm surges with an extremely vulnerable and unprepared population.
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The very fear of devastating outbreaks is an effective incentive to improve otherwise neglected basic sanitation and water control in many countries. Second, dilution of fecal contamination by tropical storm surges in overcrowded and heavily contaminated environments may reduce outbreaks.
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The delayed or indirect health impact of marine natural disasters is generally underestimated and under-reported. The long term cost to public health results from the interruption of health services, the permanent damage to infrastructure, the setback in development, and the loss of individual income.
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is higher now than in the past because of the growth and increased wealth of the coastal population; the population has been increasing at a rate of 4-5% per year (Sheets, 1990~. Millions of people live and vacation along the coastline and are exposed to the threat of tropical storm winds, rain, storm surge, and severe ~ Tropical storms is used as a general term to describe tropical storms and hurricanes, and cyclones.
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From page 24... ...
Unless the rate of forecast improvements can be accelerated, the downward trend of tropical storm casualties is not likely to continue, and the damage will continue to escalate. Track prediction is made more difficult by decadal climate variability, which leads to long-term variation in the frequency, intensity, origins, and paths of hurricanes.
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Ocean's Role in Modulating Intensity The ocean's influence on tropical storm pressure and wind variations is dependent on the transfer of heat from the surface waters to the atmosphere. The recent case of Hurricane Opal demonstrated that sudden unexpected intensifica 2 hPa = hectoPascals.
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From page 26... ...
Storm Surges Low atmospheric pressure causes sea level to increase underneath the storm. As the storm approaches landfall, cyclonically rotating surface winds on the right side of the eye push water onto the coast, whereas on the left side of the storm center water is driven away from the coastline.
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From page 27... ...
For example, seawalls are built to reduce damage from storm surges or to anticipate sea level rise, but they also decrease the number of functional wetlands and the potential for migration of wetlands in the event of sea level rise. There are fewer natural areas left to sustain the coastal ecosystem, increasing the vulnerability of remaining wetlands and estuaries to the destructive effects of storms.
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~ A, FRESH /7 WATER ~ FIGURE 1- lb Estuary circulation: if tidal currents are stronger, saltwater becomes mixed into the upper layer and gets transported seaward. Stratification weakens, but the twolayered flow regime remains: seaward at the surface and landward below, with net transport increased in both layers (Williams, 1962~.
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In fact, cysts of dinoflagellates (which can initiate a harmful algal bloom) have been observed to accumulate at the landward edge of these density fronts (Garcon et al., 1986~.
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Stratification of the water column acts to restrict mixing and thus prevents the reoxygenation of the depleted subsurface waters (Figures 1-2a and b; Table 1-2~. In severe cases, 4 _ 1 2 -/~)
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(km2) Eutrophication Status Narragansett Bay 4 9.2 91 4,300 Nuisance algal blooms, summer hypoxic and anoxic events Hudson River/ 5.1 6.3 756 41,600 Nuisance algal blooms, Raritan Bay summer hypoxic and anoxic events Chesapeake Bay 64.5 9.4 2,430 166,800 Nuisance and toxic algal blooms, summer hypoxic and anoxic events Mobile Bay 3.3 3 2,246 111,400 Toxic algal blooms, hypoxic and anoxic events Mississippi Rivera 6.9 7 13,150 2,939,900 No nuisance or toxic algal blooms, no hypoxic or anoxic events San Francisco Bay 8.4 6.3 1,966 121,900 Nuisance algal blooms, hypoxic and anoxic events a Large areas of hypoxic and anoxic bottom waters, as well as toxic and nuisance algal blooms, occur in the inner shelf waters downdrift of both the Atchafalaya and Mississippi River deltas.
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From page 32... ...
, based on meteorological pressure fields, has been used to investigate whether this physical feature can be used to predict blooms of toxic algae in this area. In this way, the use of hydrographic data obtained by studying physical processes may someday allow health officials to anticipate outbreaks of harmful algal blooms before the public is exposed to contaminated seafood.
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In drought-stricken areas, higher temperatures change regional rain patterns and affect agricultural productivity, thus disrupting local food supplies. In other areas, climate variability may bring increased rainfall.
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Global Warming, Global Change: Gradual and Abrupt Climate Change Recent weather records reveal that over the past century the climate we have experienced is at least as warm as any century since 1400 AD, possibly due to increases in greenhouse gases. A trend towards a warmer world is emerging from the complex spectrum of natural variability (Nicholls et al., 1995~.
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with lesser warming in western North America, while large regions of the North Pacific and North Atlantic Oceans and their neighboring shores have actually cooled since the 1960s. Many climate variables are affected.
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increase in maximal potential storm intensity for a doubled CO2 climate that is small compared with natural variations (Henderson-Sellers et al., 1998~. However, the continuing rise in sea level, described below, will contribute to the impact of tropical storms through the elevation of the base for storm surges (NRC, 1998a)
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From page 37... ...
Because most of the non-oceanic water is stored in the polar ice sheets, changes in the stability of these sheets could have a significant impact on sea level (Nicholls et al., 1995~. There has been concern that the stability of the West Antarctic Ice Sheet is vulnerable to global warming and may collapse, causing a significant effect on global sea level.
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The Importance of Preparedness of the Health Services The most effective way to reduce the immediate cost in lives and human suffering from a natural disaster caused by a shift in weather patterns as occurs during an E1 Nino, is to improve the promptness and quality of the response of health and medical services. Coastal areas subject to surges, tropical storms, or tsunamis require a higher level of preparedness of both the emergency medical services and the health sector at large.
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Operational research on the cost effectiveness of surveillance techniques and control measures are needed to monitor and respond to disease outbreaks, natural disasters, such as floods and storms, and heat waves. Malaria, dengue, and cholera are increasing pandemics, regardless of any causal effect of the E1 Nino, and even the known effective control measures have yet to be implemented.
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Integration of these new observations into computer models of the ocean and atmosphere improves both predictions and understanding of the underlying dynamics of the system. The nearly exponential increase in computing power over recent decades gives us tools that may soon resolve processes of moderate scalelike regional plankton blooms within the context of a global model of the coupled ocean/atmosphere.
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4. Establish baseline observations of the physical ocean and its ecosystems to monitor global change.
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42 FROM MONSOONS TO MICROBES The next decade will be a crucial period for monitoring climate. The uncertain predictions of climate models will be tested and the changes in the environment may be more striking and heterogeneous than currently predicted.
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