Many poor nations are expected to suffer even greater health consequences from climate change. In addition, weather and climate extremes such as severe storms and drought can undermine public health infrastructure, further stress environmental resources, destabilize economies, and potentially create security risks both within the United States and internationally.
Some reduction in the risk of death related to extreme cold is expected. Projected Increase in Heat-Related Deaths in Chicago Increases in heat-related deaths are projected in cities around the nation, especially under higher emissions scenarios.
The graph shows the projected number of deaths per year, averaged over a three-decade period around , , and for the City of Chicago under lower and higher emissions.
Temperatures are rising and the probability of severe heat waves is increasing. Analyses suggest that currently rare extreme heat waves will become much more common in the future see National Climate Change. The percentage of the U. Heat-related illnesses range from heat exhaustion to kidney stones. Heat is already the leading cause of weather-related deaths in the United States.
More than 3, deaths between and were reported as resulting from exposure to excessive heat. In , 44 percent of households were without air conditioning, whereas in , only 16 percent of the U. Projections for Chicago suggest that the average number of deaths due to heat waves would more than double by under a lower emissions scenario 6 and quadruple under a high emissions scenario 6 see figure above.
A study of climate change impacts in California projects that, by the s, annual heat-related deaths in Los Angeles would increase by two to three times under a lower emissions scenario and by five to seven times under a higher emissions scenario, compared to a s baseline of about deaths. These estimates assume that people will have become somewhat more accustomed to higher temperatures.
Without such acclimatization, these estimates are projected to be about 20 to 25 percent higher. The full effect of global warming on heat-related illness and death involves a number of factors including actual changes in temperature averages, highs, and lows ; and human population characteristics, such as age, wealth, and fitness.
In addition, adaptation at the scale of a city includes options such as heat wave early warning systems, urban design to reduce heat loads, and enhanced services during heat waves. Urban Heat Island Effect Large amounts of concrete and asphalt in cities absorb and hold heat. Tall buildings prevent heat from dissipating and reduce air flow. At the same time, there is generally little vegetation to provide shade and evaporative cooling.
The researchers found that, on average, cold snaps increased death rates by 1. Many factors contribute to winter deaths, including highly seasonal diseases such as influenza and pneumonia. It is unclear how these diseases are affected by temperature.
In the mids, Philadelphia became the first U. The city focuses its efforts on the elderly, homeless, and poor. During a heat wave, a heat alert is issued and news organizations are provided with tips on how vulnerable people can protect themselves. The health department and thousands of block captains use a buddy system to check on elderly residents in their homes; electric utilities voluntarily refrain from shutting off services for non-payment; and public cooling places extend their hours.
Warming is likely to make it more challenging to meet air quality standards necessary to protect public health. Temperature and Ozone The graphs illustrate the observed association between ground-level ozone a component of smog concentration in parts per billion ppb and temperature in Atlanta and New York City May to October to Ground-level ozone can exacerbate respiratory diseases and cause short-term reductions in lung function.
Half of all Americans, million people, live in counties where air pollution exceeds national health standards. It also increases the incidence of asthma-related hospital visits and premature deaths. As a result, children, outdoor workers, and athletes are at higher risk for these ailments. Projected Change in Ground-Level Ozone, s The maps show projected changes in ground-level ozone a component of smog for the s, averaged over the summer months June through August , relative to , under lower and higher emissions scenarios, which include both greenhouse gases and emissions that lead to ozone formation some of which decrease under the lower emissions scenario.
However, the maps indicate that future projections of ozone depend heavily on emissions, with the higher emissions scenario 6 increasing ozone by large amounts, while the lower emissions scenario 6 results in an overall decrease in ground-level ozone by the end of the century.
Ground-level ozone concentrations are affected by many factors including weather conditions, emissions of gases from vehicles and industry that lead to ozone formation especially nitrogen oxides and volatile organic compounds [VOCs] , natural emissions of VOCs from plants, and pollution blown in from other places.
Under constant pollutant emissions, by the middle of this century, Red Ozone Alert Days when the air is unhealthy for everyone in the 50 largest cities in the eastern United States are projected to increase by 68 percent due to warming alone. Health risks from heat waves and air pollution are not necessarily independent. The formation of ground-level ozone occurs under hot and stagnant conditions — essentially the same weather conditions accompanying heat waves see box in Society sector.
Such interactions among risk factors are likely at least two-thirds chance of occurring to increase as climate change continues. Californians currently experience the worst air quality in the nation. More than 90 percent of the population lives in areas that violate state air quality standards for ground-level ozone or small particles. These pollutants cause an estimated 8, deaths and over a billion dollars in health care costs every year in California.
Because ground-level ozone is related to temperature see Temperature and Ozone figure above , air quality is projected to become worse with human-induced climate change. Many areas in the country already have plans in place for responding to air quality problems. For example, the Air Quality Alert program in Rhode Island encourages residents to reduce air pollutant emissions by limiting car travel and the use of small engines, lawn mowers, and charcoal lighter fluids on days when ground-level ozone is high.
Television weather reports include alerts when ground-level ozone is high, warning especially susceptible people to limit their time outdoors. To help cut down on the use of cars, all regular bus routes are free on Air Quality Alert days. Traffic restrictions imposed during the summer Olympics in Atlanta quantified the direct respiratory health benefits of reducing the number of cars and the amount of their tailpipe emissions from an urban environment.
Peak morning traffic decreased by 23 percent, and peak ozone levels dropped by 28 percent. As a result, childhood asthma-related emergency room visits fell by 42 percent.
Extreme weather events cause physical and mental health problems. Some of these events are projected to increase. Injury, illness, emotional trauma, and death are known to result from extreme weather events. For example, early warning and evacuation systems and effective sanitation lessen the health impacts of extreme events. This assumes that medical and emergency relief systems in the United States will function well and that timely and effective adaptation measures will be developed and deployed.
There have already been serious failures of these systems in the aftermath of hurricanes Katrina and Rita, so coping with future impacts will require significant improvements. Extreme storms Over 2, Americans were killed in the hurricane season, more than double the average number of lives lost to hurricanes in the United States over the previous 65 years.
Floods Heavy downpours have increased in recent decades and are projected to increase further as the world continues to warm. Over the last century, there was a 50 percent increase in the frequency of days with precipitation over 4 inches in the upper Midwest. Heavy rains can lead to flooding, which can cause health impacts including direct injuries as well as increased incidence of waterborne diseases due to pathogens such as Cryptosporidium and Giardia.
The consequences will be particularly severe in the roughly U. In , the Environmental Protection Agency EPA established a policy that mandates that communities substantially reduce or eliminate their combined sewer overflow, but this mandate remains unfulfilled. Using 2. Higher water temperatures and ocean acidification due to increasing atmospheric carbon dioxide will present major additional stresses to coral reefs, resulting in significant die-offs and limited recovery.
Calcium Carbonate Saturation in Ocean Surface Waters Corals require the right combination of temperature, light, and the presence of calcium carbonate which they use to build their skeletons. As atmospheric carbon dioxide levels rise, some of the excess carbon dioxide dissolves into ocean water, reducing its calcium carbonate saturation. As the maps indicate, calcium carbonate saturation has already been reduced considerably from its pre-industrial level, and model projections suggest much greater reductions in the future.
The blue dots indicate current coral reefs. Note that under projections for the future, it is very unlikely that calcium carbonate saturation levels will be adequate to support coral reefs in any U. Since the beginning of the industrial era, ocean pH has declined demonstrably and is projected to decline much more by if current emissions trends continue. Further declines in pH are very likely to continue to affect the ability of living things to create and maintain shells or skeletons of calcium carbonate.
This is because at a lower pH less of the dissolved carbon is available as carbonate ions see Global Climate Change. Ocean acidification will affect living things including important plankton species in the open ocean, mollusks and other shellfish, and corals.
Coral calcification rates are likely to decline by more than 30 percent under a doubling of atmospheric carbon dioxide concentrations, with erosion outpacing reef formation at even lower concentrations. The upwelling of deeper ocean water, deficient in carbonate, and thus potentially detrimental to the food chains supporting juvenile salmon has recently been observed along the U. West Coast. Acidification imposes yet another stress on reef-building corals, which are also subject to bleaching — the expulsion of the microscopic algae that live inside the corals and are essential to their survival — as a result of heat stress 25 see Ecosystems sector and Islands region.
As a result of these and other stresses, the corals that form the reefs in the Florida Keys, Puerto Rico, Hawaii, and the Pacific Islands are projected to be lost if carbon dioxide concentrations continue to rise at their current rate.
Pacific Coast Dead Zones Climate change affects coastal currents that moderate ocean temperatures and the productivity of ecosystems.
Climate change is expected to affect such coastal currents, and possibly the larger scale natural oscillations as well, though these effects are not yet well understood. The recent emergence of oxygen-depletion events on the continental shelf off Oregon and Washington a dead zone not directly caused by agricultural runoff and waste discharges such as those in the Gulf of Mexico or Chesapeake Bay is one example.
Adaptation to sea-level rise is already taking place in three main categories: 1 protecting the coastline by building hard structures such as levees and seawalls although hard structures can, in some cases, actually increase risks and worsen beach erosion and wetland retreat , 2 accommodating rising water by elevating or redesigning structures, enhancing wetlands, or adding sand from elsewhere to beaches the latter is not a permanent solution, and can encourage development in vulnerable locations , and 3 planned retreat from the coastline as sea level rises.
Several states have laws or regulations that require setbacks for construction based on the planned life of the development and observed erosion rates. Governments and private interests are beginning to take sea-level rise into account in planning levees and bridges, and in the siting and design of facilities such as sewage treatment plants see Adaptation box in Northeast region.
Global Change Research Program Legacy site. Adaptation Regional Adaptation Sectoral Adaptation. Table of Contents. Multiple Stresses Confront Coastal Regions Various forces of climate change at the coasts pose a complex array of management challenges and adaptation requirements.
Adaptation: Coping with Sea-Level Rise Adaptation to sea-level rise is already taking place in three main categories: 1 protecting the coastline by building hard structures such as levees and seawalls although hard structures can, in some cases, actually increase risks and worsen beach erosion and wetland retreat , 2 accommodating rising water by elevating or redesigning structures, enhancing wetlands, or adding sand from elsewhere to beaches the latter is not a permanent solution, and can encourage development in vulnerable locations , and 3 planned retreat from the coastline as sea level rises.
0コメント