Generation Us by Andrew Weaver

Author:Andrew Weaver
Language: eng
Format: epub
Tags: SCI092000
Publisher: Orca Book Publishers
Published: 2011-05-03T16:00:00+00:00

GLOBAL WARMING AND OUR HEALTH

Global warming is projected to have both positive and negative effects on human health. Summer heat-related mortalities are expected to increase. An extreme example of this occurred in Europe during August 2003. Thirty-five thousand people died from heat-related causes. At the same time, the number of deaths from exposure to cold in the winter is expected to decrease.

When and where infectious disease outbreaks occur will also be affected by global warming. The negative effects will be largest in some of the poorest, less-developed parts of the world. These same regions already struggle with a higher incidence of infectious diseases than North America. Some infectious diseases will expand into new areas. Warming temperatures in North America could lead to a reduction in the occurrence of respiratory diseases such as the flu and pneumonia.

West Nile virus was first discovered in Uganda in 1937. This tropical disease entered the United States in 1999. By 2010 it had firmly taken hold throughout the continental United States and southern Canada. Warming temperatures and the earlier arrival of spring have been implicated in the cause of the outbreak. Another mosquito-borne disease that will likely move northward is dengue fever. This nasty and sometimes fatal illness showed up in Florida in 2010. Outbreaks occasionally occur on the Texas border with Mexico.

Lyme disease, carried by ticks, is also becoming more common as the climate warms. Cold winter temperatures are needed to kill off the ticks. Lyme disease should become well established in southern and eastern Canada in the years ahead. It is already firmly entrenched in British Columbia.

Many water- and food-borne diseases are also susceptible to changing climate. Increasing extreme precipitation and subsequent flooding has led to outbreaks of cholera in parts of Africa. Closer to home, E. coli outbreaks have been linked to extreme precipitation events. For example, 5.3 inches (134 millimeters) of rain fell at Walkerton, Ontario, over a five-day period from May 8 to May 12, 2000. Of this, 2.8 inches (70 millimeters) fell on May 12. A total of 2321 people became ill, and seven eventually died from an E. coli outbreak caused by the runoff from farms infiltrating the water supply. Among other diseases, Salmonella is a type of bacteria that can lead to food poisoning. It is known to reproduce more rapidly in warmer conditions.

One of the consequences of global warming for Canada and the northern United States is that precipitation will come in fewer, more extreme events, interspersed with longer periods of little or no precipitation. Extended dry periods allow tiny particles, including pollen and pollution, to remain in the air longer. As a result, the incidence of asthma, allergies and hay fever will likely increase. In 1999, a tropical fungus, Cryptococcus gattii, was found to have established itself in some soils and trees on Vancouver Island. Previously it only existed in places like Australia and Papua New Guinea. Since 1999, the fungus has spread, and a new strain has emerged in Oregon and Washington state. Humans are affected when its spores are inhaled.

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