Are more killer heat waves on the horizon

"The top four warmest 12-month periods on record have come in the last six years. The 17 warmest years since record-keeping began in 1867 have occurred since 1980. It is clear that the temperature is rising" and thousands of deaths are the result.

IN AUGUST, 2003, a record heat wave scorched Europe, claiming an estimated 35,000 lives. In France alone, 14,802 people died from the searing temperatures--more than 19 times the death toll from the SARS epidemic worldwide. In the worst heat spell in decades, temperatures in France soared to 104[degrees]F and pretty much stayed in that range for two weeks. During that time, patients suffering from heat-related illnesses lined up for treatment at overcrowded and understaffed hospitals. Paris' morgues were filled past capacity. Excess bodies had to be stored in nearby tents. Those seeking to escape the stifling heat sought out the few public buildings equipped with air conditioning.

Other countries were affected as well. Germany saw some 7,000 perish in the swelter. Spain and Italy each suffered losses of nearly 4,200 lives. At least 1,300 individuals were lost in Portugal and up to 1,400 in the Netherlands.

In London--which on Aug. 10 recorded its first ever triple-digit temperature reading--an estimated 900 citizens were felled. Heat-related fatalities across the United Kingdom reached 2,045. In Belgium, temperatures higher than any in the Royal Meteorological Society's register--dating back to 1833--brought 150 deaths. Since reports are not available for all nations, the actual death toll for the continent likely is higher than what was officially recorded.

Though they rarely are given the same sensational coverage as other natural disasters. heat waves claim more lives each year than floods, tornadoes, and hurricanes combined. In a sense, they are a silent killer, mostly affecting the elderly, very young, or chronically ill. Under normal circumstances, humans maintain a body temperature around 98.6[degrees]F. When subject to extreme heat, the body attempts to maintain this ideal reading by varying blood circulation and perspiring. When the internal temperature rises above 104[degrees], though, vital organs are at risk. If it cannot be reduced, death follows.

The threshold ambient temperature at which more people are at risk for heat-related health complications varies greatly by location. In general, when summer temperatures range 10[degrees] or more above the norm, incidences of heat-related illness--such as heatstroke, hyperthermia, and dehydration--increase dramatically. High humidity compounds the effects of high heat by reducing evaporation, rendering perspiration a less-effective cooling mechanism. When excessive heat prevails for at least three straight days, the risk of illness and death escalates. Health and social services may be overwhelmed.

Heat waves take the greatest human toll in cities. Urban centers, where the area of sizzling dark roofs and pavement exceeds that covered by cooling vegetation, are like "heat islands" and can be as much as 10[degrees] warmer than the surrounding countryside. While rural areas generally see some relief when the thermometer falls at night, urban areas stay warmer around the clock. Air pollution, usually worse in cities, also can exacerbate the effects of scorching temperatures by further stressing the body's respiratory and circulatory systems.

Several of the most severe heat waves have occurred in U.S. cities. In 1955, an eight-day run of 100[degrees]-plus temperatures in Los Angeles left 946 people dead. In 1972, New York City suffered a two-week heat wave that claimed 891 lives. More recently, a 1995 baking in Chicago killed 739 persons in a matter of days. Slow political recognition of the threat and an overloaded response system worsened the effects of the weather anomaly.

The lethality of hot weather

A lack of public recognition on the dangers that high temperatures pose adds to their lethality. Heat-wave warnings often do not carry the weight of other natural disaster alerts. Except during major outbreaks, heat-related deaths often go unreported, and only some governments systematically keep records of them. Moreover, once a heat wave has passed, politicians often are reluctant to acknowledge its toll. Chicago's mayor denied the severity of the city's 1995 tragedy, even as hospitals and funeral homes were pushed past their limits and bodies kept piling up. In Europe, it took more than a month for France's government to release fatality estimates that corroborated the numbers from overwhelmed undertakers. Several neighboring governments still are challenging reports from medical examiners.

Even in India, where heat-related fatalities in the thousands during premonsoonal high temperatures are common, the country's National Disaster Management Cell does not classify heat waves as a natural disaster. While accurate data is hard to come by, it appears that India has seen the number of deaths due to heat climb over the years as populations have grown and temperatures have risen. In May, 2003, peak readings of 113-117[degrees] claimed over 1,600 lives throughout the country. In the state of Andhra Pradesh alone, some 1,200 individuals expired. A year earlier, a one-week heat wave with temperatures topping 122[degrees] took over 1,000 lives.

August, 2003, was the warmest on record in the Northern Hemisphere, but it unlikely will be the last time the region suffers from severely high temperatures. According to the projections of the Intergovernmental Panel on Climate Change, a body of mote than 1,500 scientists from around the world, even more extreme weather events lie ahead as global temperatures keep rising.

The 2003 calendar year was the third warmest on record, according to data from NASA's Goddard Institute for Space Studies. The average temperature was 58.3[degrees], down slightly from the record highs of 58.5[degrees] in 1998 and 58.4[degrees] in 2002, but well above the average 57.2[degrees] that prevailed from 1951 to 1980. The top four warmest 12-month periods on record have come in the last six years. The 17 warmest years since record-keeping began in 1867 have occurred since 1980. It is clear that the temperature is rising--and gaining momentum. Over the last quarter-century, the average global temperature has risen one degree.

By the end of the century, the world's average temperature is projected to jump anywhere from 2.5[degrees] to 10.4[degrees]. As the mercury climbs, more frequent and severe heat waves are in store. This projected rise is a global average, but the temperature is expected to increase more over land, where people live, than over sea. Temperatures also should rise more in higher latitudes than in the equatorial regions. By this logic, America's heartland is well positioned to feel the heat. Not only that, the World Meteorological Organization estimates that the number of heat-related fatalities could double in less than 20 years.

We already are seeing evidence of more frequent heat waves. In India, death tolls that were recorded over an entire summer some 10 years ago now routinely occur in just one week. In the U.S., a 1998 study of summertime temperatures using data from 1949 to 1995 found that the frequency of extremely hot and humid days and the occurrence of multiple-day heat waves jumped significantly during that period. Some of the increase likely is due to urbanization, a trend that is expected to continue.

A warming climate not only means an increase in high-temperature days, but a burgeoning of droughts, flooding, stoma surges, and even cold spells in some areas. Above-normal temperatures can shrivel crops, as evidenced by Europe's reduced grain harvest in 2003. The job of long-term weather forecasters becomes much trickier when the mercury keeps rising and weather patterns are more volatile and unpredictable.

Moreover, higher temperatures are accelerating the melting of ice masses--in the sea and on the continents. The extent of Arctic Ocean ice has shrunk in recent years--2002 and 2003 saw record-low sea ice near the North Pole. The Arctic Ocean could be ice-free by the summer of 2050. On the opposite side of the globe, several ice shelves the size of Delaware (and larger) have crumbled off the coasts of Antarctica in the last five years.

Glaciers in the Himalayan Mountains that feed all the major rivers of Asia are melting at accelerated rates. On Mt. Everest, the glacier that ended at the historic base camp of Sir Edmund Hillary and Tenzing Norgay--the first humans to reach the summit--has retreated three miles since their 1953 ascent. The Antizana Glacier, which provides Quito, Ecuador, with almost half its water, is just one of the many tropical glaciers that is shrinking. Tanzania's Mt. Kilimanjaro could be ice-free by 2020. In the U.S., Glacier National Park soon may need to change its name since it could lose all its glaciers over the next three decades.

Melting glaciers deplete long-term water reservoirs and raise sea levels, putting coastal populations at risk. Rising global temperatures and extra melting alter oceanic circulation, which in turn can cause dramatic and abrupt variations in weather patterns.

Strategic forecasters for the Pentagon have concluded that climate change has profound implications for national security and international stability. Their models indicate that, in the next decade, the number of peak temperature days over 90[degrees] could jump by 30% in most of North America and Europe as well as in parts of South America. Other regions could experience extreme cold and drought. Agricultural production could drop substantially. These are just some of the early-on scenarios that could result in food, water, and energy emergencies. Conflict and unrest likely would follow.

The world must recognize and respond to the threat posed by rapidly rising temperatures. Strong leadership is required. Scientists agree that the burning of fossil fuels is the main contributing factor to the greenhouse effect that is warming the Earth. It is up to us to decide to move away from climate disrupting and polluting fossil fuels like coal, and turn to renewable sources such as solar and wind energy. It is our choice to improve energy efficiency, using already-existing technologies to allow for the closure of outmoded power plants.

Drafting the Kyoto Protocol in 1997 was a first step for governments to recognize the need to reduce carbon emissions. The conference's goal was to cut carbon emissions by an average of five percent from 1990 levels. Yet, while negotiations have stalled in key carbon-emitting nations--namely the U.S. and Russia, one of which would need to sign before the treaty goes into effect--some countries and businesses already have decided that we can go beyond the Kyoto goal (and do so profitably). They realize not only how high the potential cost of inaction of the climate front really is, but what an enormous investment potential that climate change mitigation provides.

Although the historical data for heat waves leave much to be desired, it can be said with confidence that the August, 2003, heat wave in Europe has broken all records for heat-induced human fatalities. As other manifestations of a warming climate unfold, they likely will generate pressure to reduce carbon emissions. Yet, must another tragedy unfold before there is a response? For many of the millions who suffered through these record heat waves and the relatives of the tens of thousands who died, cutting carbon emissions is becoming a pressing personal issue.

Annual Average of
Severe Weather
Fatalities in the U.S.
1993-2002

Lightning      53
Tornado        59
Flood          86
Hurricane      17
Heat Wave   1,500

Source: NOAA, University of Delaware

Note: Table made from bar graph.

Janet Larsen is a research associate at the Earth Policy Institute, Washington, D.C.

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