Heat waves are making more and more news each year as they continue to worsen worldwide.
Across the globe we hear of how places in Europe, Australia and the United States suffer for weeks with record setting heat conditions. In many instances, this heat can result in the deaths of several thousand people.
Now scientists are beginning to take a closer look at how these record heat waves are related to global warming.
While it may not be possible to attribute any climatic event solely to global warming, the fact that we are seeing more and more heat events is a cause for concern. According to Anthony Leiserwoitz, Director of the Yale Project on Climate Change, “you can’t say any one heat wave is caused by global warming. But you can say that what global warming does is it makes events just like this more likely.”
Kevin Trenberth, climate analysis branch chief at the National Center for Atmospheric Research in Boulder, Colo, explained that global warming is making the nights warmer and the days drier, and this process in turn intensifies the impact of heat events (they can be quite common), creating extreme heat conditions out of them.
A 2004 computer model showed that as the level of green house gasses rise, by 2040 we could be seeing heat events capable of killing tens of thousands of people at a rate of once every other year. In fact, some scientists argue that with increasing temperatures and increasing population, deaths from extreme heat conditions could triple in major American cities from 2003 to 2050.
Of particular concern is the fact that the nights are warming as well. Nighttime temperatures are important because this is the period the land recovers from the heating in the day. Scientists point to data that shows the number of warm night worldwide has increased while the number of cold nights has declined significantly between 1951 and 2003. According to Daniel C. Esty, a professor of environmental law and policy at Yale University, “the trend lines showing so much hot weather in recent years suggests some concern, even if we can't say definitively this is a signal of climate change.”
The root of a heat wave is a weather pattern known as a high pressure ridge, or an anticyclone.
In these stagnant high pressure air ridges, air from the upper atmosphere sinks and flows outwards. As the air descends, it is compressed, increasing its temperature and degree of dryness. The outflowing air currents also prevent external currents from entering the area, at times leading to persistent and extreme heat conditions. In these situations, the skies are usually clear and cloudless – the sun’s radiation reaches the earth more readily and heats up the land further. The combination of little wind or air movement, low humidity and unobstructed sunlight can heat up the area to temperatures significantly higher than normal, resulting in a heat wave. Longer warm days and shorter cool nights can aggravate the heat situation.
There are numerous impacts of such heat events. One of the biggest concerns is to our health. When the humidity or surrounding temperatures is extremely high, our body is unable to lose heat effectively, heat stroke can set in. Some of the symptoms include lack of sweat, flushed skin, rapid breathing, headaches, and cramps. If not treated, heat stroke can lead to organ failure and even death.
Heat waves can have other impact. With many people trying to cool down and run their air conditioners at the same time, a strain is created on the electricity supplies. As a result, blackouts can occur more frequently, leading to increase in frustrations and overall stress.
Other effects of these heat events include increases in the number of forest fires, that may sometimes become furious and uncontrollable wild fires, and subsequently increase the level of smog. With the stagnant air, smog can lead to serious breathing problems, not only in the more susceptible children and elderly, but also in healthy young people as well.
Read about the other consequences of global warming
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