Global warming is finally being acknowledged as a major environmental issue. Global measurements show that 11 of the last 12 years have been among the warmest observed since 1850. This has led to the melting of the polar ice caps, increased ocean water levels, shorter and warmer winters and the earlier arrival of spring along with the later onset of winter (Salinger et al. 2005; Houghton et al. 2001; Collins et al. 2007). Although, superficially, warmer temperatures may seem like a pleasing side effect for some people, this disruption in the balance of nature can be catastrophic in the long run.
Global warming has occurred mostly due to increased concentrations of greenhouse gases, which include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and chlorofluorocarbons (CFCs). This is down to human activity, particularly the burning of fossil fuels.
One of the many effects that global warming has on our planet is that it will likely lead to increased numbers of structural, agricultural, and forest insect pests. Added to this, numbers of public health pests and insect vectored diseases will rise, due to rising temperatures.
Unbalancing the environment through global warming also drives more extreme weather conditions, leading to long droughts, larger and more frequent storms and increased rainfall; all of which effects plant growth and encourages insects (Easterling et al. 2000; Karl et al. 1995; Stireman et al. 2005). Warm weather pests will be able to start breeding sooner, and for longer, thanks to the milder and shorter winters (Bale et al. 2002), and pests that bear a medical importance – such as mosquitos – will have more of an impact (Hopp and Foley 2001; Epstein 2001).
Warm weather pests that originated in tropical and subtropical climates – such as the Argentine ant (Lithepithema humile), and the red imported fire ant (Solenopsis invicta) – will see a rise in numbers due to increased temperatures. Other pests that will enjoy a warmer climate are: ants, termites, clothes moths, flies, mosquitoes, fleas, stored product moths, wood boring beetles, and even bed bugs. An increase of only 3°C (5.4°F) in temperature may not feel significant to humans but will almost double the growth rate of the German cockroach (Noland et al. 1949), for example.
Warmer temperatures will not only increase the numbers of pests but will also enlarge their geographical range. Formosan subterranean termites, Coptotermes formosanus, are tropical termites that have so far been limited to southern areas due to cold winter temperatures (Potter 1997). With global warming, their range is likely to expand northward. The same applies to various other species of pest, including drywood termites. Currently, they are found mostly on the southern edge of the U.S. and along the Pacific Coast (Potter 1997) but this will probably expand when more areas are able to consistently reach the preferred swarming temperature of about 27°C (80.6°F). Added to that, termites produce considerable amounts of methane, a greenhouse gas. If their numbers and ranges expand, then this will also add to the global warming problem (Thakur et al. 2003).
Climate change directly effects human health. The World Health Organization has estimated that 150,000 deaths are caused each year by drought, floods, air and water pollution and disease resulting from global warming (Patz and Olson 2006). Pathogens for human diseases such as malaria, African trypanosomiasis, Lyme disease, tick-borne encephalitis, yellow fever, plague, and dengue have increased in incidence or geographic range in recent decades (Harvell et al. 2002). Warmer temperatures not only increase mosquito reproduction and biting activity, it also allows the pathogens inside the mosquitoes to mature faster. Texas, Georgia, Florida, Michigan, New Jersey, New York and Toronto have all seen small outbreaks of malaria since 1990 (Epstein 2001; Gil 1920), and the first cases of dengue hemorrhagic fever in the U.S. were seen in Texas late in 2005 (Sci. New 2006).
Global warming definitely means more pests, which not only affects things like plants and crops, but also human welfare, too. The pests that carry and transmit disease are able to breed earlier and for longer due to warmer climates, which means that diseases like malaria are becoming more widespread. Global warming is not a natural phenomenon, it is a problem caused by the actions of humans. With this in mind, it is obvious that the issue can also be solved by human activity. This requires immediate action in order to halt the destruction that we are causing to our own planet.
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