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Concern over the potential impacts of climate change led South Carolina Governor Mark Sanford to issue an Executive Order on February 16, 2007 to create a Climate, Energy and Commerce Advisory Committee tasked with developing an Action Plan for the state of South Carolina in order to mitigate carbon dioxide emissions. Governor Sanford cited as a need for such action the “potential effects of global climate change…including more frequent and severe storm events and flooding; sea level rise, water supply disruption, agricultural crop yield changes and forest productivity shifts; water and air quality degradation; and threats to coastal areas, tourism, and infrastructure – could significantly impact South Carolina’s economy, level of public expenditures, and quality of life.”
In the Preamble to the Executive Order, Governor Sanford cited as an example of the impacts of a changing climate his personal observations of changes in the forest line of his Beaufort County farm and the burdensome levels of smog in the air during a recent visit he made to Beijing, China. Together with a collection of scientific reports, this information led him to become concerned with the impacts of human activities on the climate of the earth, and more specifically, on the climate of South Carolina. However, had he taken a broader look at the history of the climate and climate impacts in the state he governs, he would have found out that on average, temperatures in South Carolina are little different now, than during the first half of the 20th century, that the state receives about the same average amount of precipiation now as it did then, that major droughts have become less severe, that agriculture yields are rising, forest industry development and investment are a record levels, and that the tourism industry is strong and growing. Additionally, there has been no trend in hurricanes landfalls, intensity, or impacts, and the rate of sea level rise along the coast has been relatively constant and for more than 100 years and dominated by land subsidence and natural processes rather than anthropogenic global warming.
Further, no action by South Carolina will have any detectable effect on the future rate of global climate change and/or its impacts on the climate of South Carolina.
Observed Climate Change in South Carolina
THERE IS no observational evidence of unusual long-term climate changes in South Carolina. No emissions reductions by South Carolina will have any detectable regional or global effect whatsoever on climate change.
Annual temperature: The historical time series of statewide annual temperatures in South Carolina begins in 1895. Over the entire record, there is no statistically significant trend. Instead, the record is dominated annual and decadal-scale variability. Despite a slight warming trend during the past 30 years, the statewide average temperature still largely remains at or below the average temperature during the first half of the 20th century.
South Carolina Annual Temperatures, 1895-2007
Annual mean temperatures
Figure 1. South Carolina statewide annual average temperature history, 1895-2007. The state’s temperature history is better characterized by multidecadal variations than by a long-term trend (source: National Climatic Data Center, http://www.ncdc.noaa.gov/oa/climate/research/cag3sc.html).
Seasonal temperatures: Likewise, there are no statistically significant long-term seasonal temperature trends evident across South Carolina. Instead, year-to-year and/or decade-to-decade variability is most obvious. In no season do recent temperatures appear unusual compared with observed temperature history. There is no evidence of “climate change.”
South Carolina’s Seasonal Temperatures, 1895-2007
Seasonal mean temperatures
Figure 2. Seasonal statewide average temperature history of South Carolina (source: National Climatic Data Center, http://www.ncdc.noaa.gov/oa/climate/research/cag3sc.html).
Precipitation: As with temperature, there is no statistically significant overall trend in total annual precipitation averaged across South Carolina. Instead the record is dominated by large interannual variations—ranging from over 70 inches of precipitation in 1964 to under 33 inches in 1954. Despite the dry year of 2007, overall, recent years are not unusual when viewed against the long-term history.
South Carolina Annual Precipitation, 1895-2007
Total annual precipitation
Figure 3. South Carolina statewide average annual total precipitation history, 1907-2006 (Data Source: National Climatic Data Center, http://www.ncdc.noaa.gov/oa/climate/research/cag3/sc.html). The statewide precipitation history is better characterized by large interannual variations than any long-term trend.
Drought: As can be surmised from the state’s long-term precipitation history, during the past 113 years of record keeping, there has been no long-term trend in statewide incidence of drought in South Carolina.
South Carolina Drought History, 1895-2007
Palmer Drought Severity Index (PDSI)
Figure 4. South Carolina statewide average monthly Palmer Drought Severity Index (PDSI), 1907-2007 (Data Source: National Climatic Data Center).
According to records compiled by the National Climatic Data Center, statewide monthly average Palmer Drought Severity Index values—a standard measure of moisture conditions that takes into account both inputs from precipitation and losses from evaporation—show no long-term trend during the past 100 years. The period of record is dominated by short term variations, although some longer-term signals are present, such as the extended period of drought in the late 1920s and again in the mid-1950s. The incidence and duration of extreme drought has typically been less in the latter half of the past century than it was during the early half.
Crop Yields: In South Carolina, the annual yields from crops such as cotton, corn and soybeans have risen dramatically during the past 80 years (USDA), while the climate there has changed relatively little. This indicates that factors other than climate are largely responsible for the rapid yield rise.
South Carolina Crop Yields, 1926-2007
Figure 5. History of crop yields (1926-2007) of three economically significant crops in South Carolina, cotton (top), corn (middle), soybeans (bottom). There is no indication that long-term climate changes are negatively impacting crop yields.
Crop yields increase primarily as a result of technology—better fertilizer, more resistant crop varieties, improved tilling practices, modern equipment, and so on. The level of atmospheric carbon dioxide, a constituent that has proven benefits for plants, has increased as well. The relative influence of weather is minimal compared with those advances. Temperature and precipitation show only weak or non-existent long-term trends; they are instead responsible for some of the year-to-year variation in crops yields about the long-term upward trend. Even under the worst of circumstances, minimum crop yields continue to increase. Through the use of technology, farmers are adapting to the climate conditions that traditionally dictate what they do and how they do it and producing more output than ever before. There is no reason to think that such adaptations and advances will not continue into the future. Thus, projections of negative impacts to South Carolina’s agriculture that may result from climate change are unfounded.
Hurricanes: Despite the recent increase in hurricane frequency and intensity in the Atlantic Ocean, the number of hurricanes affecting South Carolina shows no long-term trend, but instead shows multi-decadal variability.
South Carolina Hurricane Landfalls, 1900-2007
Figure 6. Landfalling hurricanes in South Carolina, 1900-2007. Category 1 and 2 storms are indicated by blue bars, category 3 or higher storms are indicated by red bars and are labeled.
Since 1900, 16 hurricanes have made direct landfall in South Carolina. Four of these storms have been major hurricanes (category 3 or higher)—1906 (cat 3), Hazel (1954, cat. 4), Gracie (1959, cat. 3) and Hugo (1989, cat. 4). There have been only 5 hurricanes that have made landfall in South Carolina during the past 48 years.
Since 1995 there has been an increase in both the frequency and intensity of tropical storms and hurricanes in the Atlantic basin at large. While some scientists have attempted to link this increase to anthropogenic global warming, others have pointed out that Atlantic hurricanes exhibit long-term cycles, and that this latest upswing is simply a return to conditions that characterized earlier decades in the 20th century.
One prominent scientist who has been trying to place the current hurricane activity in the longer term perspective is the University of South Carolina’s Dr. Cary Mock. In 2005, Dr. Mock was the recipient of a $300,000 grant from the National Science Foundation to reconstruct the hurricane history of the U. S. from historic archives (newspapers, diaries, ships logs, etc.). The grant will allow him to expand his emphasis from South Carolina to the entire U.S. and Caribbean Atlantic and Gulf shorelines. In his work to date, Dr. Mock has found that there have marked variations in the multi-decadal frequencies of Atlantic tropical storms and hurricanes dating back into the 1700s. In South Carolina, in particular, Dr. Mock finds that there have been several periods in that past 200-300 years during which the state has been impacted (both in terms of frequency and intensity) by tropical cyclones to a greater degree than they have been during recent decades. These active periods include the first half of the 19th century, a multi-decadal period centered about 1900 and again from the mid-1940 to the mid-1960s. These periods of enhanced activity occurred despite the fact that global average temperatures were cooler then than they are currently and demonstrate that there are many processes besides global temperatures that act to influence South Carolina’s vulnerability to tropical cyclones.
Figure 7. Reconstructed tropical cyclone frequencies (top) and hurricane frequencies (bottom) for South Carolina from 1769-2003. Thick lines represent centered 10-year running frequencies. Vertical bars represent annual frequencies with respect to the right axes. In the bottom graph, category 3 hurricanes are represented by arrows and the years listed. The historical record is dominated by multi-decadal variability and does not exhibit a long-term trend (Source, Mock et al. 2004).
Dr. Mock’s research indicates that the strongest storm ever to hit South Carolina probably occurred in September 1752, when records kept by the British Royal Navy indicate that a strong category 4 storm blew ashore. Also, Dr. Mock has determined that during a 20 year period in the early 1800s, three category 3 storms hit the state, two came ashore near Charleston, and the third near Georgetown. Based upon these past frequencies, Dr. Mock is of the opinion that South Carolina’s coastline is naturally “long overdue” for a direct hit from a major hurricane.
And when the next major hurricane hits South Carolina, it will encounter a state whose population demographics have changed quite a bit since the last major storm impact. A direct strike from a major hurricane (or any hurricane for that matter) will likely lead to more damage and destruction now that it did in the past. While this gives the impression that storms are getting worse, in fact, it simply may be that there are a greater number of assets that lie in their path. New research by a team of researchers led by Dr. Roger Pielke Jr. (2007) sheds some light on how population changes underlay hurricane damage statistics. Dr. Pielke’s research team examined the historical damage amounts from tropical cyclones in the United States from 1900 to 2005. What they found when they adjusted the reported damage estimates only for inflation was a trend towards increased amounts of loss, peaking in the years 2004 and 2005, which include Hurricane Katrina as the record holder for the most costliest storm, causing 81 billion dollars in damage.
Total U.S. Losses from Atlantic Tropical Cyclones, 1900-2005
Figure 8. U.S. tropical cyclone damage (in 2005 dollars) when adjusted for inflation, 1900-2005 (from Pielke Jr., et al., 2007)
However, many changes have occurred in hurricane prone areas since 1900 besides inflation. These changes include a coastal population that is growing in size as well as wealth. When the Pielke Jr. team made adjustments considering all three factors, they found no long-term change in damage amounts. And, in fact, the loss estimates in 2004 and 2005, while high, were not historically high. The new record holder, for what would have been the most damaging storm in history had it hit in 2005, was the Great Miami hurricane of 1926, which they estimated would have caused 157 billion dollars worth of damage. After the Great Miami hurricane and Katrina (which fell to second place), the remaining top-ten storms (in descending order) occurred in 1900 (Galveston 1), 1915 (Galveston 2), 1992 (Andrew), 1983 (New England), 1944 (unnamed), 1928 (Lake Okeechobee 4), 1960 (Donna/Florida), and 1969 (Camille/Mississippi). There is no obvious bias towards recent years. In fact, the combination of the 1926 and 1928 hurricanes places the damages in 1926-35 nearly 15% higher than 1996-2005, the last decade Pielke Jr. and colleagues studied.
Normalized Losses from Atlantic Tropical Cyclones, 1900-2005
Figure 9. U.S. tropical cyclone damage (in 2005 dollars) when adjusted for inflation, population growth and wealth, 1900-2005 (from Pielke Jr., et al., 2007).
This result by the Pielke Jr. team, that there has not been any long-term increase in tropical cyclone damage in the United States, is consistent with other science concerning the history of Atlantic hurricanes. One of Dr. Pielke co-authors, Dr. Chris Landsea, from the National Hurricane Center, has also found no trends in hurricane frequency or intensity when they strike the U.S. While there has been an increase in the number of strong storms in the past decade, there were also a similar number of major hurricanes in the 1940s and 1950s, long before such activity could be attributed to global warming.
As Pielke writes, “The lack of trend in twentieth century hurricane losses is consistent with what would expect to find given the lack of trends in hurricane frequency or intensity at landfall.”
Even in the absence of any long-term trends in hurricane landfalls along the South Carolina or the U.S. coast, or damage to U.S. coastlines when population demographics are taken into account, the impact from a single storm, such as 1989’s Hurricane Hugo, can be enormous as residents of South Carolina know well. The massive build-up of the coastline has vastly raised the potential damage that a storm can inflict. Recently, a collection of some of the world’s leading hurricane researchers issued the following statement that reflects the current thinking on hurricanes and their potential impact (http://wind.mit.edu/~emanuel/Hurricane_threat.htm):
As the Atlantic hurricane season gets underway, the possible influence of climate change on hurricane activity is receiving renewed attention. While the debate on this issue is of considerable scientific and societal interest and concern, it should in no event detract from the main hurricane problem facing the United States: the ever-growing concentration of population and wealth in vulnerable coastal regions. These demographic trends are setting us up for rapidly increasing human and economic losses from hurricane disasters, especially in this era of heightened activity. Scores of scientists and engineers had warned of the threat to New Orleans long before climate change was seriously considered, and a Katrina-like storm or worse was (and is) inevitable even in a stable climate.
Rapidly escalating hurricane damage in recent decades owes much to government policies that serve to subsidize risk. State regulation of insurance is captive to political pressures that hold down premiums in risky coastal areas at the expense of higher premiums in less risky places. Federal flood insurance programs likewise undercharge property owners in vulnerable areas. Federal disaster policies, while providing obvious humanitarian benefits, also serve to promote risky behavior in the long run.
We are optimistic that continued research will eventually resolve much of the current controversy over the effect of climate change on hurricanes. But the more urgent problem of our lemming-like march to the sea requires immediate and sustained attention. We call upon leaders of government and industry to undertake a comprehensive evaluation of building practices, and insurance, land use, and disaster relief policies that currently serve to promote an ever-increasing vulnerability to hurricanes.
However, all impacts from tropical cyclones in South Carolina are not negative. In fact, precipitation that originates from tropical systems and that eventually falls in South Carolina proves often to be quite beneficial to the state’s agriculture industry. The late summer months is the time during the year when, climatologically, the precipitation deficit is the greatest and crops and other plants are the most moisture stressed. A passing tropical cyclone often brings much needed precipitation over large portions of the state during these late summer months. In fact, recent research shows that South Carolina, on average, receives about 25% percent of its normal September precipitation, and about 10 to15 percent of its total June through November total precipitation from passing tropical systems. And since more than 90% of South Carolina’s field crops such as corn, cotton, and soybeans are grown under non-irrigated conditions, widespread rainfall from a tropical cyclone becomes almost an expected and relied upon late summer moisture source.
Figure 10. Percentage of June through November precipitation that comes from tropical systems (Knight and Davis, 2007).
Sea Level Rise: Over the course of the last century or so, South Carolina’s coastline has experienced a relative sea-level rise of about 10 to 12 inches from a combination of land subsidence and actual rising seas. This rise is similar to the rise that is expected to occur there during the next 50 to 100 years as a result of global climate changes resulting from an enhancing greenhouse effect.
The relative sea level along the South Carolina coast has changed due to a combination of the land slightly sinking the ocean slightly rising (Aubrey and Emery, 1991; South Carolina Sea Grant Consortium, 2007). Over time, the sediments that have been washed down from upland areas and that underlie South Carolina’s coastal region slowly compact under their own weight. Additionally, the damming of rivers and the widespread building of revetments and bulkheads along tidal streams and marshes acts to effectively prohibit new sediment from being carried into the coastal wetlands and replenishing the compacting ground. Together, these processes have led to subsidence of coastal South Carolina, and they drive a relative sea level rise. Acting on top of the sinking of the land, is a rise in global sea level from a combination of natural cycles and warming seas. Yet, despite this slowly rising level of the oceans, South Carolina’s residents have successfully adapted, as the growing population of coastal South Carolina attests.
The latest projections of future sea level rise, as given in the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), suggest a potential sea level rise in the coming century of between 7 and 23 inches, depending of the total amount of warming that occurs. The IPCC links a lower sea level rise with lower future warming. The established warming rate of the earth is 0.18ºC per decade, which is near the low end of the IPCC range of projected warming for the 21st century which is from 0.11 to 0.64ºC per decade. Therefore, since we observe that the warming rate is tracking near the low end of the IPCC projections, we should also expect that the rate of sea level rise should track near the low end of the range given by the IPCC—in this case, a future rise much closer to 7 inches than to 23 inches. Thus, the reasonably expected rate of sea level rise in the coming decades is not much different to the rate of sea level rise that South Carolina coastlines have been experiencing for more than a century—and have adapted to.
Projected Global Sea Level Rise 2000-2100
Figure 11. Range of sea level rise projections (and their individual components) for the year 2100 made by the IPCC AR4 for its six primary emissions scenarios.
There are a few individuals who argue that sea level rise will accelerate precipitously in the future and raise the level of the ocean to such a degree that it inundates portions of coastal South Carolina and other low-lying areas around the world and they clamor that the IPCC was far too conservative in its projections. However, these rather alarmist views are not based upon the most reliable scientific information, and in fact, ignore what our best understanding of how a warmer world will impact ice loss/gain on Greenland and Antarctica and correspondingly, global sea level. It is a fact, that all of the extant models of the future of Antarctica indicate that a warmer climate leads to more snowfall there (the majority of which remains for hundreds to thousands of years because it is so cold) which acts to slow the rate of global sea level rise (because the water remains trapped in ice and snow). And new data suggest that the increasing rate of ice loss from Greenland observed over the past few years has started to decline (Howat et al., 2007). Scenarios of disastrous rises in sea level are predicated on Antarctica and Greenland losing massive amounts of snow and ice in a very short period of time—an occurrence with virtual zero likelihood.
In fact, an author of the IPCC AR4 chapter dealing with sea level rise projections, Dr. Richard Alley, recently testified before the House Committee on Science and Technology concerning the state of scientific knowledge of accelerating sea level rise and pressure to exaggerate what it known about it. Dr. Alley told the Committee:
This document [the IPCC AR4] works very, very hard to be an assessment of what is known scientifically and what is well-founded in the refereed literature and when we come up to that cliff and look over and say we don’t have a foundation right now, we have to tell you that, and on this particular issue, the trend of acceleration of this flow with warming we don’t have a good assessed scientific foundation right now. [emphasis added]
Thus the IPCC projections of future sea level rise, which average only about 15 inches for the next 100 years, stand as the best projections that can be made based upon our current level of scientific understanding. These projections are far less severe that the alarming projections of many feet of sea level rise that have been made by a few individuals whose views lie outside of the scientific consensus.
Heatwaves: The population of South Carolina has likely become less sensitive to the impacts of excessive heat events over the course of the past 30-40 years. This is true in most major cities across the United States—a result of the increased availability and use of air-conditioning and the implementation of social programs aimed at caring for high-risk individuals—despite rising urban temperatures.
Heat-related mortality trends across the U.S.
Figure 12. Annual heat-related mortality rates (excess deaths per standard million population). Each histogram bar indicates a different decade (from left to right, 1970s, 1980s, 1990s). (Source: Davis et al., 2003b).
A number of studies have shown that during the several decades, the population in major U.S. cities has grown better adapted, and thus less sensitive, to the effects of excessive heat events (Davis et al., 2003ab). Each of the bars of the illustration above represents the annual number of heat-related deaths in 28 major cities across the United States. There should be three bars for each city, representing, from left to right, the decades of the 1970s, 1980s and 1990. For nearly all cities, the number of heat-related deaths is declining (the bars are get smaller). And although there are no cities from South Carolina that were included in the Davis et al. studies, in most cities in states in the southern and southeastern United States that were part of the investigation, there is not a bar present at all in the 1990s (see for instance, the closest city to South Carolina included in the studies, Charlotte, North Carolina, indicated by CHL in the figure above). This indicates that there are no statistically distinguishable heat-related deaths during that decade (the most recent one studied)—meaning that the population of those cities has become nearly completely adapted to heat waves. This is likely to be the case in South Carolina cities as well, as these cities share characteristics of the climate of those of the cities noted above. This adaptation is most likely a result of improvements in medical technology, access to air-conditioned homes, cars, and offices, increased public awareness of potentially dangerous weather situations, and proactive responses of municipalities during extreme weather events.
The pattern of the distribution of heat-related mortality shows that in locations where extremely high temperatures are more commonplace, such as along the southern tier states, the prevalence of heat-related mortality is much lower than in the regions of the country where extremely high temperatures are somewhat rarer (e.g. the northeastern U.S.). This provides another demonstration that populations adapt to their prevailing climate conditions. If temperatures warm in the future and excessive heat events become more common, there is every reason to expect that adaptations will take place to lessen their impact on the general population.
Vecter-borne Diseases: “Tropical” diseases such as malaria and dengue fever have been erroneously predicted to spread due to global warming. In fact, they are related less to climate than to living conditions. These diseases are best controlled by direct application of sound, known public health policies.
Malaria Distribution in the United States
Figure 13. Shaded regions indicate locations where malaria was endemic in the United States (from Zucker et al., 1996).
The two tropical diseases most commonly cited as spreading as a result of global warming, malaria and dengue fever, are not in fact “tropical” at all and thus are not as closely linked to climate as many people suggest. For example, malaria epidemics occurred as far north as Archangel, Russia, in the 1920s, and in the Netherlands. Malaria was common in most of the United States prior to the 1950s (Reiter, 1996). In fact, in the late 1800s, a period when it was demonstrably colder in the United States than it is today, malaria was endemic in most of the United States east of the Rocky Mountains—a region that includes most of the (non-mountainous portions) of South Carolina. In 1878, about 100,000 Americans were infected with malaria; about one-quarter of them died. By 1912, malaria was already being brought under control, yet persisted in the southeastern United States well into the 1940s. In fact, in 1946 the Congress created the Communicable Disease Center (the forerunner to the current U.S. Centers for Disease Control and Prevention) for the purpose of eradicating malaria from the regions of the U.S. where it continued to persist. By the mid-to-late 1950s, the Center had achieved its goal and malaria was effectively eradicated from the United States. This occurred not because of climate change, but because of technological and medical advances. Better anti-malaria drugs, air-conditioning, the use of screen doors and windows, and the elimination of urban overpopulation brought about by the development of suburbs and automobile commuting were largely responsible for the decline in malaria (Reiter, 1996; Reiter, 2001). Today, the mosquitoes that spread malaria are still widely present in the United States, but the transmission cycle has been disrupted and the pathogen leading to the disease is absent. Climate change is not involved.
U.S. Mortality Rates From Malaria, 1900-1949
Figure 14. Mortality rate in the United States from malaria (deaths per 100,000) from 1900 to 1949, when it was effectively eradicated from the country. (http://www.healthsentinel.com/graphs.php?id=4&event=graphcats_print_list_item)
The effect of technology is also clear from statistics on dengue fever outbreaks, another mosquito-borne disease. In 1995, a dengue pandemic hit the Caribbean and Mexico. More than 2,000 cases were reported in the Mexican border town of Reynosa. But in the town of Hidalgo, Texas, located just across the river, there were only seven reported cases of the disease (Reiter, 1996). This is just not an isolated example, for data collected over the past several decades has shown a similarly large disparity between the high number of cases of the disease in northern Mexico and the rare occurrences in the southwestern United States (Reiter, 2001). There is virtually no difference in climate between these two locations, but a world of difference in infrastructure, wealth, and technology—city layout, population density, building structure, window screens, air-conditioning and personal behavior are all factors that play a large role in the transmission rates (Reiter, 2001).
Dengue Fever at the Texas/Mexico border from 1980 to 1999
Figure 15. Number of cases of Dengue Fever at the Texas/Mexico border from 1980 to 1999. During these 20 years, there were 64 cases reported in all of Texas, while there were nearly 1,000 times that amount in the bordering states of Mexico (Figure from Reiter, 2001).
Another “tropical” disease that is often (falsely) linked to climate change is the West Nile Virus. The claim is often made that a warming climate is allowing the mosquitoes that carry West Nile Virus to spread into South Carolina. However, nothing could be further from the truth.
West Nile Virus was introduced to the United States through the port of New York City in the summer of 1999. Since its introduction, it has spread rapidly across the country, reaching the West Coast by 2002 and has now been documented in every state as well as most provinces of Canada. This is not a sign that the U.S. and Canada are progressively warming. Rather, it is a sign that the existing environment is naturally primed for the virus.
Spread of the West Nile Virus across the United States after its Introduction in New York City in 1999
Figure 16. Spread of the occurrence of the West Nile Virus from its introduction to the United States in 1999 through 2007. By 2003, virtually every state in the country had reported the presence of virus. (source: http://www.cdc.gov/ncidod/dvbid/westnile/Mapsactivity/surv&control07Maps.htm).
The vector for West Nile is mosquitoes; wherever there is a suitable host mosquito population, an outpost for West Nile virus can be established. And it is not just one mosquito species that is involved. Instead, the disease has been isolated in over 40 mosquito species found throughout the United States. So the simplistic argument that climate change is allowing a West Nile carrying mosquito species to move into South Carolina is simply wrong. The already-resident mosquito populations of South Carolina are appropriate hosts for the West Nile virus—as they are in every other state.
Clearly, as is evident from the establishment of West Nile virus in every state in the contiguous U.S., climate has little, or nothing, to do with its spread. The annual average temperature from the southern part of the United States to the northern part spans a range of more than 40ºF, so clearly the virus exists in vastly different climates. In fact, West Nile virus was introduced in New York City—hardly the warmest portion of the country—and has spread westward and southward into both warmer and colder and wetter and drier climates. This didn’t happen because climate changes allowed its spread, but because the virus was introduced to a place that was ripe for its existence—basically any location with a resident mosquito population (which describes basically anywhere in the U.S).
West Nile virus now exists in South Carolina because the extant climate/ecology of South Carolina is one in which the virus can thrive. The reason that it was not found in South Carolina in the past was simply because it had not been introduced. Climate change in South Carolina, which is demonstrably small compared to the natural variability of the state’s climate history, has absolutely nothing to do with it. By following the virus’ progression from 1999 through 2007, one clearly sees that the virus spread from NYC southward and westward, it did not invade slowly from the (warmer) south, as one would have expected if warmer temperatures was the driver.
Since the disease spreads in a wide range of both temperature and climatic regimes, one could raise or lower the average annual temperature in South Carolina by many degrees or vastly change the precipitation regime and not make a bit of difference in the aggression of the West Nile Virus. Science-challenged claims to the contrary are not only ignorant but also dangerous, serving to distract from real epidemiological diagnosis which allows health officials critical information for protecting the citizens of South Carolina.
Impacts of climate-mitigation measures in South Carolina
Globally, in 2003, humankind emitted 25,780 million metric tons of carbon dioxide (mmtCO2: EIA, 2007a), of which South Carolina accounted for 79.2 mmtCO2, or only 0.3% (EIA, 2007b). The proportion of manmade CO2 emissions from South Carolina will decrease over the 21st century as the rapid demand for power in developing countries such as China and India outpaces the growth of South Carolina’s CO2 emissions (EIA, 2007b).
During the past 5 years, global emissions of CO2 from human activity have increased at an average rate of 3.5%/yr (EIA, 2007a), meaning that the annual increase of anthropogenic global CO2 emissions is more than 10 times greater than South Carolina’s total emissions. Even a complete cessation of all CO2 emissions in South Carolina will be undetectable globally. A fortiori, regulations prescribing a reduction, rather than a complete cessation, of South Carolina’s CO2 emissions will have no effect on global climate.
Wigley (1998) examined the climate impact of adherence to the emissions controls agreed under the Kyoto Protocol by participating nations, and found that, if all developed countries meet their commitments in 2010 and maintain them through 2100, with a mid-range sensitivity of surface temperature to changes in CO2, the amount of warming “saved” by the Kyoto Protocol would be 0.07°C by 2050 and 0.15°C by 2100. The global sea level rise “saved” would be 2.6 cm, or one inch. A complete cessation of CO2 emissions in South Carolina is only a tiny fraction of the worldwide reductions assumed in Dr. Wigley’s global analysis, so its impact on future trends in global temperature and sea level will be only a minuscule fraction of the negligible effects calculated by Dr. Wigley.
We now apply Dr. Wigley’s results to CO2 emissions in South Carolina, assuming that the ratio of U.S. CO2 emissions to those of the developed countries which have agreed to limits under the Kyoto Protocol remains constant at 39% (25% of global emissions) throughout the 21st century. We also assume that developing countries such as China and India continue to emit at an increasing rate. Consequently, the annual proportion of global CO2 emissions from human activity that is contributed by human activity in the United States will decline. Finally, we assume that the proportion of total U.S. CO2 emissions in South Carolina – now 1.4% – remains constant throughout the 21st century. With these assumptions, we generate the following table derived from Wigley’s (1998) mid-range emissions scenario (which itself is based upon the IPCC’s scenario “IS92a”):
Projected annual CO2 emissions (mmtCO2)
Note: Developed countries’ emissions, according to Wigley’s assumptions, do not change between 2025 and 2050: neither does total U.S or South Carolina emissions.
In Table 2, we compare the total CO2 emissions saving that would result if South Carolina’s CO2 emissions were completely halted by 2025 with the emissions savings assumed by Wigley (1998) if all nations met their Kyoto commitments by 2010, and then held their emissions constant throughout the rest of the century. This scenario is “Kyoto Const.”
Projected annual CO2 emissions savings (mmtCO2)
Table 3 shows the proportion of the total emissions reductions in Wigley’s (1998) case that would be contributed by a complete halt of all South Carolina’s CO2 emissions (calculated as column 2 in Table 2 divided by column 3 in Table 2).
South Carolina’s percentage of emissions savings
Using the percentages in Table 3, and assuming that temperature change scales in proportion to CO2 emissions, we calculate the global temperature savings that will result from the complete cessation of anthropogenic CO2 emissions in South Carolina:
Projected global temperature savings (ºC)
Accordingly, a cessation of all of South Carolina’s CO2 emissions would result in a climatically-irrelevant global temperature reduction by the year 2100 of no more than two thousandths of a degree Celsius. Results for sea-level rise are also negligible:
Projected global sea-level rise savings (cm)
A complete cessation of all anthropogenic emissions from South Carolina will result in a global sea-level rise savings by the year 2100 of an estimated 0.04 cm, or less than two hundredths of an inch. Again, this value is climatically irrelevant.
Even if the entire United States were to close down its economy completely and revert to the Stone Age, without even the ability to light fires, the growth in emissions from China and India would replace our entire emissions in little more than a decade. In this context, any cuts in emissions from South Carolina would be extravagantly pointless.
The observations we have detailed in this report illustrate that climate variability from year-to-year and decade-to-decade plays a greater role in South Carolina’s climate than any long-term trends. Such short-term variability will continue dominate South Carolina’s climate into the future. At the century timescale, South Carolina’s climate shows no statically significant trend in statewide average annual temperature, statewide total annual precipitation, or in the frequency and/or severity of droughts—an indication that “global warming” is anything but “global” and also strong evidence that local and regional processes are more important than global ones in determining local climate and local climate variations and changes. The same is true for tropical cyclones impacting South Carolina and the United States—there is a great degree of annual and decadal variability that can be traced long into the past, but no 20th century trends in frequency, intensity, or damage. Global sea levels are indeed rising, but they are rising, and should continue to rise, at a pace that is not dissimilar to the pace of rise experienced and adapted to during the 20th century. And climate change is shown to have little, if any, detectable impacts on the overall health of South Carolina’s population. Instead, application of direct measures aimed at combating the negative impacts of heat waves and vector-borne diseases prove far and away to be the most efficient and effective methods at improving the public health.
Further, no emissions reductions by South Carolina will have any detectable regional or global effect whatsoever on climate change.
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