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Climate History and Climate Changes in Georgia

Summary for Policy Makers

The observations we have detailed herein illustrate that climate variability from year-to-year and decade-to-decade plays a greater role in Georgia’s climate than any long-term trends. Such short-term variability will continue dominating Georgia’s climate into the future.

At the century timescale, Georgia’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. In stead, observations show that the first part of the 20th century was warmer than the latter half — an indication that “global warming” is anything but “global” and also provides 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 Georgia 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 rising at a pace that is not dissimilar to that 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 Georgia’s population. 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."

I. Observed Climate

A. Temperature

An examination of Georgia’s statewide temperature history within the four seasons, shows no evidence of any “global warming” throughout any portion of the year. Recent temperatures are unremarkable in every way and no long-term warming trends are present. In fact, within every season, the temperature trend from 1895-2006 is negative, indicating a general cooling tendency.

B. Precipitation

C. Drought

According to the Dr. David Stooksbury, the Georgia State Climatologist, drought is a normal part of Georgia’s climate. In a recent article titled “Historical Droughts In Georgia And Drought Assessment And Management” Dr. Stooksbury wrote:

Drought is a normal component of the Southeastern US climate system. Many of Georgia’s native ecosystems depend on drought for health and survival. While drought is a natural component of the climate system, its negative impacts on the state’s environmental, economic, and social systems can be major. The droughts of the 1920s accelerated the mass migration of poor farmers from rural Georgia. Many rural counties reached their peak population in 1920 and have remained below the 1920 level since then.

The period from the middle 1950s through the middle 1990s was relatively benign in climate history. During this period droughts were relatively infrequent and of short duration. However, the 1998-2002 drought was more in line with past Georgia climate patterns. Since the 1998-2002 drought is more indicative of the climate record than the 1956-1997 period, planners need to use long-term records for proper planning.

In other words, recent drought conditions appear unusual only when consulting a short record. For instance, on the whole, the past several decades prior to 1998 were relatively drought free in Georgia. Examining a longer term record, however, shows that extended drought conditions are not unusual, and places recent drought conditions in their proper climate context. Thus, there is no evidence of any recent behavior that is out of the ordinary within the long-term perspective.

This fact can be further evidenced by examining an even longer-term record of moisture conditions in Georgia. Using information contained in tree rings, Dr. Edward Cook and colleagues were able to reconstruct a summertime PDSI record for central Georgia that extends back in time more than 1500 years. That paleoclimate record of moisture indicates that alternating multi-decadal periods of wet and dry conditions have occurred with regularity during the past 1500 years, emphasizing the point made by the Georgia State Climatologist, that droughts are a normal part of the region’s climate system.

II. Sea Level Rise

The relative sea level along the Georgia coast has changed due to a combination of the land slightly sinking and the ocean slightly rising (Aubrey and Emery, 1991; Wöpplemann et al., 2007). Georgia’s coastal residents have successfully adapted to this change, as the unprecedented high (and growing) population of coastal Georgia attests. From 1970 to 2000, the population of Georgia’s 10 coastal counties grew by 62%, increasing from 342,750 residents to 558,350. Projections for the coming decades, produced by the Center for Quality Growth and Regional Development at the Georgia Institute of Technology, project that the coastal population will increase by another 51% reaching a total of 844,161 people by the year 2030.

According to the 2007 Fourth Assessment Report (AR4) on climate change published by the U.N.’s Intergovernmental Panel on Climate Change (IPCC), the potential sea level rise over the course of the 21st century lies between 7 and 23 inches, depending of the total amount of global 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 of 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 from the rate of sea level rise that Georgia’s coastlines have adapted to for more than a century.

There are a few eccentric individuals who argue that sea level rise will accelerate precipitously in the future and raise the level of world oceans to such a degree that they inundates low-lying areas along the Georgia coast and other low-lying areas around the world, clamoring that the IPCC was far too conservative in its projections. However, these rather alarmist views are not based upon the most reliable scientific information, ignoring what our best understanding of how a warmer world might impact ice loss/gain on Greenland and Antarctica and correspondingly, global sea level. 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), acting to slow the rate of global sea level rise (because the water remains trapped in ice and snow). 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 a likelihood of zero.

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:

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.

III. Hurricanes

Thanks largely to its geographic positioning; Georgia’s coastline is among the least likely places for hurricanes to make landfall along the U.S. coast from Brownsville, Texas to the Chesapeake Bay. Data from the National Hurricane Center indicates that the average time between hurricane passages (hurricanes passing within 86 miles of the coast) ranges from about 11 years at the southern portion of coastal Georgia to about 14 years along its northern part. The average time between direct hurricane landfalls is even less. Consider that in the 107 years between 1900 and 2006, only 4 hurricanes made landfall in Georgia (the last being Hurricane David in 1979).

But this is not to say that Georgia is immune from the impacts of hurricanes and tropical storms. Quite the contrary. Between 1881 and 1898 three strong hurricanes made landfall in Georgia and two of them rank among the top-10 deadliest hurricanes in U.S. history. On August 27, 1881 a strong category 2 storm made landfall just south of Savannah, at Ossabaw Island, and killed between 300 and 700 people and on August 27-28, 1893, a category 3 storm made landfall just south of Tybee Island, directly to the east of Savannah and killed up to 2,500 people along the Georgia and South Carolina coasts, ranking it as the 5th deadliest hurricane ever to strike the United States. And even if the state is not subject to a direct hurricane landfall, tropical cyclones can wreak havoc. For instance, in 1994 tropical storm Alberto came ashore along the Florida panhandle, but stalled in its passage over Georgia, dumping 27.61 inches of rain on the town of Americus (21.10 inches of which fell in a 24-hr period setting the state’s all-time 24-hr rainfall record). The flooding that resulted from the widespread torrential rains resulted in 33 deaths and $500 million in damages. Just over a year later, the remnants of Hurricane Opal traversed the state and the associated high winds, heavy rains, and tornadoes killed 14 people and 50 counties were declared major disaster areas.

Thus, despite its rather sheltered shoreline, Georgia is still quite susceptible to devastating impacts from tropical storms and hurricanes. Therefore, any changes in the frequency, intensity, or preferred tracks of Atlantic tropical cyclones may be of particular interest to Georgia’s coastal and inland residents, alike.

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 natural, long-term cycles, and that this latest upswing is simply a return to conditions that characterized earlier decades in the 20th century.

One recent research group has gone even further, and provides evidence that cycles of hurricanes impacting Georgia can be traced back several centuries. Dana Miller and colleagues recently published a paper in the Proceedings of the National Academy of Sciences in which they describe their research efforts in using chemical tracers stored in tree rings collected near Valsota, Georgia to determine when hurricanes passed nearby. The authors explain how the isotopic make-up of tropical cyclone precipitation differs from that of other types of precipitation that falls at Valdosta. This chemical marker of the precipitation is stored in the annual growth rings of longleaf pine trees growing in the region and careful analysis of the chemical make-up of the wood within each ring provides an indication as to whether tropical cyclone precipitation fell that year in the study location. Using this technique applied to tree rings records extending back to the late 18th century, the researchers find indications of tropical cyclone passages that tend to occur in clumps, indicating alternations between active and inactive periods.

Miller’s team writes that the proxy record “shows close agreement with instrumental records that the 1950 decade was the busiest for hurricane activity in the 20th century. The proxy record further supports historical records that suggest significant tropical cyclone activity for the southeastern United States between 1865–1880. The isotope proxy detects six storms in the 1870 decade, although only one (1871; the largest 1870 decade anomaly) appears to have made direct landfall on the Georgia coast. Other decades of apparent activity include the 1840 and 1850 decades, 1800–1820 decades, and 1770s decade. Periods of relative quiescence in Georgia appear to be the 1781–1805 (except 1793 and 1795) and the 1970 decade.” They go on to describe ‘‘Great Hurricanes’’ of 1780, 1847, and 1857.

Furthermore, they note that “Over the period 1855–1940, the isotope proxy indicates 22 years with tropical cyclones, 21 of which are reported in the historical record to have affected the general study area. For the period 1770–1855, the proxy suggests many more years (25 years) affected by one (or more) tropical cyclones.” There were 2.9 storms per decade from 1770-1885 but only 2.5 storms per decade from 1855-1940.

There are many lessons from this tropical cyclone reconstruction. First, it is obvious that large hurricanes have impacted southern Georgia throughout the past 220 years, and some of the storms were larger than any storm in recent years. But more importantly, the record shows that some periods are active, others are quiet, and that this has been the case for a long time into the past (i.e. prior to any large-scale anthropogenic climate influences). This means that there is now more reason to believe that variations during the 20th century in the frequency and intensity of Atlantic tropical cyclones are very likely to have a significant natural component to them.

And based upon the statistics from natural variations alone, Georgia is long overdue for a direct strike from a major hurricane as it is been more than a century since the last one directly struck the state. And when the next major hurricane does hit Georgia, it will encounter a state whose population demographics, as evidenced by the large influx of people to the state’s coastal counties, have changed enormously since the last major storm impact. A direct strike from a major hurricane (or any hurricane for that matter) will likely lead to significantly 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.

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.

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 Georgia or the U.S. coast, or damage to U.S. coastlines when population demographics are taken into account, the impact from a single storm can be enormous as residents of Georgia 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 Georgia are not negative. In fact, precipitation that originates from tropical systems and that eventually falls over the state of Georgia proves often to be quite beneficial to the state’s 8 billion dollar/year 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 Georgia, on average, receives almost 20 percent of its normal September precipitation, and about 9 to12 percent of its total June through November precipitation from passing tropical systems. And since about three-quarters of Georgia’s field crops such as corn, wheat, 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.

IV. Public Health Impacts

A. Temperature-related Mortality

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 below 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 in many cities in the southeastern United States, there is no bar at all in the 1990s, indicating that there were no statistically distinguishable heat-related deaths during that decade (the most recent one studied). In other words, the population of those cities has become nearly completely adapted to heat waves.

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. A notable exception to this pattern of declining sensitivity to heat waves is found in Atlanta, Georgia. In Atlanta, there seems to have been little difference in the mortality rate from extreme heat events from the 1960s to the 1990s.

The actual reason behind this anomalous behavior is presently unclear. However, it most likely represents some rather unique situation that is local to the city of Atlanta. As other surrounding cities all have become better adapted to the occurrence of high temperature events, even in light of the rising temperature which accompany landscape changes associated with urban and suburban growth. Atlanta’s lack of adaptation perhaps suggests that more proactive measures need to be developed in the Atlanta metropolitan area—improved watch/warning systems, more available cooling centers, etc.—to make the public better aware of the threats that can accompany heat waves. As the period of record in the Davis et al. (2003b) study ended in 1998, it is possible that in the intervening years, Atlanta has improved its measures to respond to high temperature events, if not, perhaps this situation presents an opportunity for steps that can readily be taken to improve the city’s response to heat waves, to better prepare themselves not only for any future climate warming, but simply for the extremes of summertime temperatures that are natural to the climate of Georgia.

In general, the overall pattern of the distribution of heat-related mortality shows in cities across the United States indicates 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.

In a subsequent study, Davis et al. (2004) focused not just on summertime heat/mortality relationships, but looked across all months of the year. Davis et al. (2004) found that, in Atlanta, like in most cities across the United States, higher temperatures in the months of July and August were often associated with increased mortality, but that in the most other months, the association ran in the opposite direction, that is, cooler temperatures were associated with mortality increases.

The figure above (taken from Davis et al., 2004) illustrates this pattern of temperature/mortality relationships for Atlanta. Negative bars indicate a negative relationship between temperature and mortality, that is, the colder it is, the more people die and vice versa for warmer than average conditions (i.e., the warmer it is, the fewer people die). Solid bars mean the relationship is statistically significant. Positive bar indicate positive relationships between temperature and mortality, that is more people die when it is hotter than normal, and few die when it is below normal. For the most part, Atlanta exhibits more negative bars than positive ones, with the cold season months showing negative relationships and a couple months in summer showing weak positive relationships. Taken together, this indicates that if the future was marked by a warming climate, especially one in which winters warmed a greater degree than summers (in character, matching the pattern of warming that has been observed in the Northern Hemisphere for the past 50 years or so), that this would result in fewer temperature-related deaths in Atlanta and probably throughout Georgia.

All told, however, the total annual number of direct weather-related deaths, whether as a result of cold or warm conditions, is quite small compared to the annual overall mortality. For instance, in general, in the United States, the annual mortality rate is a bit less than 1% per year, meaning that about 8,000 to 9,000 people die each year out of every million persons. In Atlanta, the net effect of the weather in a typical year is about 1,000 times less, or fewer than ±10 deaths per million people. So, despite proclamations to the contrary, the weather and climate have only an exceedingly small impact on overall mortality when the population at large is considered. This is true now and will remain true into the future, no matter how the climate evolves.

B. “Tropical” Disease

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.

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 stretching from the Gulf Coast all the way up into Northern Minnesota—including the southern half of Georgia. 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. The CDC was located in Atlanta, Georgia primarily because this region was the primary one which was still affected by the disease. 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 Unites States, but the transmission cycle has been disrupted and the pathogen leading to the disease is absent. Climate change is not involved.

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).

Impacts of climate-mitigation measures in Georgia

Globally, in 2003, humankind emitted 25,780 million metric tons of carbon dioxide (mmtCO2: EIA, 2007a), of which Georgia accounted for 168 mmtCO2, or only 0.65% (EIA, 2007b). This proportion of manmade CO2 emissions from Georgia will decrease over the 21st century as the rapid demand for power in developing countries such as China and India outpaces the growth of Georgia’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 5 times greater than Georgia’s total emissions. Even a complete cessation of all CO2 emissions in Georgia will be undetectable globally. A fortiori, regulations prescribing a reduction, rather than a complete cessation, of Georgia’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 Georgia – a worse than stone-age existence – would represent only a tiny fraction of the worldwide reductions assumed in Dr. Wigley’s global analysis, so the reductions impact on future trends in global temperature and sea level would be only a minuscule fraction of the negligible effects calculated by Dr. Wigley.

We now apply Dr. Wigley’s results to CO2 emissions in Georgia, 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 contributed by human activity in the United States will decline. Finally, we assume that the proportion of total U.S. CO2 emissions in Georgia – now 2.9% – 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”):

In Table 2, we compare the total CO2 emissions saving that would result if Georgia’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.”

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 Georgia’s CO2 emissions (calculated as column 2 in Table 2 divided by column 3 in Table 2).

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 Georgia:

Accordingly, a cessation of all of Georgia’s CO2 emissions would result in a climatically-irrelevant global temperature reduction by the year 2100 of no more than five thousandths of a degree Celsius. Results for sea-level rise are also negligible:

A complete cessation of all anthropogenic emissions from Georgia will result in a global sea-level rise savings by the year 2100 of an estimated 0.08 cm, or about three 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 Georgia would be extravagantly pointless.

V. Additional Reading

Kentucky Climate Profile http://scienceandpublicpolicy.org/originals/kentucky_climate_profile.html

Hurricane Threat to Florida: Climate Change or Demographics?

http://scienceandpublicpolicy.org/originals/hurricanethreat.html