By Van Smith
First published in City Paper, Nov. 20, 1996
“Everybody talks about the weather, but nobody does anything about it.” The stock of that famously pat phrase, often attributed to Mark Twain, has been dropping of late. As about 300 scientists from the world over agreed last year during a United Nations conference on world climate in Rome, “The balance of evidence suggests a discernible human influence on global climate.”
According to worldwide measurements, that climate is changing. In terms of temperature, the group concluded, the Earth is heating up faster than it has at any time in the past 10,000 years. Twain be damned, we are doing something about the weather, whether we mean to or not.
The scientists’ statement, made in a report issued but the Intergovernmental Panel on Climate Change (IPCC), suggest we are suffering from an inadvertent form of hubris: By existing in ever larger and technologically advancing numbers (as humans are wont to do), we may be setting in motion our own demise. The distant past tells us that a significantly changing climate causes great transformations in life on Earth. In the modern world, with its unprecedented population growth and rapidly developing, large-scale patterns of human settlement, great social upheaval is likely to follow any critical changes in global climate. Indeed, minor climate fluctuations in the past have coincided with periods of social and political upheaval. If some of the current predictions of global climate change – shaky though they are – prove correct, the world will become a very uncomfortable place indeed.
In May, the World Meteorological Organization (WMO) issued its annual “Statement on the Status of Global Climate,” revealing that 1995 was the hottest year since reliable worldwide temperature recording began in 1861. WMO’s findings buttress the scientific consensus of the 1995 IPCC report, which concludes that over the last 100 years the mean global temperature over land increased by nearly one degree Fahrenheit, over sea by nearly 1.3 degrees, and in the deep ocean by nearly two degrees; that sea level has risen by between one and two centimeters per decade; and that carbon dioxide in the atmosphere has increased nearly 30 percent. Nine of the 10 warmest years in the 100-year period have occurred in the past decade, the group found.
The IPCC, the 300 or so delegates of which represent the collective wisdom of 2,500 climate experts, also made projections about future global climate change. By 2100, the group predicts, the mean global temperature will rise been 1.8 and 6.3 degrees Fahrenheit, and the sea level will rise between six and 37.5 inches; the panel’s “best estimate” is a 3.6-degree warming and a nearly 20-inch rise in sea level. It also predicts more storms and droughts, both of greater intensity. These and other climatic changes, the panel says, will have a grave impact on agriculture and forestry, ecosystems, water resources, human settlements, energy, transportation, industry, human health, and air quality, among other things. The IPCC’s projections present an alarmingly bleak picture of a fast-changing future environment.
Given the potential hazards of climate change, Marylanders would be well-advised to start thinking about the possible consequences for the Free State’s people, economy, and ecosystems. But there’s a problem here. Reducing the predicted global phenomenon to the regional level, then reducing it further to the state level, is a complicated matter.
Unless there’s a bevy of researchers we weren’t able to locate, it appears that Maryland’s scientific brain trust has achieved little in nailing down the specific implications of climate change for Maryland, although some promising work is underway. Instead, scientists studying Maryland’s climate have been concentrating on pinning down the truth about what’s already occurring: climate change tied to urbanization and a rise in the level of the Chesapeake Bay.
But, as Bob Dylan sang, “You don’t need a weatherman to know which way the wind blows.” A review of Maryland’s recent weather extremes and odd meteorological events makes the casual weather watcher wonder: Are the global changes currently causing any local change? And if so or even if they aren’t – what should we in Maryland do about the prospects of climate change?
The theory of global climate change rests on the “greenhouse effect,” a known phenomenon in which atmospheric gases – primarily carbon dioxide, methane, and water vapor – trap heat from the sun and keep it near the Earth’s surface. The service these gases perform is essential to life; they keep the Earth more than 60 degrees warmer than it would be without them.
The question is, what happens when the atmospheric concentration of greenhouse gases rises? Research by paleoclimatologist, who study ancient weather patterns, indicates that in the planet’s distant past, temperatures rose as greenhouse gas concentrations increased. Since human activities are causing rapid increases in all greenhouse gases, there is good reason to be concerned about the possibility of human-caused climate change.
Knowledge of the human influence on global climate has been building during the entire century-and-a-half history of modern industrial development. The greenhouse effect was first proposed and studied by European scientists in the mid-19th century. In the late 1800s scientists first theorized that industrial processes, by burning carbon-based fossil fuels, are probably increasing carbon dioxide concentrations in the atmosphere. Then, at the turn of the century, Svante Arrhenius, a Swedish chemist, calculated how much temperatures were expected to increase as carbon dioxide increases. By 1900, most of the pieces of the carbon dioxide/climate puzzle were already in place.
“Nevertheless,” William Kellogg of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, wrote in a 1987 article in the scientific journal Climatic Change, “the intriguing idea that mankind could raise the earth’s temperature seems at first to have attracted surprisingly little attention in the scientific community and even less in the public media.” It was not until 1957, when two scientists at the Scripps Institution of Oceanography wrote an article proclaiming, “Human beings are now carrying out a large-scale geophysical experiment” by testing the greenhouse effect, that science and the public began to wise up to the potential for climate change. In 1965 the U.S. government for the first time publicly recognized the human contribution to the greenhouse effect.
Public concern picked up rapidly after a series of climate-related disasters took a tragic toll on human life and world food supplies. Crop failures in the Soviet Union and India, severe drought in Africa, fishery collapses in South America, poor U.S. corn production, and major droughts in the United States and Europe all occurred in the space of four years, causing widespread famine and agricultural losses estimated in the billions of dollars.
Ironically, much of the resulting anxiety focused on one climatologist’s theory that the disruptions were due to the advent of a new little ice age, as evidenced by a 30-year cooling in Northern Hemisphere temperatures and supported by the assertion that, according to our knowledge of past climates (gained by the efforts of paleoclimatologists) the time is ripe for another glacial period. The theory included predictions of many of the same damaging changes as would be caused by global warming, including more extreme climate, periodic droughts, and monsoon failures reducing rice production in Asia.
The prospect of an increasingly variable climate caused great concern about potential food shortages. NCAR’s Stephen Schneider, a major figure in the last 20 years of climate research, proposed in the mid-1970s what he termed the Genesis Strategy, which called for maintaining food stockpiles to guard against famine, just as Joseph did the Book of Genesis in the Bible. Schneider’s proposal, though not implemented, was timely: Due to the early-1970s climate disasters, shortage in U.S. grain reserves developed in the mid-1970s, creating concern that radical climate change could cause a catastrophic food scarcity the world over.
To help focus climate research, the U.S. Senate in 1976 convened a six-day hearing on whether to establish a national climate program. The program never materialized, but the hearing report reads like any number of today’s policy papers on the issue: “Because of the long lead times involved in reversing established technological and economic patterns, and because of the seeming irreversibility of such phenomena as the carbon dioxide effect, it is not permissible to allow the earth to perform [an] experiment in hopes of obtaining better data. Policies are needed to make decisions now based on uncertain and probabilistic information.”
The same message was heard in Congressional hearings in 1988, when the Mississippi River all but dried up during an extreme summer drought, causing widespread public alarm about global warming. It was heard again in 1990, when IPCC issued its first report, summarizing the state of our climate knowledge and made dire predictions about future climate change. And it was heard again last year, when that international panel issued a new climate report, this time saying humans are partially responsible for the climate changes already detected.
Nonetheless, a deep-seated skepticism remains among scientists and the public about the alarms. And with good reason – projecting global climate change is an inexact process involving technology that has been questioned. Temperature readings are taken from thermometers distributed primarily in urban areas, which are known to be warmer – indeed, much warmer – than rural areas; corrections for this are made in calculating the averages, but the problem introduces an element of doubt about the resulting numbers. The accuracy of tidal gauges used to record sea level is questioned; again, corrections are made, and again, such adjustments raise accuracy concerns. Finally, predictions of future climate are developed by numerous computer-based global-climate models that are the subject of intensely heated debate among scientists, who admittedly have only an elemental understanding of the climate system’s dynamics.
If nothing else, though, one thing is clear about climate-change theory: Its basic elements have been known to science for 150 years, and its general implications have been understood and explained consistently for two generations. Many, many uncertainties remain – particularly regarding the role of oceans and clouds in the global climate system – and new questions are sure to arise as new knowledge is gained. But continued climate research, rather than weakening the overall theory, has served to confirm it, at least on a global scale.
One key aspect of climate change that remains largely out of focus is how it would be expressed regionally. In certain “hot spots” – sub-Saharan Africa, the lowlands of India, tropical rain forests, and the polar ice caps among them – researchers have been trying in earnest to understand what potential disasters lurk in the climate-change projections. But climatologically, smaller areas such as Maryland and the Chesapeake Bay are largely uncharted territory.
Not that there isn’t some official awareness of the threat in Maryland. In mid-October, Sarah Taylor-Rogers, assistant secretary of the Maryland Department of Natural Resources, addressed the problem directly before an Eastern Shore audience made up largely of farmers, fishermen, and property owners. According to a transcript of the speech appearing in the newsletter of the conference sponsor, the Climate Institute of Washington, D.C., Taylor-Rogers pointed out that the projected rise in Maryland’s population (between 1990 and 2020 an additional 1.3 million residents are expected, a 28 percent increase) “is significant because it is this very growth and development occurring all over the world that has primarily been attributed as accelerating climatological changes, evidenced by sea-level rise in the bay as well as intensified and more numerous storm occurrences” in the region.
At the same conference, dubbed “Chesapeake Bay at the Crossroads,” Stephen Leatherman of the University of Maryland Laboratory for Coastal Research explained the scientific understanding of sea-level rise in the Chesapeake Bay. Much of what he said is spelled out more comprehensively in Vanishing Lands: Sea Level, Society and the Chesapeake Bay, a 1995 publication that Leatherman coauthored.
“There is much we do not know about the response of the Bay ecosystem to sea-level rise,” Leatherman admits in Vanishing Lands, adding, “We do know that the seas are rising … at least three times faster during the last century than during the last 5,000 years.” A two-to-three-foot rise over the next 100 years, as is predicted, would pose “immediate consequences for low-lying coastal lands” such as on the Eastern Shore, he writes.
James Titus of the U.S. Environmental Protection Agency (EPA) has projected specific figures for sea-level rise in Maryland. Over the next 100 years, he predicts a two-foot rise, 60 to 70 percent of which will be due to climate change.
Court Stevenson, a plant ecologist with the University of Maryland Center for Environmental and Estuarine Studies, says the bay’s waters are rising between two and five millimeters per year – faster than the global rate of sea-level rise of one to two millimeters per year. The consensus, he says, is that the rate of the rise in the bay’s waters started increasing around 1850. One indication of the rise, he points out, is that some of Baltimore City’s “early land grants are now under water.”
On the Eastern Shore, Stevenson says, “the largest single island in Maryland” has been created over the last 50 years in Dorchester County due to a combination of rising seas and subsiding land, dividing the county with tidal water. Another dramatic sea-level-related change has been in the Blackwater Wildlife Refuge, at least one-third of which has become submerged by bay water since the 1930s.
Given the existing effects of the bay’s rise, Stevenson says he is “astounded” and “deeply concerned” by the implications of predicted future increases. “If we see anything like two feet, we’ve got such flat land here [on the Eastern Shore], we’re going to see a lot of changes,” he says. “It is going to be significant in terms of the economy of the region.” Farmland, woods, and marshes, he says, will be lost from inundation or salt intrusion from the bay’s brackish waters. If a major storm barrels up the bay, Stevenson points out, “We’ll probably lose a lot of things very rapidly … The impact is looking tremendous, and I don’t think anyone has really calculated the impacts.”
One of the concerns about sea-level rise in the bay is whether it will wreak havoc with our energy systems. But Baltimore Gas and Electric (BGE), the region’s power supplier, is not currently concerned. “It is not something we have looked at,” BGE spokesperson Art Slusark says of the potential impacts of sea-level rise on its system, “nor has it been something that has been a factor” in planning for the utility’s future. Slusark says the company believes the bay’s rise will take so long that “our existing plants will be out of service before it happens.”
On the Western Shore, much of which is bordered by cliffs, there is “a lot of concern” that sea-level rise will cause dramatic shore erosion and “cliff retreat,” Stevenson says. “A lot of development is pretty close to the cliff – it is a big problem.” The only technology to prevent buildings from toppling over is the use of bulkheads along the shoreline to prevent wave action against the base of the cliffs. “The cheapest wooden bulkheads coast about $300 to $400 per linear foot, and there are many miles that would need protection,” Stevenson estimates. He calls cliff retreat “a time bomb waiting to happen.”
(Calvert Cliffs, where BGE’s nuclear reactors are located, is being significantly affected by cliff retreat, Stevenson says, but the nuclear facility is set back far enough from the cliffs to allay any immediate concern.)
Despite the potential for a dramatic rise of the bay, EPA’s Titus says public policy in Maryland does not yet officially recognize that it is happening (although officials are aware of the problem). For example, the state Critical Areas Act, designed to restrict shoreline development and preserve the bay’s coastal ecosystems, has been effective, but less and less land will be protected as the water continues to rise and shoreline is eaten away.
Meanwhile, Titus says, landowners try to prevent erosion of their waterfront property by installing bulkheads – a measure that as a practical matter denies the traditional right of public access to the shoreline up to the high-tide line. As the sea level rises and erosion occurs, he explains, the bay’s waters will lap up against the bulkheads, effectively privatizing the shoreline on which many rely for either income or recreation. He says 20 miles per year of the bay’s shoreline is already being lost to erosion, with the gravest losses on islands, some of which are inhabited and losing acreage quickly.
Titus says that state officials are planning to shore up inhabited islands with dredging spoils dug up to maintain shipping channels; the spoils currently are disposed of on the uninhabited Poplar Island. “It would be relatively expensive to ship spoils to these islands, but if we consider it worthwhile to spend hundreds of millions to have a football team, we may feel it worthwhile to preserve these islands, some of which have had people living on them for hundreds of years.
“Our policies depend on the assumption that the seas are not rising and the shoreline is not eroding,” Titus says. “But the science, on the other hand, says that sea-level rise is already happening and [there is] a high expectation that it will continue.”
Despite the upward trend in global temperatures, no warming has been observed in the northeast United States, Titus says. The generally accepted explanation for this, he says, is “the sulfate cloud that hangs over the entire region.” The cloud is a result of industrial pollution and is made up of hydrogen-sulfate ions, which are highly reflective and cause solar radiation to bounce back up into the atmosphere rather than reach the planet’s surface. This masks the regional influence of the global-warming trend. (It also exacerbates urban pollution, Titus and others point out, because increased radiation encourages smog formation from sulfates, and smog has serious health effects.)
Nonetheless, on the local level – and, some say, even on the regional level – significant warming has been detected, but it is attributed to another phenomenon: the “urban heat-island effect.” In essence, this occurs wherever population is increasing and changes in land use are intensifying. More people means more industry, more automobiles, and other things that generate heat. It also means more buildings and roads and less vegetation; as a result, heat is retained by building materials during the day and is given off slowly at night, offsetting what would otherwise be cooling temperatures. Thus urban areas record higher temperatures than rural areas. Other climatic impacts from the urban heat island, experts say, include more precipitation, less snowfall, and more unstable air, which promotes tornadoes.
A clear demonstration of Baltimore’s urban heat island has been found by Helmut Landsberg of the University of Maryland Institute for Fluid Dynamics. Landsberg compared temperatures in the city with those of Woodstock, a rural town about 15 miles away, between 1904 and 1979, a period during which the metropolitan area’s population grew from about a half-million to two million. Woodstock’s annual mean temperatures remained unchanged, but Baltimore’s rose about 3.5 degrees – a very stark difference.
Arthur Viterito, a George Washington University geography professor who is one of the primary researchers of the urban-heat-island effect in this area, believes the Baltimore region’s heat island is pronounced and spreading – to the point of merging with other nearby heat islands. In a 1989 paper published in Climatic Change, Viterito demonstrated how Baltimore’s heat island combined with Washington, D.C.’s between 1950 and 1979, creating a continuous “heat corridor” along the axis between the two cities. Overall, he found, the Baltimore-Washington corridor has become three degrees warmer since 1950.
“Warming has continued in the Baltimore-Washington corridor,” Viterito says, and he asserts that it is spreading as rural expanses become developed all around the area, including along the main routes to Annapolis. As far as he knows. “No one has really looked at the merging of heat islands for different cities” outside of this area, but Viterito believes the phenomenon is spreading to other parts of the Eastern seaboard as well.
“You really do get permanent climate change on a regional scale now – not just local,” he says. “Within the next 50 years, we are going to see large-scale change [from merging heat islands] in the Boston-Richmond corridor … . A large part of global climate change is attributable to urban growth.”
Other than demonstrations of the urban heat island, not much has been done to analyze Maryland’s climate to determine if it is changing. Viterito says he has “not seen anything done on the local climate since 1989,” when his paper came out. This leaves a big question mark, and an unfortunate one, because it appears from the available data on Maryland’s climate that extreme events are occurring more regularly.
For instance, tornadoes have been touching down more regularly in the Baltimore area – one hit North Avenue in November 1994.
Another troubling trend – one that is causing extensive damage to the Chesapeake Bay’s ecology, scientists say – is the near-record-high levels of fresh water running of into the bay in recent years. So far, 1996 has had the second-highest average daily flow on record, and 1993 and 1994 were significantly above-average years as well, according to figures maintained by the U.S. Geological Survey.
Such anomalies, as well as record monthly and annual temperature and precipitation averages, make lay people wonder what’s up with the weather. Answers aren’t forthcoming.
For instance, state climatologist Alan Robock, who is also a meteorology professor at University of Maryland, does not have a prepared study available for the public about Maryland’s climate.
“I don’t have all these records at my fingertips,” he explains. When asked if Maryland’s climate is thought to be growing more variable, what with reputed global climate change and the urban heat island effect, he responds, “It is normal for the weather to be variable and it is normal for the climate to change.”
On the Internet, monthly climate reports are available from the Northeast Regional Climate Center at Cornell University in Ithaca, New York. Records of extreme mean temperatures and extreme precipitation amounts include some interesting facts about Maryland’s recent climate: In 100 years of record-keeping, 16 records have been set for Maryland since 1981. 1990 was the hottest year on record. The summer of 1987 was the hottest summer on record, and record mean highs for four months – April, May, November, and December – were set during the period of 1984 to 1994. The only record for cold set recently was the 24.5-degree mean temperature in December 1989.
Regarding precipitation, four of the driest months and three of the wettest months in Maryland in the last 100 years occurred between 1983 and 1994. The driest spring occurred in 1986, with only 5.52 inches of precipitation; the wettest came in 1983, with 19.06 inches.
In the past two years alone, Maryland has had 17 monthly or seasonal temperature averages for precipitation readings that fall within the top 10 for those categories in 100 years of record-keeping.
Meanwhile, at Baltimore-Washington International Airport, where records have been kept since 1950, the record peak wind gusts for each of the 12 months of the year were recorded between 1985 and 1995. 1990 was the warmest year on record at BWI, 1991 was the second-warmest, and the next five warmest years occurred in the 1980s.
These climatic highs and lows occurring in recent clusters seem odd, but, as Robock explained, weather is always variable and climate is always changing. Without serious analysis, little can be made of these numbers other than that they are interesting and seem to indicate a lot of weather swings in recent years.
They are even more provocative because the records are occurring in conjunction with other extreme weather events, such as the all-time record snowfall total for 1996; the extended drought in 1995 that threatened Baltimore water supplies; large and growing numbers of reported tornadoes outside of the normal tornado season; and severe storms that dump extremely heavy rain in short periods of time. Most of these occurrences are anecdotal and might fall within the normal bounds of weather variability, but no scientist we contacted has studied or is aware of any studies showing whether they do or not.
One of the more worrisome aspects of global climate change, one with possible consequences for this area, was studied recently by Jonathan Patz, a virologist at the Johns Hopkins University School of Hygiene and Public Health. The resulting article, published in the Journal of the American Medical Association in January, raises concerns that global climate change “can affect the introduction and dissemination of many serious infectious diseases.”
In particular, Patz and his coauthors note that climate-sensitive mosquito-borne diseases (e.g., malaria and dengue fever) and waterborne infections and toxin-related illnesses (e.g., cholera and shellfish poisoning) may become more widespread in a warmer climate, especially if human populations become more susceptible due to other climate-related impacts.
Patz summarized his research in a November 13th presentation at the Hopkins School of Hygiene and Public Health. He pointed out that worldwide, 11 climate-related disease outbreaks have already occurred in the 1990s.
Mosquito-borne diseases, he says, are likely to cause epidemics in warmer climates because the insects tend to be smaller and therefore need to bite more times in order to reproduce. Each bite increases the likelihood of disease transmission. This change may cause widespread fatal sickness, particularly in conjunction with other factors, such as the spread of the disease-carrying mosquitos into populations that have not developed immunity to the diseases. Also, such parasites have faster incubation periods in higher temperatures, which is “very important in terms of epidemic spread,” Patz said.
Patz is continuing his research into the disease-related impacts of global climate change and is starting to look into the potential of such problems – possibly even the spread of traditionally subtropical afflictions – in the mid-Atlantic region, including Maryland and the Chesapeake Bay. In particular, he says he will explore the prospects of outbreaks of cryptosporidium, which causes extreme and sometimes fatal diarrhea. He’s concerned that more severe storms and flooding may increase the likelihood of outbreaks in this region – as occurred in Milwaukee, Wisconsin, last year – because the waterborne disease is resistant to chlorination and can get by filtration systems. He stresses, however, that the research is only just starting and no conclusions have yet been drawn about risks in this area.
Another JHU researcher, Stan Becker, who studies population dynamics, is concerned about the health implications of global climate change in light of the tremendous population increase. “We are in a unique time in the history of this planet in regard to human population growth,” he explained at the November 13th Hopkins symposium. Currently there are approximately 5.7 billion people on Earth, and the number is expected to rise to somewhere between 11.3 billion and 19.2 billion by 2100.
Such a doubling or tripling of Earth’s population is bound to have an impact on the rate of global climate change – and if such rapid change occurs, the health stresses on the human population could be dire.
So what is to be done? Do we stop driving, stop heating and cooling our homes and offices, stop having kids? Obviously, in our democratic society such behavioral changes would have to be voluntary – and such widespread change in habits is difficult to achieve, especially since most people haven’t considered the problem enough to understand it.
In 1994, the academic journal Risk Analysis published a survey of people’s knowledge of global climate change, and the results were enlightening: Folks, even well-educated folks, were woefully ignorant of the issue’s basic elements.
“Laypeople display a variety of misunderstandings and confusions about the causes and mechanisms of climate change,” the authors concluded. “Both the United States and the rest of the world are currently considering policy responses to the issue of climate change which would entail costs and expenditures amounting to trillions of dollars. U.S. society cannot have intelligent democratic debate on these choices unless people are better informed.”
At this point, probably the best step we as average citizens can take to deal with global climate change is to try to understand it. Maybe then we will grow to care about it more. As GWU’s Viterito points out, the “last big hurrah” in terms of public concern about global climate change was in 1990, when the world was especially tuned in to environmental problems. Since then, “everybody said they’re not interested anymore,” Viterito says, particularly because doomsday scenarios are no fun to contemplate.
“The Earth has been coming to an end since about 4,000 B.C.,” Viterito remarks, tongue in cheek, “so people tend to pooh-pooh this. But as the economy gets impacted, then people will start to pay attention again.”
What is needed to get our dander up now about global climate change? Viterito says it will take a climate-related disaster close to home.
“What you need is a humongous drought to hit the Northeast,” he says. “I’ll guarantee we’’ll talk about global warming again.”