Features


Hot topic: Global warming by Sherry Bithell


The 2005 Atlantic hurricane season was one for the record books. For example, although Hurricane Katrina in August resulted in the third-highest death toll in U.S. hurricane history, it was only the third-strongest storm of the year. Coming in at No. 2 was Hurricane Rita in late September and at No. 1 was Hurricane Wilma--the most intense tropical cyclone ever recorded in the Atlantic--in mid-October. Then, after the Atlantic hurricane season officially ended on Nov. 30, came Hurricane Epsilon, the year's record 26th named storm and 14th hurricane, and only the fifth to form in the month of December in the more than 150 years that storms have been recorded.

The 2005 season was not an anomaly. Half of the storms on the National Oceanic and Atmospheric Administration's list of the 10 costliest hurricanes since 1900 have hit since 2003--and the list hasn't yet factored in the billions in damage from Katrina, Rita, and Wilma.

Saifur RahmanLoring Professor of Electrical and Computer Engineering Saifur Rahman (Ph.D. electrical engineering '78) is the director of Virginia Tech's Center for Energy and the Global Environment and the Northern Virginia Division of the College of Engineering. His research focus includes energy and the global environment, alternate energy sources, and critical infrastructure assessment and modeling. Rahman also teaches two online courses on alternate energy systems and electrical energy and environmental systems to seniors and graduate students.




Why are more storms inflicting such great damage today? A popular theory is that global warming is to blame. For an expert's take on the issue, Virginia Tech Magazine talked to Saifur Rahman, director of Virginia Tech's Center for Energy and the Global Environment.

The cause

Rahman corrects the notion that global warming is the culprit behind the increased number of hurricanes. "There is no known physical link," he says. "What is widely believed is that the impact of natural events, such as hurricanes and flooding, is probably stronger because of increased atmospheric temperature. This may be strengthening the storms--not causing them but making them worse."

Simply put, today's population uses increasing amounts of energy, releasing higher levels of carbon dioxide (CO2) into the atmosphere. "Today, the world releases about 7 billion tons of carbon in the atmosphere in the form of CO2," Rahman notes. "That number was zero 150 years ago."

Higher concentrations of CO2 in the atmosphere will increase the surface temperature on the Earth, which has been steadily warming for about the past 15 years. "The five hottest years in history have happened since 1998," says Rahman, "and 2005 may be the hottest year ever recorded since 1880, when the earth's temperature readings were first taken."

Records show that in 1850, the atmospheric concentration of CO2 was 280 parts per million. By 2000, that number had grown to 360 parts per million. "If we continue to emit as much CO2 as we have been, the number will grow to 560 parts per million by the end of this century," Rahman predicts. "That will mean the average surface temperature may be 7.5 degrees Fahrenheit higher than it is today."

And the effects

EarthThe effects of global warming on hurricanes were demonstrated repeatedly this year. Making less of an immediate impression, yet having a greater impact, is the decreasing ice coverage in the North Pole.

Between 1979 and 2003, ice coverage in the summertime dropped by a third. By not reflecting as much sunlight as would snow-covered land, the now-bare or vegetation-covered land absorbs the sunlight, raising the Earth's temperature and leading to further melting of ice. The effect is a cycle that will not only perpetuate global warming but harm plant and animal life accustomed to cooler temperatures, including fish, which in turn will have an impact on fishing--a major food source and a livelihood.

Another consequence is that when melting ice and snow cause the ocean and sea levels to rise, several countries, such as the Netherlands and Denmark, will see increased flooding. National Geographic News reported in September 2001 that "global warming is expected to cause the seas to rise by somewhere between four inches (ten centimeters) and three feet (one meter) during this century."

Charting a new course

The million-dollar question, then, is if the trend of global warming can be reversed. The short answer: no. "When CO2 goes in the atmosphere, it stays there for a 100 years," Rahman says. "It will take that long to recycle, so to speak."

There is good news, however. "The concentration build-up cannot be reversed but it can be slowed down," explains Rahman. "If we can take actions to reduce the CO2 concentration in the atmosphere by either burning fewer fossil fuels or somehow capturing the CO2 that it released from burning fossil fuels, we can slow down this projected growth. That is the whole philosophy of the Kyoto Protocol."

As of September, 156 countries had signed onto the Kyoto Protocol. Notably, the United States was not one of them. Instead, the current administration is focusing on energy-efficiency measures that would not require consumers to restrict their electricity use or driving habits but would burn less fuel, limiting the amount of CO2 produced. Rahman says that these measures are feasible.

"The bottom line is that to reduce or shrink the amount of CO2 emitted, we need to use energy-efficient devices, number one, and number two, find alternate energy sources that are carbon free, such as nuclear and renewable energy sources." However, he adds, one concern is that developing countries simply don't have the technology or the resources to implement alternate energy solutions.

Is it realistic to think that a global effort will be made to reduce the amount of CO2? "Europeans are fully on board with accepting the fact that carbon emissions have to be reduced," says Rahman. "Large developing countries such as China, India, and Brazil do realize their major contributions to CO2 emissions but are waiting to see what the industrialized world will do to share energy-efficient technologies."

Most promising, he feels, is the president's recent change in stance on this policy. "According to his statement at the G-8 summit in Scotland [in June], President Bush now agrees that human activity is the cause of the environmental changes," Rahman reports. "This is a hopeful sign."

What lies ahead?

In terms of a timeframe for a global reduction of carbon emissions, Rahman says, "Given the history and the awareness of the world on the climate-change issue, I believe that by 2010, there will be agreement around the world as to what needs to be done. Ten years from now, we'll see significant action on the part of the developing and developed world to take actions. That means more proactive use of renewable energy sources and a more proactive attitude toward going after high-efficiency energy conversion and end-use devices."

Now that today's policymakers are more accepting of the need for change, Rahman wonders what tomorrow's movers and shakers will do. "What is the young generation thinking about this topic? If you stop students on the Drillfield and ask about this issue, what do they know?"

Based on his experience, today's students have some interest in the subject. "I teach a senior-level elective class called Alternate Energy Systems. This spring, I had 112 students, making the class the largest senior elective at Virginia Tech," he says. "To me, this says that there are a good number of students who are concerned about this issue and want to learn what alternate energy sources they can explore."