Advances In TechnoLoGy And EduCATioN

Even though the theory of global warming was first introduced in the late 1800s, it was not until the mid-1900s that the theory actually started to gain notice in the scientific community. This was largely due to advances in technology and education. The first major achievement was the development of infrared spectroscopy for measuring long-wave radiation in the 1940s. Through the ability to measure infrared radiation, scientists could determine that atmospheric CO2 was absorbing more infrared radiation (the wavelengths related to heat), which was raising the temperature of the atmosphere. Scientists were able to determine that the wavelength of infrared radiation absorbed by CO2 was different than that absorbed by water vapor. This is significant because, if extra CO2 was not in the atmosphere to absorb those additional wavelengths of energy, they would be lost to space instead of heating the atmosphere. Discovered by Gilbert Plass in 1955, this was like a detec-

What Skeptics of global Warming Are Saying

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Richard S. Lindzen, professor at MIT

He is willing to bet the Earth's climate will be cooler in 20 years than it is today.

Sallie L. Baliunas, astrophysicist at Harvard-Smithsonian Center for Astrophysics

She believes that global warming is a hoax.

Exxon-Funded Skeptics, United States

Since 1990, they have spent more than $19 million funding groups that promote global warming skepticism and $5.6 million to public policy organizations that publicly deny global warming and climate change exist.

Philip Stott, professor at University of London

He questions the knowledge of the IPCC.

Patrick J. Michaels, former professor at University of Virginia

He believes that global warming models are fatally flawed and, in any event, we should take no action now because new technologies will soon replace those that emit greenhouse gases.

Bjorn Lomborg, professor at University of Aarhus, Denmark

He is the author of The Skeptical Environmentalist, in which he argues that a statistical analysis of key global environmental indicators revealed that environmental problems were not as serious as was popularly believed.

Competitive Enterprise Institute, United States

This group wants to "dispel the myths of global warming by exposing flawed economic, scientific and risk analysis."

James Annan, British climate scientist

He says the risks of extreme climate sensitivity and catastrophic consequences have been overstated.

tive getting a fingerprint of a thief; in this case the fingerprint belonged to the CO2 and directly linked the presence of CO2 with rising atmospheric temperatures—or the enhanced greenhouse effect.

Until this time, many scientists argued that the oceans would absorb most of the CO2. In the 1950s, researchers learned that CO2 was able to stay in the atmosphere for about 10 years. The status of the oceans then came into question, as scientists began to wonder just how much the oceans could actually absorb and whether or not the CO2 remained in the ocean or whether it could be transferred back into the atmosphere. They concluded that the oceans could only hold about one-third of the anthropogenic CO2—much less than originally thought.

In 1958, Charles Keeling, a climate scientist, began to track atmospheric CO2 levels in Mauna Loa, Hawaii. Measuring CO2 concentrations ever since, this curve—known as the Keeling Curve—has become the most recognizable worldwide symbol of global warming. The curve shows a downward trend in temperature from 1940 to 1970, but starting in the 1980s, the temperature began to increase steadily. In fact, the rate of increase was so steep that it caught the attention of many scientists— this increase was not like anything that had been experienced before in human history.

By the late 1980s—nearly 100 years after Svante Arrhenius presented his ideas—global warming was finally an accepted theory and it was formally acknowledged that climate was warmer than at any period since 1880. This was a major turning point in the history of global warming. The Intergovernmental Panel on Climate Change (IPCC) was created by the United Nations Environmental Programme and the World Meteorological Organization. The IPCC is made up of more than 2,500 scientists from all over the world and many diverse fields, such as climatology, oceanography, ecology, economics, medicine, physics, geography, and others. It is important to have all these disciplines involved because global warming's reach will be so wide that it will involve many sectors that must work together to keep our world healthy. The IPCC is a prestigious group that is considered the largest peer-reviewed scientific cooperation project in history. They have released four reports on climate change to date, the most recent in 2007.

What Supporters of Global Warming Are Saying

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Dave Stainforth, climate modeler at Oxford University

He says, "This is something of a hot topic, but it comes down to what you think is a small chance—even if there's just a half percent chance of destruction of society, I would class that as a very big risk."

Dr. Rajendra Pachauri, chairman of the IPCC

He says that he personally believes that the world has "already reached the level of dangerous concentrations of carbon dioxide in the atmosphere" and called for immediate and "very deep" cuts in the pollution if humanity is to "survive."

Drew Shindell, NASA Goddard Institute for Space Studies

He believes global warming will cause serious drought in some areas. "There is evidence that rainfall patterns may already be changing. If the trend continues, the consequences may be severe in only a couple of decades."

James Overland, NOAA oceanographer

Believes that by 2050, the summer sea ice off Alaska's north coast will probably shrink to half of what it was in the 1980s. This will have a profound effect on mammals dependent on the sea ice, such as polar bears, which could become extinct.

Ilsa B. Kuffner, USGS

Says oceans are becoming more acidic due to rising CO2 in the atmosphere. This, in turn, is destroying the world's coral reefs.

Shea Penland, University of New Orleans, coastal geologist

Mr. Penland, who died in March 2008, said the rate of sea level rise has increased significantly over recent years and warns, "We're living on the verge of a coastal collapse."

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What Supporters of Global Warming Are Saying

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World Wildlife Fund

One of their top priorities is to limit global warming and reduce emissions of carbon dioxide. "If we want to have something left to protect at all, the managers of protected areas need to assess the climate change impacts and prepare their parks for the worst."

James E. Hansen, director NASA GISS

He says, "As we predicted last year, 2007 was warmer than 2006, continuing the strong warming trend of the past 30 years that has been confidently attributed to the effect of increasing human-made greenhouse gases."

Terrence Joyce, Woods Hole Physical Oceanography Department

Concerning changes to the ocean conveyor belt, he says, "It could happen in 10 years. Once it does, it can take hundreds of years to reverse." He is alarmed that Americans have yet to take the threat seriously. In a letter to the New York Times last April he wrote, "Recall the coldest winters in the Northeast, like those of 1936 and 1978, and then imagine recurring winters that are even colder, and you'll have an idea of what this would be like."

Today, scientists are focusing on computer modeling to try to predict the future of climate change. If scientists can accurately model the environment, they can predict future temperatures. But climate modeling is not simple and without its uncertainties. Some scientists have questioned the consistency of readings from ocean stations, satellites, and other remote stations. Climate forecasting is still in its infancy and current models still must rely on relatively sparse databases—globally collected temperatures only go back about 100 years. In some vital areas, such as the effect of cloud cover on global warming, uncertainties have grown as climatologists have attempted to model them due to their complex behaviors (short life span, rapid movement, and unpredictability).

According to Gerald North at Texas A&M University in College Station, "It's extremely hard to tell whether the models have improved in the past five years." Climate modeler Peter Stone from the Massachusetts Institute of Technology states, "The major [climate prediction] uncertainties have not been reduced at all."

Peter Stone also remarks that "We can't fully evaluate the risks we face. A lot of people won't want to do anything. I think that's unfortunate. Greenhouse warming is a threat that should be taken seriously." Possible harm could be addressed with flexible steps that "evolve as knowledge evolves. By all accounts, knowledge will be evolving for decades to come."

The following are three basic challenges in climate modeling:

(1) detecting a warming of the globe

(2) attributing that warming to rising levels of greenhouse gases

(3) projecting warming into the future

"The detection problem seems to be almost solved," says climatolo-gist David Gutzler of the University of New Mexico in Albuquerque, referring to the IPCC's 95 percent confidence level that the Earth has warmed; its conclusions drawn partly from climate modeling.

The IPCC's report states that confidence in climate models has increased. Jerry D. Mahlman, former director of NOAA's Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey, agrees. He states, "I'm quite comfortable with the confidence being expressed."

Original problems with models included the following: satellites acquiring temperature measurements of the atmosphere instead of the Earth's surface, the inability to capture daily temperature ranges, the inability to model cloud dynamics, and the inability to capture increased nighttime temperatures. Today, satellites have been calibrated to acquire temperatures from the Earth's surface. In addition, modeling climate processes, such as ocean heat transport, are more realistic.

Fudge factors that artificially steadied background climate have been eliminated and weather events such as El Niño are now more realistically represented. Improved models are also being driven by better designated climate forcings, such as variability in solar output and volcanic emissions of particulates into the atmosphere.

According to Jeffrey Kiehl of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, "We have made progress, but sometimes progress means you learn you need to know more." In particular, he refers to the pollutant hazes created by aerosol particles from wildfires and fossil fuels. He remarks, "The more we learn about aerosols, the less we know."

Another source of uncertainty is the human factor. According to Jerry Mahlman, "Social uncertainty is hard to discuss because we don't have a clue how people are going to react 30 years from now." As scientists find sensors where measurements may need to be calibrated, adjustments are made and models are rerun and verified. In an ongoing process, the scientific community, as well as the IPCC, strives to keep data integrity in their models so that their models, conclusions, and predictions are reliable, because important decisions that affect all our lives now and in the future are made from them. This is no small feat, however, because of the sheer complexity of climate systems. Because of its complex nature, it reinforces, once again, the need for international cooperation.

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