The temperature's rising

Published April 22, 2007

Times environmental writer Craig Pittman addresses some of the basics of global warming.

Is global warming real?

Yes. The National Academies of Science, an independent research panel created by Congress, reported last year that the last few decades of the 20th century were warmer than any comparable period in the last 400 years. Evidence shows that many locations were warmer during the past 25 years than during any other 25-year period since 900.


How do we know that?

The evidence comes from tree rings, boreholes, retreating glaciers, corals, ocean and lake sediments, ice cores, cave deposits and other "proxies" of past surface temperatures. In central England, there are written temperature records going back to 1659, and they show 2006 as the warmest year ever in that region.


For heaven's sake, baseball games were snowed out this month. How can the globe be getting warmer?

Short spans of time say nothing about global warming. For example, winter temperatures across the United States were average, but the average temperature across the globe was the highest on record, according to the National Oceanic and Atmospheric Administration. Overall, the global mean temperature has increased about 0.4 degrees F over the past 25 years, and it's projected to rise 3 to 7 degrees F over the next century. Some areas are warming up faster than others. The arctic surface air temperatures are warming roughly twice as fast as the global average, according to NOAA.


Is this merely a natural cycle or are there human causes?

It's us. The National Academies reported in 2001 that this big warming trend is "a result of human activities." A U.N. group, the International Panel on Climate Change, came to the same conclusion. Among the other groups that agree: the American Meteorological Society, the American Geophysical Union and the American Association for the Advancement of Science.


Why should I care?

The U.N. group says that global warming will cause species extinctions to mount, water shortages to spread and droughts and floods to become more frequent. There may be more pollen allergies, mosquito-borne diseases and heat-stroke deaths. Hurricanes will begin to hit Florida like we're a pin in the world's most popular bowling alley. The insurance companies are already factoring that into their rates. And as the polar ice caps melt, the seas rise - a reasonable estimate is 20 inches by 2100 - which ought to concern people who live in a state nearly surrounded by water.


What's causing this?

Mostly it's carbon dioxide (CO2). Since the Industrial Revolution of the 1700s, we've been putting out way too much of it, and it's collecting in the atmosphere, trapping the sun's heat like the glass roof of a greenhouse. In 2005, global atmospheric concentrations of CO2 were 35 percent higher than they were before the Industrial Revolution.


What are the biggest sources?

The United States produces more carbon dioxide than any other nation, mostly from coal-burning power plants (40 percent) and passenger vehicles (20 percent), according to the Environmental Protection Agency. U.S. greenhouse gas emissions linked to global warming increased 16 percent over the most recent 15-year period, the EPA reported last week.


What is the government doing about this?

According to the U.S. Supreme Court and several states, not enough. Massachusetts sued the EPA for refusing to regulate carbon dioxide emissions under the Clean Air Act. The EPA argued it lacked the authority, but the Supreme Court ruled that its excuses were "arbitrary, capricious, and otherwise not in accordance with law." Meanwhile, California, which produces more carbon dioxide than some countries, passed its own law requiring major industrial producers of such gases to reduce emissions 25 percent by 2020. Other states have imposed similar caps.


Won't anything we do be offset by other countries?

That's President Bush's argument for opposing the Kyoto treaty calling for mandatory emissions cutbacks: It exempts 80 percent of the world, including major population centers such as China and India, from compliance. Instead he has called for voluntary emissions controls. China is set to overtake the United States as the biggest source of greenhouse gases, possibly as early as this year. Last week Reuters reported that China's leaders have finally proposed a plan to cut carbon emissions by 40 percent by 2020 - but like Bush, they're still resisting mandatory controls. Columnist Thomas Friedman, in a New York Times Magazine piece (nytimes.com), says alternative energy sources become viable in the developing world only when they match the "China price." That "is basically the price China pays for coal-fired electricity today because China is not prepared to pay a premium now, and sacrifice growth and stability, just to get rid of the CO2 that comes from burning coal."

"The 'China price' is the fundamental benchmark that everyone is looking to satisfy," Curtis Carlson, CEO of SRI International, which is developing alternative energy technologies, told Friedman. (SRI has opened a branch in St. Petersburg.) "We have an enormous amount of new innovation we must put in place before we can get to a price that China and India will be able to pay. But this is also an opportunity."


Is there some way to give everyone an incentive to produce less carbon dioxide?

Yes, but if you had trouble grappling with the IRS last week, this proposal may leave you feeling hot under the collar. Some experts are touting a "carbon tax" as the ideal solution to reducing emissions.

"A carbon tax would be paid whenever a molecule of carbon dioxide is emitted to the atmosphere by burning fossil fuels," wrote William Schlesinger, dean of the Nicholas School of the Environment and Earth Sciences at Duke University.

"Utilities would pay it based on their smokestack emissions and pass the cost to consumers in their monthly electric bill. Each of us would pay it when we fill up with gasoline, based on the content of fossil carbon in the fuel."

By taxing carbon emissions, proponents argue, the government would make other forms of energy more competitive on price.


Has anything like this ever worked before?

Sort of. A scheme was created years ago for trading in the pollution that causes acid rain. While acid rain hasn't gone away, it isn't the looming crisis it was 20 years ago. Rather than a carbon tax, the government could create "offsets," which cap emissions at a certain level and allow a cleaner factory to sell its pollution credits - in effect, sell the pollution it is not creating to a company that isn't clean enough yet and will pay for the right to pollute. Those offsets are bought and sold on an open market.


Are there any political advantages in trying to tackle global warming? Sure. As Friedman points out, if we wean ourselves off those fossil fuels that produce greenhouse gases, we will be cutting off the flow of money to hostile states that rely on oil revenues. And the U.S. economy could benefit from creating new markets for high-tech green solutions.


Further reading

The U.N. Intergovernmental Panel on Climate Change report is at www.ipcc.ch.