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ScrutinyWhat's Behind Global Warming
NBC News, May 19, 2000
Evidence of global warming has scientists questioning what is causing it and how it will affect our global forecast. From snow in April to record-breaking heat in May, with tornadoes tossed in between, the atmosphere can cook up plenty of surprises. At the National Weather Service, where they have been keeping records since 1869, officials recorded 1999 as the warmest year yet. These logbooks tell a great deal about the past, but just what it means for the future is still uncertain. Last summer, New Yorkers experienced a drought and record-high temperatures. August brought a torrential rainstorm that caused major flooding. One month later, Hurricane Floyd hit, devastating parts of the area with more flooding. Weather is what we experience everyday, including the heat or possible rain. Climate, however, looks at the bigger picture, studying pattern variations from season to season and year to year. That is where meteorologists are really seeing changes.
Dr James O'Brien, a professor at Florida State University, says that what we are experiencing is climate variability. "It's definitely not global warming," O'Brien said. "The real changes in this country are the El Nino and La Nina changes." El Nino and La Nina conditions are when the Pacific Ocean goes through cycles of heating and cooling. These cycles drastically affect weather all over the world, he said. "So natural causes are making it hot and cold, and man's effect with the greenhouse make it slightly warmer. Where we're going we'll just have to wait and see," O'Brien said.
Scientists at GFDL point to changes in the Arctic Sea ice. Northern climates, sub-Arctic areas like Alaska and other Northern climates, could see changes first. Sea level is rising and permafrost is melting. On the East Coast, many areas could be affected. "Anyone who lives here in Alaska knows that the winters are warmer, in fact, warmer by about 10 degrees Fahrenheit over the last 30 years," said Gunter Weller, a professor at the University of Alaska. Scientists say temperatures are certain to rise as a result of global warming, depending on the level of carbon dioxide. In New York, the levels are worse than in other parts of the country. "That means New York City is worse than New Orleans when it comes to summer heat index," said Mahlman. The number of days above 90 degrees a year could rise from 13 days a year to over 30 days a year. This could mean stress to power grids and potentially more blackouts. Eric Williford, at Florida State, says that this global climate could have an effect on future storms. "Will the sea surface warm? That's probably the key ingredient here. If we have warmer oceans, we have more chance for storms and definitely higher potential for larger storms, intense hurricanes," Williford said.
