As students prepared for their return trips to Duke in the prime of a new spring season, the weather seemed to have different plans, causing delays on the roads and in the air.

Delays and cancellations in northeastern airports affected students flying in from locations across the country, and even some from abroad. Sophomore Chris Perry, for example, said his flight back to North Carolina was delayed in Montego Bay, Jamaica, as a result of delays at the Philadelphia International Airport.

Still, the National Climatic Data Center announced findings last week indicating the warmest winter globally since temperatures were first recorded in 1880.

"I wouldn't put too much in the cold weather on the East Coast the past few weeks," said William Schlesinger, James B. Duke professor of biogeochemistry and dean of the Nicholas School. "Every year has spots on Earth that are warmer or colder than average."

In February, much of the Midwest and the East Coast recorded below-normal temperatures, with parts of New England reaching near record-setting lows, according to weather.com.

Most of these states, however, still ended the climatological winter, lasting from December to February, above or near average temperatures.

Parts of the West Coast joined the United Kingdom, Japan, South Korea, Germany and other regions on the other end of the scale in reaching above normal temperatures, Stu Ostro, senior meteorologist for weather.com, wrote in a Feb. 2 blog post.

Amid heavy debate regarding trends behind global warming, this year's record-setting high temperatures have been used by some experts to support a trend of increasing global temperatures.

The global warming hypothesis suggests that an increase in the release of greenhouse gases has resulted in higher global temperatures over time. These gases are said to work like the walls of a greenhouse, allowing sunlight to enter the atmosphere, but not allowing heat radiation to leave the atmosphere again.

Many researchers and meteorologists consider heightened global temperatures to be indicators of the greenhouse phenomenon, despite regional discrepancies.

"The past few decades have most of the warmest years of the past century, and the averages tend to be getting progressively higher," Schlesinger said. "What matters is the long-term average trend, and that is clearly up-as measured by the average of weather stations, NASA's satellite coverage of the Earth, the melting point of ice in polar regions and other records."

In addition to these long-term trends, evidence of global warming may be observed on a day-to-day basis, Ostro said.

"The challenge is to figure out to what extent and in what ways changes in climate are manifesting themselves as changes in weather," he said.