The melting of Earth's glaciers is making the planet fatter, and scientists say that if the trend continues, it could increase flooding, beach erosion and water shortages worldwide.

A team of researchers from Belgium and California has confirmed that Earth is becoming more pumpkin-shaped. They attribute this to the melting of glaciers, which is sending more water into the oceans.

"There's been a melting of the glaciers, a rise in the oceans and a redistribution of the mass of the oceans," said Jean O. Dickey, a geophysicist at the California Institute of Technology's Jet Propulsion Laboratory.

Research at the jet propulsion lab and the Royal Observatory of Belgium shows that melting glacial ice is flowing into the oceans and forcing sea levels to rise - albeit in a small way - along the equator.

Dickey said the study, to be published in today's issue of Science, pinpointed the warmer weather created by El Nino in 1997 and 1998 as a likely short-term cause. But she expects future studies may show that it is also the result of longer-term climate change.

Century of melting

"I feel it's global warming, but we still can't say for sure," she said.

Earth has always been a little thick around the middle because its rotation causes a bulge along the equator, according to Dickey and other scientists. Measurements show the planet's diameter to be about 26 miles longer through the equator than from pole to pole.

A U.S. Geological Survey report released in May says that many of Earth's 160,000 glaciers have been shrinking for more than a century. Other research has shown a correlation between the thinning of the glaciers and increasing global temperatures.

'Glaciers come and go'

Bruce Molnia, a glacial geologist with the U.S. Geological Survey, said up to a quarter of the melting ice worldwide is coming from glaciers in Alaska and the Canadian province of British Columbia.

Molnia, who just completed a survey of 2,000 Alaska glaciers, also said that so much of Earth's water was tied up in glacial ice at the end of the last ice age 18,000 years ago that the oceans off North and South America were 300 feet lower than they are now.

"Glaciers come and go over time," he said.

Earth has been developing a more spherical shape since the end of the last ice age, when rising temperatures melted the glaciers and caused a reshaping of the planet known as post-glacial rebound.

But in August, a team of researchers at NASA Goddard Space Flight Center reported in Science that Earth began getting plumper around the equator beginning in 1998. The researchers bounced laser beams off satellites and measured Earth's surface based on how long it took the beams to bounce back to Earth.

The cause of the changing shape of the planet detected in that study was unknown until Dickey's team analyzed records dating to the 1960s on ice and ocean levels.

The study shows melting ice has raised ocean levels from 4 to 7 millimeters along the equator since 1997, Dickey said. More drastic changes to Earth's shape would affect the rate at which Earth rotates, with an even fatter planet spinning more slowly.

'Significant amount'

Dickey said the findings have ramifications for flooding and beach erosion in tropical areas and coastal communities. It also means a loss of fresh water to the oceans on an increasingly thirsty planet.

"Superimposed over normal sea level rises, it's not an insignificant amount," she said.

Molnia agreed, estimating that the lost water would probably be enough to cover Maryland with at least 200 feet of water.

"It is a significant amount of water lost," Molnia said.