FUNAFUTI, Tuvalu — The rising sea is eating at the shores of low-slung Funafuti, a spit of coral and coconut palms in the remote Pacific. Unseen fingers of ocean even reach beneath the sands, surfacing inland in startling places among nervous islanders.
"It used to be puddles. Now it's like lakes," said Hilia Vavae, local meteorologist.
Far to the north in the Marshall Islands, 1,250 miles away, trees are toppling before aquamarine waves. Watching, perplexed, from the edge of a lagoon, teenager Ankit Stephen asked a visitor: "Why is this happening?"
Six hundred miles west on tiny Kosrae, Alokoa Talley pondered the same question. Neighbors are moving their homes up the lush slopes, away from the encroaching Pacific. "I don't know," a government worker said, "but I think it's because of 'green' something."
The "greenhouse effect," climate change, has languished on the world's agenda since the 1970s, a seemingly distant threat. But year by year, inch by inch, it is rising to the top as ocean islets flood, glaciers retreat, Arctic permafrost melts and voices raise new alarms.
"We may already be seeing -- in the increased incidence of drought, floods and extreme weather events that many regions are experiencing -- some of the devastation that lies ahead," U.N. Secretary-General Kofi Annan said in March, when he urged all governments to ratify the Kyoto Protocol to reduce "greenhouse gas" emissions.
That long-stalled 1997 accord is opposed in Washington, where U.S. government and industry say emission controls would handicap the U.S. economy. Now only ratification by Russia can revive it, making this a critical year on the political front in a long, difficult debate over what to do about climate change.
On the scientific front, meanwhile, signs of global warming mount. Like the glass of a greenhouse, carbon dioxide, methane, nitrous oxide and other gases in the atmosphere let sunlight in but tend to warm the Earth by trapping heat it emits toward space. That's scientific fact; the scientific puzzle involves other factors that might lessen -- or worsen -- the warming and what it does to the planet.
Concentrations of carbon dioxide, a byproduct of fossil fuels burned in everything from automobiles to electricity plants, reached record levels in the atmosphere last winter, a Hawaii observatory reported in March.
Then, in April, other U.S. scientists reported that NASA satellite readings showed an average increase in the globe's land surface temperatures of 0.77 of a degree Fahrenheit between 1981 and 1998. This reinforced earlier findings, from ground stations, that global temperatures rose 1 degree over the 20th century.
These rising curves of greenhouse gas and global temperature parallel the analysis of the Intergovernmental Panel on Climate Change, a U.N.-organized network of climatologists and other scientists worldwide.
In a 2001 report, the panel listed as a key finding: "Most of observed warming over last 50 years likely due to increases in greenhouse gas concentrations due to human activities."
If emissions are brought under control too slowly, temperatures could rise an additional 10.4 degrees by the year 2100, the panel said, adding that even with rollbacks in smokestack, tailpipe and other emissions, temperatures could rise 2.5 degrees by the end of the century.
Warming is expected to be unevenly distributed and change regional climates in powerful ways, shifting climate zones hundreds of miles, possibly making farmlands drier, deserts wetter, melting ice caps, intensifying storms, spreading disease to new areas, and raising ocean levels anywhere from 3 1/2 inches to 3 feet by 2100, depending on controls, the panel said.
The seas would rise because water expands as it warms and because of the runoff of ice melt from the continents.
In fact, the oceans have expanded, rising an average 1 to 2 millimeters a year -- up to one inch every 12 years -- during the 20th century. More recently, satellites show "the rise has been highly accelerated" to 3 millimeters a year, said Walter Munk of San Diego's Scripps Institution of Oceanography.
Pacific Islanders aren't alone.
Rising seas are a growing threat from Alaska, where Eskimos are relocating an Arctic island village, to New Orleans and Shanghai -- near-coastal cities already below sea level, sinking on their own, and further endangered by expanding oceans.
Prevailing winds, tidal peculiarities and other factors can make sea levels vary from place to place. At Funafuti, capital of a mini-nation midway between Hawaii and Australia, gauges have shown the sea rising 5 to 6 millimeters a year since 1993, meteorologist Vavae said.
But some islands are subsiding, sinking under their own weight. "In many islands, I think the answer is that both are happening -- subsidence and rising levels," said Roger Lukas, a University of Hawaii oceanographer.
Similarly uncertain: What will a swelling ocean do to Funafuti?
