Hawaii's future may be decided not at the state Capitol or in local communities but at a meeting some 8,000 miles from our islands. This December, international representatives are gathering in Copenhagen to hammer out a binding agreement to rein in global greenhouse gas emissions — emissions scientists blame for global climate change. Hawai'i ought not to let the opportunity pass without a say.

That's why we are speaking out by coordinating the statewide "Blue Line Project" this Saturday. In a globally unprecedented action, thousands of students statewide will be literally drawing the line on climate change. Using blue chalk, students from schools statewide will draw a line that indicates the extent of flooding from more than three feet of sea level rise. That's the amount of sea level rise that these students could see in their lifetimes.

The Blue Line Project is one of a number of events this Saturday that are part of a larger international effort coordinated by the "350.org" campaign. The events are to raise awareness of the most important number for the Earth's climate future, 350, which represents a "safe" target for the concentration of carbon dioxide in our atmosphere in parts per million.

Global warming continues without pause. Just this summer, June through September was the hottest ever measured, and NASA predicts a new global temperature record will be set within two years. New discoveries reveal that today's carbon dioxide concentration (almost 390 parts per million) is the highest in 15 million years. At that time sea level was 75 to 120 feet higher, and temperatures were 5 to 10 degrees Fahrenheit hotter.

The Earth's temperature and sea level go hand in hand. The British Antarctic Survey reports that "many glaciers along the margin of the Greenland and Antarctica ice sheets are accelerating and, for this reason, contribute increasingly to global sea level rise." Satellites show that glacier acceleration now reaches all latitudes of Greenland and has intensified at key Antarctic sites, thanks in part to warm ocean water. Between 2002 and 2009 ice loss from both Greenland and Antarctica more than doubled. And the global ocean temperature this summer was the hottest on record. Water expands when the ocean gains heat, contributing to global sea-level rise.

Is over three feet of sea level rise this century likely? Last year in the journal Science, researchers summed the components that make up sea level rise, including an assessment of glacier acceleration. They concluded that global sea level could reach 2.6 to 6.6 feet above present by 2100. Using a different methodology, another report (also in Science) estimated a rise between 1.6 and 4.6 feet. The International Panel on Climate Change estimated a rise of 0.6 to 1.9 feet by 2100; however, they specifically excluded any approximation of glacier acceleration, a process already adding 0.6 feet per century to sea level. Additionally, IPCC computer models underestimate current sea level rise by 0.5 feet per century.

Last year California Gov. Arnold Schwarzenegger ordered all resources agencies to complete a sea level rise assessment. Their study examined the impact of 4.6 feet of sea level rise. California officials now know the schools, hospitals, roads, wastewater treatment plants, waste sites, and other critical locations that are at risk of marine inundation. They are considering new policies in light of this information.

It seems only prudent to ask what portion of the Hawai'i community is at risk. Makai of the blue line is the zone especially vulnerable to flooding by sea level rise. How will we manage and adapt to this threat? What infrastructure and ecosystems are at risk? What will happen to the dozens of vulnerable shoreline communities?

The chalking of the blue line Saturday is not simply symbolic. The line represents the future we are leaving these students — and it may be the best case scenario unless a strong international agreement is reached this year.

As islanders, we have an obligation to help world leaders understand the consequences of their choices when forging a new climate agreement. We can help shape this critical discussion.