By Jan TenBruggencate
Advertiser Columnist

On this Earth Day, global leaders are increasingly worried that humans are using the world's resources in a way that will make them unavailable to future generations.

The popular term for this is that our actions are unsustainable. It is an issue globally, and here at home as well.

Later this summer, Aug. 26-Sept. 4 in Johannesburg, South Africa, the United Nations will convene its World Summit on Sustainable Development.

Summit Chairman Nitin Desai said the health of the environment needs to take an ever higher place in economic and social decision-making.

"For too long, environmentalists and industrialists alike have focused on a false trade-off between environmental protection and economic growth. Sustainable development recognizes that economic well-being, social development and environmental stewardship are interconnected and must be addressed together," Desai said.

The issues are global, but for almost every part of the globe — including Hawai'i — they are also local.

In the Islands, we face issues of rising sea levels, changes in storm patterns, loss of native forest lands to development and alien species, loss of agricultural lands to nonproductive estates for the rich and other threats. One of the primary threats to our coastal areas is runoff from developed land near the coasts.

The Pew Oceans Commission said the increasing urbanization of coastal areas is a severe threat to nearshore waters throughout the nation. The commission is conducting a review of the country's ocean policies and has just released a report: "Coastal Sprawl: The Effects of Urban Design on Aquatic Ecosystems in the United States."

The effects of developed land on the ocean are many. Developed areas generate garden pesticides, oil from vehicles, litter, fertilizer and dirt that can wash into storm drains that lead to the sea, and end up affecting the marine life of our nearshore waters.

"Abundant research on rivers and estuaries confirms that when impervious surfaces cover more than 10 percent of a watershed, the rivers, creeks, and estuaries they surround become biologically degraded," said Dana Beach of the South Carolina Coastal Conservation League.

For places like Hawai'i, where the shoreline is an important part of our economy, our recreation, and for many of us our very sustenance, it all means paying closer attention to the impacts of what we do on our land to what happens in the sea.

For more about the United Nations sustainability summit, visit the Johannesburg Summit Web site.

Jan TenBruggencate is The Advertiser's Kaua'i bureau chief and its science and environment writer. Contact him at jant@honoluluadvertiser.com or (808) 245-3074.