In the world of environmental regulation, where the hope is to write rules that both industry and science can live with, few areas are as contentious as fishing.

The Obama administration called Thursday for a comprehensive national system for regulating the use of federal waters along the nation

When government scientists went looking for mercury contamination in fish in 291 streams around the nation, they found it in every fish they tested, the Interior Department said, even in isolated rural waterways.

Stepping into a major environmental dispute, the Obama administration said Thursday that no new timber-cutting or road project could begin in roadless areas of national forests without the permission of the secretary of agriculture.

In the debate over global warming, one thing is clear: as the planet gets warmer, sea levels will rise. But how much, where and how soon? Those questions are notoriously hard to answer.

Global warming conjures images of rising seas that threaten coastal areas. But in Juneau, as almost nowhere else in the world, climate change is having the opposite effect: As the glaciers here melt, the land is rising, causing the sea to retreat.

The effects of climate change, especially rising seas, threaten trillions of dollars

Last year, a private company proposed "fertilizing" parts of the ocean with iron, in hopes of encouraging carbon-absorbing blooms of plankton. Meanwhile, researchers elsewhere are talking about injecting chemicals into the atmosphere, launching sun-reflecting mirrors into stationary orbit above the earth or taking other steps to reset the thermostat of a warming planet.