NEW ORLEANS — They’re America’s shrimpers, crabbers and oystermen. Peelers, shellers and shuckers. They came to the Gulf Coast as war refugees from Vietnam in the 1980s. After Katrina, they were the very first community to return and rebuild. But just as a sense of normalcy had returned to the community of Vietnamese fishermen, the Gulf Coast oil spill hit.

GOMA, Democratic Republic of the Congo — The streets are corrugated with black volcanic rock, while far above a pool of lava glows red in the night sky. The volcanoes in the eastern Congo, near the border with Rwanda, haven’t caused havoc to air travel like Iceland’s Eyjafjallajokull — in fact, most days in Goma are punctuated by the conversation-stopping roar of planes constantly ferrying aid in or minerals out — but they have killed hundreds of people in recent years and forced tens of thousands to flee.

ISLAMABAD, Pakistan — Pakistan has more than its fair share of pressing challenges to deal with, from rising religious fundamentalism to chronic water shortages and crippling power cuts, but it just added another item to its laundry list of urgent priorities: disappearing forests. Pakistan has few forests to begin with, and they’re vanishing fast. The country has lost a quarter of its natural forest cover over the past two decades and is currently experiencing a deforestation rate of 2 percent a year — one of the highest in the world.

WASHINGTON — President Barack Obama’s invitation to discuss nuclear security issues with leaders from 46 other nations brought Vietnamese Prime Minister Nguyen Tan Dung to Washington this week, but nuclear safety was just part of his agenda. As Vietnam approaches the 35th anniversary of the fall of Saigon, and the 15th anniversary of resumed diplomatic ties with the United States, the two former enemies now look toward each other as economic and strategic partners. And each sees, in the relationship, a potential counterbalance to Chinese power.