Campaigners branded a declaration signed off by 190 countries at the sustainable development summit in Rio de Janeiro an “epic failure”, The Guardian reported. The 10-day conference involving 45,000 people produced a plan to set sustainable development goals, promote a green economy, improve food security and more, but activists and many politicians said it lacked the detail and ambition needed to tackle the world's pressing environmental and social problems.

East Asia's status as the world's “extinction hotspot” was confirmed in the new Red List of Threatened Species, unveiled in Rio, the  BBC reported. Snakes such as the king cobra, the world's largest venomous serpent, are increasingly threatened by hunting for meat, skin and the pet trade, according to the International Union for the Conservation of Nature, which compiles the list.

UN secretary general Ban Ki-moon launched a “Zero Hunger Challenge” at the Rio+20 conference, calling on politicians, business and civil society to boost efforts to ensure food security for all, The Guardian wrote. Ban said an estimated 1 billion people still go to bed hungry each day and outlined a list of five objectives, including 100% access to food all year round and an end to stunting among children, though no deadline was set for achieving these aims.

The BBC reported that China's imports of crude oil from Iran rebounded in May after the two countries resolved a payment dispute. Beijing imported almost 524,000 barrels per day, a 35% jump from the previous month, despite US threats to impose sanctions on financial institutions doing business with Iran's energy sector.

China's top economic planning body announced that a four-year ban on free plastic bags had saved 4.8 million tonnes of oil and 800,000 tonnes of plastic to date, according to Xinhua. But National Development and Reform Commission official Li Jing said restrictions were still ignored in some areas and that the government planned to boost enforcement.

Oil and gas producers shut down a quarter of their capacity in the Gulf of Mexico as tropical storm “Debby” became the first named storm of this year's hurricane season to disrupt operations, Reuters said. BP and Anadarko Petroleum both said they had closed platforms and evacuated workers as the storm moved towards the US coast.

New research warned that sea-level rise is accelerating three to four times faster along America's densely populated east coast than the country's other coastlines, The Guardian  said. Scientists at the US geological survey at St Petersburg Florida said the results meant the ocean from Boston to New York to North Carolina could see rises up to a third greater than in other parts of the world, increasing the risks of storm surge and flooding.

A giant tortoise dubbed Lonesome George and thought to be the last of its subspecies has died in Ecuador, according to the BBC. Staff at the Galapagos National Park said that George, estimated to be around 100 years old, was found dead by his keeper of 40 years.