Earthweek: a diary of the planet

For the week ending Friday, April 6.

Arctic ice max Arctic sea ice reached its greatest coverage of the year on March 17 at the secondlowest maximum on record. The U.S. National Snow and Ice Data Center said the coverage on that date was 5.6 million square miles, or only 23,200 square miles above the record low set on March 7 last year. Freak warming in February saw temperatures soar more than 45 degrees above normal in some parts of the Arctic. Temperatures at the North Pole rose above freezing for several days even as the polar region was still in perpetual darkness

Evolving immunity Several species nearly sent into extinction by a killer chytrid fungus appear to have evolved with resistance to the pathogen. Their populations in Panama alone have now rebounded to previous levels. A hybrid strain of the fungus has been responsible for numerous die-offs of amphibians worldwide since the 1980s. It’s believed to have emerged because of the global trade in amphibians. While not all species have evolved quickly enough to survive, the deep croaks of frogs and toads are returning to some of the once-quiet streams in Panama, but they are still infected with the fungus.

Whaling season Japan’s whaling fleet returned home after slaughtering 333 of the marine mammals since November. The fleet of five ships operated this season without interference from anti-whaling groups for the first time in seven years, allowing the hunt for minke whales to proceed without disruption. The most aggressive of the campaigners, Sea Shepherd, announced last year it is taking a break from its efforts to thwart Japan’s whaling.

African divide A widening fissure that has appeared for miles across the landscape of Kenya’s Rift Valley has wrecked homes and destroyed a stretch of highway. One family said a crack developed in its concrete floor and started spreading after weeks of rain, floods and tremors. “The cracks run almost in a straight line, so you can project. If you see a crack coming your way, get away,” geologist David Adede said. The East African Rift Valley is splitting the African tectonic plate in two.

Eruption Vanuatu’s Manaro Voui volcano produced fountains of lava and a plume of ash that damaged crops, water supplies and buildings on Ambae Island. The volcano is one of the world’s most dangerous and began erupting in the island nation in September. All of Ambae’s 11,000 residents were evacuated then and had just returned.