Earthweek: a diary of the planet

For the week ending Friday, Aug. 4.

Warming certainty

Studies find that it is now almost impossible to limit global warming to less than 3.6 degrees Fahrenheit by the end of the century. Scientists calculated the effects of the world’s population growth, the gross domestic product per person and amount of carbon emitted in economic activity. They then projected that there is only a 5 percent chance Earth will warm by less than 2 degrees by 2100. A study also found that a 2-degree warming this century is now “baked in.” This threatens to surpass the amount of warming scientists have warned could cause catastrophic sea level rise, as well as heat waves, floods and drought.

Altered currents

Researchers caution that the melt of Arctic sea ice could cause the primary Atlantic Ocean circulation to weaken by 30 to 50 percent, or even collapse. Scientists calculated that over several decades of shrinking Arctic sea ice coverage, a weakened Atlantic Meridional Overturning Circulation could significantly reduce the amount of heat carried by the currents from the tropics to high latitudes. Other studies have revealed that such a trend could significantly chill the climate of Northern Europe.

Icelandic unrest

Tremors around southern Iceland’s Katla volcano prompted officials to briefly raise the aviation color code alert to yellow, signifying an increased chance of eruption. The seismic swarm coincided with a sudden glacial river flood that could have meant temperatures in the volcano rose. Katla has not erupted violently for 99 years.

Jellyfish boom

Increasing blooms of jellyfish around the world may be caused by the construction of offshore structures such as gas and oil platforms and wind farms. The structures appear to provide jellyfish polyps with something to attach to, increasing chances of survival. Researchers found that the more-frequent moon jellyfish blooms in the Adriatic corresponded with a rise in its number of gas platforms. A construction boom in waters off China could be responsible for the huge increase in Nemopilema nomurai, a growing nuisance to fishermen.

Burmese outbreaks

Myanmar, formerly known as Burma, has asked the U.N. health agency for assistance in combatting an outbreak of swine flu that has killed 13 people and infected about 50 others, mainly around the country’s largest city of Yangon. People across the former Burmese capital have donned surgical masks to ward off infection, and officials warned people to avoid crowded venues. Swine flu is a respiratory disease caused by the H1N1 virus. Infection occurs through contact with pigs or through the air between people. A 2009 outbreak killed about 285,000 people.