When it comes to global warming, carbon dioxide is the 800-pound gorilla: it’s the most abundant of the long-lived greenhouse gases that human activities generate. But ounce for ounce, methane (CH4) traps more heat, and it accounts for about 20% of the greenhouse gases produced by human activities. Strangely, though, global methane levels “flat lined” from 1999 to 2006. Read more.

Large, robust, lens-shaped microfossils from the approximately 3.4-billion-year-old Kromberg Formation of the Kaapvaal Craton in eastern South Africa are not only among the oldest elaborate microorganisms known, but are also related to other intricate microfossils of the same age found in the Pilbara Craton of Australia, according to an international team of scientists. Read more.

Chemistry research on caribou teeth may expand Alaska’s archaeological record.

At University of Alaska Anchorage, two students are on an interdisciplinary quest to unlock the anthropological and archaeological importance of caribou teeth.

Yes, caribou teeth.

Anthropology student Nathan Harmston is merging ancient migrations with modern science in his graduate research project. Much like annual tree rings, he said, caribou teeth add a layer each day, acting like a biologic calendar during the tooth’s growth. These layers absorb nitrogen, carbon and strontium isotopes from the environment, showing not just where an animal grazed, but when. Analyzing these stable isotopes in growth lines can turn a tooth into a tracking collar from the past, opening up a world of lost information. Read more.

Research by an international team, led by the University of Bristol, has shed new light on the fate of the ancient people of Rapa Nui (Easter Island). It had been proposed that vast forests of giant palm trees were cut down by the people of Rapa Nui, leaving them among other things without canoes. With no canoes, they could no longer fish, so they ate chickens, rats and agricultural crops. However, Rapa Nui is not a tropical paradise with fertile soils, so crop productivity decreased. This ‘ecocide’ hypothesis attributes societal collapse on Rapa Nui to human overexploitation of natural resources. Read more.