Earthweek: a diary of the planet
Urban evolution
Earth’s expanding urban environment has for the first time been found to be driving evolution of various species more strongly than it is occurring in natural settings. A study of more than 1,600 cases around the world reveals that species are evolving in numerous ways to cope with humans’ construction of sprawling population centers. Report co-author Marina Alberti of the University of Washington says that changes in plants and animals because of urbanization include differences in body sizes, shifts in behavior and alterations in the way they reproduce.
Costa Rican ash
Costa Rica’s Turrialba volcano entered a second week of continual eruptions that prompted officials to issue a state of emergency. Accumulating ash shuttered the country’s international airport and forced voltage reduction in transmission lines.
Stronger twisters
Large-scale tornado outbreaks that last one to three days with six or more twisters in close succession have nearly doubled in occurrence over the past 50 years, according to a new report. Computer models had suggested that a warming climate would create such an increase in severe storms. But researchers, led by Joel E. Cohen at the University of Chicago, found that amplification of vertical wind shear within storms, not yet predicted to increase because of climate change, is creating the extreme outbreaks.
Antarctic fracture
A huge iceberg poised to break off from Antarctica could become one of the 10 largest ever recorded. A rift in the Larsen C ice shelf that has been monitored for decades suddenly grew in length by 11 miles over just a couple of weeks in December. Britain’s Project Midas, which has been closely monitoring the ice shelf, says the section is now attached to the Antarctic Peninsula “by a thread” just 12 miles long.
5.3 African drought buster
A parching drought that has threatened wildlife with starvation and thirst in South Africa’s Kruger National Park for several years has been broken by downpours. While the cloudbursts brought flash floods that swamped roads in the park, rangers say the rainfall also breathed life into the worldfamous refuge.
Feline invasion
Feral cats now roam more than 99.8 percent of Australia’s land area, where they are devastating wildlife and otherwise causing a major impact on the country’s ecology, according to a new comprehensive study. Australia is the only continent on the planet other than Antarctica where native species evolved without cats. This makes its indigenous animals extremely vulnerable to felines.