Ten days ago Foursquare reached the two-million-users landmark, just three months after it had reached the one-million mark. A week earlier, the company received $20m in venture capital from a who's who of Silicon Valley luminaries. It appears the trajectory for Foursquare is only upwards. But as the critical mass of Foursquare users swells and intensifies over the coming months and years, the concerns over privacy are likely to magnify. In June, Webroot, a Denver-based internet security firm, surveyed 1,645 users of "geo-location-ready mobile devices", including 624 in the UK: 29% said they shared their location with people other than their friends; 31% said they accepted a friend request from a stranger; and, yet, 55% still said they were worried about their loss of privacy.
Thijs Versloot on 19 Feb 14The researchers used a global climate model to show that if an extreme emissions pathway -- RCP8.5 -- is followed up until 2035, allowing temperatures to rise 1°C above the 1970-1999 mean, and then SRM (Solar Radiation Management) is implemented for 25 years and suddenly stopped, global temperatures could increase by 4°C in the following decades.
Athanasia Nikolaou on 19 Feb 14Nice quantitative study. They treat the problem within the full uncertainty range of climate sensitivity parameter (much uncertain), very complete. However, at SRM ceasing, after an initial positive spike of Radiative Forcing, the rate of warming seems to return to rates predicted for the non-geoengineering case: "The 20-year temperature trends following SRM cessation are 0.2−0.6 °C/decade for the range of climate sensitivities (figure 5), comparable to those trends that occur under the RCP8.5 scenario without any SRM." I am actually working on a similar idea for deliberate Mars terraforming: aiming to cool the planet down before we introduce a positive Temperature raising feedback with greenhouse gases, maybe could be more efficient than warming itself.
