The global warming hiatus's irrelevance.

INSIGHTS Edited by Jennifer Sills Retraction IN THE REPORT “Observation of chiral currents at the magnetic domain boundary of a topological insulator” (1), we reported the observation of a chiral current in a topological insulator/ferromagnetic insulator heterostructure. The measure- ment used a superconducting quantum interference device (SQUID) to detect an ac magnetic field that we believed was pro- duced by a current flowing in the sample. Depending on the conductivity of various layers of the sample, a similar signal can arise when electric coupling causes a verti- cal oscillation of the SQUID in the spatially varying magnetic field produced by the magnetism of the sample. We and collabo- rators have subsequently shown that the magnitude, shape, frequency dependence, and backgate-voltage dependence of the signal can be explained by the electric cou- pling artifact (2). Although this does not rule out the presence of chiral edge states in these samples, we cannot state that we have observed them. Thus, we must retract our results. This artifact does not affect other papers that used similar methods to image current in nonmagnetic samples. Y. H. Wang, 1,2 * J. R. Kirtley, 1 F. Katmis, 3,4 P. Jarillo-Herrero, 4 J. S. Moodera, 3,4 K. A. Moler 1,2 * Department of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA. 2 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA. 3 Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. *Corresponding author. E-mail: wangyhv@stanford. edu (Y.H.W.); kmoler@stanford.edu (K.A.M.) REFERENCES 1. Y. H. Wang et al., Science 349, 948 (2015); published online 13 August 2015 (10.1126/science.aaa0508). 2. E. M. Spanton et al., “Electric coupling in scanning SQUID measurements” (2015); http://arxiv.org/abs/1512.03373. Editorial expression of concern IN THE 29 May 2015 issue, Science pub- lished the Research Article “The protein LEM promotes CD8 + T cell immunity through effects on mitochondrial respira- tion” by I. Okoye et al. (1). On 23 October 2015, Science published a Correction to two of the figures in the Okoye et al. paper (2). An investigation into potential errors in the paper is being undertaken by Imperial College London, UK. In light of the con- tinuing investigation, Science is publishing this Editorial Expression of Concern to alert our readers to the fact that questions have been raised about the validity of find- ings in the Okoye et al. paper. Marcia McNutt Editor-in-Chief Published online 10 December 2015; 10.1126/science.aae0548 REFERENCES 1. I. Okoye et al., Science 348, 995 (2015). 2. Science 350, aad6462 (2015). Preventing tropical mining disasters MINING FOR FOSSIL fuels and minerals is penetrating into many of the world’s most remote and biologically important tropical forests. In the Amazon, there are some 53,000 active mining leases (1), and hun- dreds of billions of dollars in new mines are planned across the Congo basin (2). But are extractive industries in the tropics investing sufficiently to prevent environ- mental disasters? The urgency of this question is under- scored by a recent disaster at the Samarco iron ore mine in Minas Gerais, Brazil. Tailing-pond dams burst on 5 November, disgorging 50 million cubic meters of min- eral sludge into the Rio Doce. Hundreds of kilometers of river have been polluted, with potentially devastating long-term conse- quences for aquatic wildlife and hundreds of thousands of local inhabitants, who formerly relied on the river for water and fisheries (3). A disaster of this magnitude in a remote tropical forest would cause a catastrophic loss of hyperdiverse forest, and endanger indigenous tribes. In tropical wet environments, huge quan- tities of rain can fall in short timespans. Tropical mines therefore require specially designed tailing ponds and infrastructure that can withstand massive influxes of water, but the engineering is often inad- equate. This appears to have been the case in the Samarco disaster. Although many nations require mining corporations to pay a bond to be held in escrow for future clean-ups, it is unclear how often or effectively this is being enforced in tropical developing nations. However, prevention is far better than cure. We urgently need a global framework to police the construction, management, and maintenance of key infrastructure in tropi- cal mines. Given that tropical nations are hungry for mining-tax revenues and mining corporations (including Vale, the joint owner of Samarco) are often major contributors to political parties, there will be temptations to overlook these urgent safeguards (4). We propose an independent global authority to fulfill this critical role. Such an authority must be able to temporarily close failing or high-risk mines, and must have mechanisms for reporting to relevant stock exchange listings and financial institutions. Without independently verified security, there is an escalating risk of environmental catastrophe in the world’s tropical regions. David P. Edwards 1 * and William F. Laurance 2 Department of Animal and Plant Sciences, University of Shef eld, S10 2TN, UK. 2 Centre for Tropical Environmental and Sustainability Science, and College of Marine and Environmental Sciences, James Cook University, Cairns, QLD 4878, Australia. *Corresponding author. E-mail: david.edwards@ shef eld.ac.uk REFERENCES 1. N. Alexander, The Emerging Multi-polar World Order: Its Unprecedented Consensus on a New Model for Financing Infrastructure Investment and Development (Heinrich Boll Foundation North America, 2014). 2. D. P. Edwards et al., Conserv. Lett. 7, 302 (2014). 3. H. Escobar, Science 350, 1138 (2015). 4. W. F. Laurance, New Scientist, 16 August, 16 (2008). The global warming hiatus’s irrelevance IN 2009, WE argued that short periods of warming or cooling in the observed global average temperature were inconsequential to conclusions about either the existence or magnitude of anthropogenic climate change (1). Natural variations on inter- annual and interdecadal time scales are combined with the effect of human-forcing factors in the observational record, and it came as no surprise that warming of the climate system is episodic and interspersed sciencemag.org SCIENCE 18 DECEMBER 2015 • VOL 350 ISSUE 6267 Published by AAAS PHOTO: AP PHOTO/FELIPE DANA LET TERS