The human system, driven largely by economic decisions, has profoundly affected planetary ecosystems as well as the energy supplies and natural resources essential to economic production. The challenge of sustainability is to understand and manage the complex interactions between human systems and the rest of nature. This conceptual article makes the case that meeting this challenge requires consilience between the natural sciences, social sciences and humanities, which is to say that their basic assumptions must be mutually reinforcing and consistent. This article reviews the extent to which economics is pursuing consilience with the sciences of human behavior, physics and ecology, and the impact full consilience would have on the field. The science of human behavior would force economists to redefine what is desirable, while physics and ecology redefine what is possible. The challenges posed by ecological degradation can be modeled as prisoner's dilemmas, best solved through cooperation, not competition. Fortunately, science reveals that humans may be among the most cooperative of all species. While much of the mainstream economic theory that still dominates academic and the policy discourse continues to ignore important findings from other sciences, several sub-fields of economics have made impressive strides towards consilience in recent decades, and these are likely to change mainstream theory eventually. The question is whether these changes can proceed rapidly enough to solve the most serious problems we currently face.

Manufacturing in areas of the developing world that lack electricity severely restricts the technical sophistication of what is produced. More than a billion people with no access to electricity still have access to some imported higher-technologies; however, these often lack customization and often appropriateness for their community. Open source appropriate technology (OSAT) can overcome this challenge, but one of the key impediments to the more rapid development and distribution of OSAT is the lack of means of production beyond a specific technical complexity. This study designs and demonstrates the technical viability of two open-source mobile digital manufacturing facilities powered with solar photovoltaics, and capable of printing customizable OSAT in any community with access to sunlight. The first, designed for community use, such as in schools or makerspaces, is semimobile and capable of nearly continuous 3-D printing using RepRap technology, while also powering multiple computers. The second design, which can be completely packed into a standard suitcase, allows for specialist travel from community to community to provide the ability to custom manufacture OSAT as needed, anywhere. These designs not only bring the possibility of complex manufacturing and replacement part fabrication to isolated rural communities lacking access to the electric grid, but they also offer the opportunity to leap-frog the entire conventional manufacturing supply chain, while radically reducing both the cost and the environmental impact of products for developing communities.

Dear reader,

We are proud of Challenges in Sustainability's (CiS) fruitful start. A variety of quality research articles, edi- torials and notes have been published on a range of themes and topics, including sustainability governance [1], improved cookstoves [2], [3], the potentials of 3-D printing in the global South [4], and the need for con- siliences between the natural and social sciences and the humanities [5], to name just a few. Furthermore, despite the journal's short history, we are pleased with its high visibility, where numerous articles have been viewed or downloaded over 1200 times since publication. The high exposure rate and the quality of publications affirm our aspirations for stable growth and development in the future.

Much of CiS's early success can be acredited to the competent and devoted administrative, managerial and editorial staff. We must first begin by thanking former Editor-in-Chief, Jürgen Kropp, for his work in estab- lishing and placing the journal on a solid footing for the future. Much of the success can also be attributed to the diverse, but impressive, editorial group with competencies in a multitude of sustainability-relevant areas, nor must we forget the devoted managerial and administrative staff at the journal. Thank you all!

Pathway Forward

Notwithstanding our progress, we will continue to work diligently to place CiS at the forefront of sus- tainability knowledge dissemination, not as a highbrow and inaccessible outlet for academic research and discourses on sustainability; our intentions, rather, are to promote the journal as an innovative forum for cutting-edge research, opinions and notes on sustainability (science).

The first step in this process is an updated focus and scope [6] which, we feel, better encapsulates the changing nature and the state of the art of today's sustainability research and the myriad debates and discourses that surround it. In addition to the journal 's timely review process for knowledge prompt dissemination to wider audiences, we will also work actively to promote special issues on specialized cutting-edge themes in the field. Discussions are already underway on topic areas. Furthermore, we will work to promote CiS as a novel instrument for the promotion of alternative forms of knowledge dissemination, e.g., short films [3], forms that are likely to catch the attention of the new generation of savvy multimedia consumers and decision-makers, both in- and outside of academia.

Finally, we will strive to be an innovative forum to link knowledge on sustainability to action. Because CiS is open access, it has the potential to reach broader audiences. Librello, our publisher, leads the change in academic publishing where large scientific journals and publishing houses historically played an important role in science by creating a network for the cir- culation of information. However, in the digital era, the traditional network can actually work against the exchange of information by means of high subscription rates and pay-per-view barriers. As one reaction, a boycott against Elsevier was started in 2012; it now counts roughly 15000 scholars [7].

Open access publishers have increased in number rapidly, contributing to the free-availability of knowledge. Nevertheless, the open access system has an intrinsic problem: the revenue of a company is propor- tional to the number of its publications.Several publishers of dubious reputation have been surfing on this wave and taking advantage of an academic market, which pressures the scholar toward productivity indices based on the number of his/her publications [8], [9].

Librello is an environment sponsored and supported by scholars and their institutions. Our membership program allows us to keep the decision of publication from any economic pressure, and we rely on our editorial team of experts to take decisions impartially. Our system also benefits the authors, since the annual membership fee covers multiple submissions. We aim at working closely together with scientists and experts outside academia, creating and establishing this community-based channel of science dissemination and advocacy, postulating solutions towards a more sustainable society.

Although the trend in manufacturing has been towards centralization to leverage economies of scale, the recent rapid technical development of open-source 3-D printers enables low-cost distributed bespoke production. This paper explores the potential advantages of a distributed manufacturing model of high-value products by investigating the application of 3-D printing to self-refraction eyeglasses. A series of parametric 3-D printable designs is developed, fabricated and tested to overcome limitations identified with mass-manufactured self-correcting eyeglasses designed for the developing world's poor. By utilizing 3-D printable selfadjustable glasses, communities not only gain access to far more diversity in product design, as the glasses can be customized for the individual, but 3-D printing also offers the potential for significant cost reductions. The results show that distributed manufacturing with open-source 3-D printing can empower developing world communities through the ability to print less expensive and customized self-adjusting eyeglasses. This offers the potential to displace both centrally manufactured conventional and selfadjusting glasses while completely eliminating the costs of the conventional optics correction experience, including those of highly-trained optometrists and ophthalmologists and their associated equipment. Although, this study only analyzed a single product, it is clear that other products would benefit from the same approach in isolated regions of the developing world.