BAUXITE TO ALUMINUM: ADVANCES, AUTOMATION, AND ALTERNATIVE PROCESSES Aluminum Production in the Times of Climate Change: The Global Challenge to Reduce the Carbon Footprint and Prevent Carbon Leakage GUDRUN SAEVARSDOTTIR , 1,5 HALVOR KVANDE, 2 and BARRY J. WELCH 3,4 1.—Department of Engineering, Reykjavik University, 101 Reykjavı ´k, Iceland. 2.—The Norwegian University of Science and Technology, Trondheim, Norway. 3.—University of New South Wales, Sydney, Australia. 4.—Welbank Consulting Ltd, Whitianga, New Zealand. 5.—e-mail: gudrunsa@ru.is This paper addresses the global challenge of greenhouse gas emissions facing the aluminum industry. The demand, production and use of aluminum are increasing and so are the emissions. From bauxite mine to aluminum ingot, the total global average emissions vary somewhat in the literature, but most reported values are now between 12 and 17 metric tonnes of CO 2 -equivalents per tonne of aluminum, depending on the various estimates and assumptions made. Two-thirds of these gases are emitted because the electricity used for electrolysis is produced from fossil fuel sources, mainly coal but also natural gas. Reduction of these emissions is now the main environmental challenge for the aluminum industry. Globally, the best result is obtained by maximizing aluminum production using green electrical energy from renewable sources. Aluminum production is categorized as an activity at very high risk of carbon leakage, which occurs when there is an increase in carbon dioxide emissions by new production in one country as a result of ceased production with emissions reduction in a second country with a strict climate policy. INTRODUCTION The world is now pushing for a low-carbon future. The global aluminum industry, from bauxite mine to aluminum ingot, has a challenge to reduce CO 2 emissions and the greenhouse effect that these emissions may have on global warming and climate change. These emissions come both directly from the production processes and indirectly from the electric energy used to power it. The emissions are increasing because of the growing demand for aluminum and the limited supply of electrical energy generated from renewables. Many countries are taking a responsible approach to the impact of global warming, and taking actions to minimize their national footprint. Meanwhile, the public and governments rightfully demand reductions of green- house gas emissions, thus requiring strong actions from the aluminum industry in the coming years. While being commendable, in some instances, it can raise the possibility of carbon leakage, an expression that refers to the transfer of industrial production from countries with strict regulations on emissions towards regions with less restriction, thus relocat- ing the process-related emissions. In the case of aluminum, which is deemed at a very high risk of carbon leakage, this may lead to significantly increased total emissions, as most new capacity is added based on an energy mix dominated by fossil fuels. This paper presents an analysis of the smelt- ing trends in order to discuss the possibilities to reduce the overall greenhouse gas emission rate from the aluminum industry. WHAT IS ALUMINUM USED FOR? Aluminum belongs to the so-called light metals with its density of 2.7 kg/dm 3 at room temperature. This is only about one-third of the density of iron Halvor Kvande—emeritus professor at The Norwegian University of Sci- ence and Technology. JOM https://doi.org/10.1007/s11837-019-03918-6 Ó 2019 The Minerals, Metals & Materials Society