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- Scientific American The latest news about extraterrestrial life from Scientific American May 28, 2020 - How to Search for Life in Space This article explains how scientists search for extraterrestrial life in space. It explains the techniques used to find potential signs of life, such as searching for planets in the habitable zone of a star, looking for signs of life in cosmic dust and using spectroscopy to search for organic molecules. May 27, 2020 - Could Earth’s Bacteria Survive on Mars? This article investigates whether Earth’s bacteria could survive on Mars. It looks at recent experiments that have shown some species of bacteria can survive in the Martian environment, as well as the challenges of protecting bacteria from cosmic radiation and other dangers. May 26, 2020 - Could We Find Extraterrestrial Life in Our Solar System? This article looks at the possibility of finding extraterrestrial life within our Solar System. It considers which planets and moons might be able to support life, as well as the challenges of detecting life from Earth. May 25, 2020 - Video: The Search for Extraterrestrial Life This video explains the scientific search for extraterrestrial life. It looks at the techniques used to detect

Increasing applied pesticide toxicity threatens plants and insects - successful GREEN

A group of scientists has shown that for plants and insects the applied pesticide toxicity in agriculture has substantially increased between 2004 and 2016. In a paper published in the current issue of Science, the authors show that this pattern is even relevant in genetically modified (GM) crops that were originally designed to reduce pesticide impacts on the environment. “We have taken a large body of pesticide use data from the US and have expressed changes of amounts applied in agriculture over time as changes in total applied pesticide toxicity,” says lead author Ralf Schulz, professor for environmental sciences at the University of Koblenz-Landau, Germany. “This provides a new view on the potential consequences that pesticide use in agriculture has on biodiversity and ecosystems”. The amount of insecticides used in US agriculture has decreased substantially by more than 40% between 1992 and 2016. Fish, mammals, and birds face lower applied toxicities than in the 1990s, because insecticide classes such as organophosphates, which show high vertebrate toxicity, are used less today. Aquatic invertebrates and pollinators, such as honeybees, yet experience the opposite: despite reduced applied amounts, applied toxicity for these species groups has more than doubled between 2005 and 2015. A shift in the insecticides used towards usage of pyrethroid and neonicotinoid insecticides is responsible for this trend. The applied toxicity increases for herbicides as well, alongside the applied amount. In this case, terrestrial plants are facing the highest increase in applied toxicity. Plants and pollinators are ecologically strongly connected. Simultaneously increasing applied toxicities in both groups thus alert to potential strong overall negative effects on plant and insect biodiversity. GM crops have been developed to reduce the dependency of agriculture on chemical pesticide use. The results of the new study, however, clearly reveal that even in the two most important GM crops in the US, corn and soybean, the applied toxicity increases, along with increasing GM adoption, at the same rates as for conventional crops. According to the authors, the results of the study likely apply to many other regions dominated by modern agriculture, though often the data for a thorough evaluation of trends in applied toxicity are not publicly available. Ralf Schulz adds: “These results challenge the claims of decreasing environmental impact of chemical pesticides in both conventional and GM crops and call for action to reduce the pesticide toxicity applied in agriculture worldwide.” Image credit: Renja Bereswill, Universität Koblenz-Landau

Mitigating climate change through alternative control strategies - successful GREEN

Researchers are proposing an alternative strategy for controlling the global carbon-climate system. In a recent study published in the journal Climatic Change, they describe the advantage of using concepts from control theory, in particular closed-loop feedback control.  Scientists are exploring many different options to reduce further atmospheric accumulation of greenhouse gases and dangerous climate change. The diversity of options ranges from planting trees for absorbing more CO2 to injection of aerosols in the atmosphere for reducing incoming solar radiation. The ultimate goal is to manage the entire carbon cycle and the energy balance on planet Earth, an extremely ambitious task with unknown consequences and without a guarantee for success. However, humans are very successful at steering complex systems by using advanced concepts of mathematical control theory. Impressive examples are autonomous transportation vehicles, robotic systems in assembly lines, and congestion regulation in transport and communication networks. Despite their large potential, very few attempts have been made to introduce such concepts to climate science and policy. Researchers from the Max Planck Institute for Biogeochemistry in Jena, Germany, and the University of Washington, USA, have now made an important advance in integrating concepts from control theory in Earth system modeling. Applying control concepts “Climate models are highly complex, and programmed in a way in which it is very difficult to perform abstract mathematical analyses. In our study we developed a mathematical framework to manipulate climate and carbon cycle models so that we can apply formal control concepts”, says Dr. Carlos Sierra, group leader at Max Planck Institute for Biogeochemistry and lead author of the study. Using such concepts, the authors show that the current approach to climate science and policy relies on long-term scenarios of fossil fuel emissions and mitigation. In control theory, this is analogous to open-loop control, in which a system receives instructions of what to perform in order to reach a specific goal without checking whether it has been achieved. Closed-loop control In contrast, the more powerful closed-loop control uses continuous observations to check whether prescribed actions work, and tries to continuously correct deviations from (pre)defined goals. "It is a little like the difference between your washing machine and your refrigerator," explains Sierra. "Your washing machine uses a set of instructions about what to do in which time frame, without checking whether the clothes are already clean or dry enough. This is open-loop control. In contrast, your refrigerator constantly monitors the internal temperature and cools or pauses accordingly, in a closed-loop form." By analogy, the authors show that levels of carbon dioxide in the atmosphere can be controlled using the same mathematical tools used to prevent congestion in communication networks or in traffic. The ocean and the terrestrial biosphere are important sinks of carbon dioxide. They naturally absorb this gas from the atmosphere and store it for long time periods, however with only a limited capacity. As a consequence, when we release more and more carbon from fossil sources, carbon dioxide accumulates in the atmosphere as in a traffic jam. Congestion problems are complex, but control theory provides very effective methods to solve them. Maintaining carbon levels Sierra and colleagues exemplify in their study how to mathematically maintain constant levels of carbon dioxide. “In our model, we apply a control mechanism that only allows carbon emissions based on the natural capacity of the oceans and the terrestrial biosphere to absorb carbon,” Sierra explains. The study by Sierra and colleagues could be the beginning of new concepts and approaches for managing the Earth’s energy balance with tools from control theory. These approaches will rely less on future scenarios, but, for example, on calculations of emission allowances based on current natural conditions, as well as continuous monitoring and rapid adaptation of goals. Image credit: Max Planck Institute for Biogeochemistry