A document by AmGeophysicalU-AMA . Click on the document to view its contents.

Ben and Ken: Thanks for offering many great questions, Redditers. We hope that our responses advanced the conversation about global climate change and possible solutions that include climate engineering. We certainly enjoyed this interaction. Signing off, Ken and Ben. Hi reddit! I’m Ken Caldeira and I work on a broad array of issues including the physical climate system, global energy systems, ocean acidification, and geoengineering. With the exception of the ocean acidifcation work, all of our research is based on performing simulations using computer models. Solar geoengineering involves trying to cool the Earth by deflecting some incoming sunlight away from our planet. Studies have shown that actions like putting small particles in the stratosphere could reflect some sunlight away from the Earth, potentially taking our climate back to a point similar to pre-industrial revolution. Of course, we know for sure about only one habitable planet, and toying around with this planet at the required scale would pose great risks – but allowing the Earth to warm from our greenhouse gas emissions also poses grave risks. Given that it is going to take time to transform our energy system into one that does not dump its waste in the atmosphere, what is the best path forward? I’m Ben van der Pluijm and I work in hazards geology and societal impacts of global change. The goal of 2016’s Paris Agreement to limit global warming to 2 degrees C (3.6 degrees F) is ideal, but unlikely from voluntary greenhouse gas emission reductions alone. Building on our remarkable history of engineering applications to overcoming societal challenges, climate engineering should be included as a viable solution for reducing the impacts of global warming. Climate engineering takes two approaches: (1) Carbon dioxide removal, and (2) solar radiation management. The former addresses the cause of climate warming by removing greenhouse gas from the atmosphere (“treat the illness”). The latter offsets the warming effects of greenhouse gases by allowing Earth to absorb less solar radiation (“treat the symptoms”). Given their worldwide impact, planning must occur on a global scale, involving all nations, large and small, rich and poor, and not be limited to a few technologically advanced, wealthy countries. We’re looking forward to answering questions about environmental change and dealing with the impacts for human society, and whether various geoengineering techniques could really be expected to reduce climate damage and decrease damage to both ecosystems and people. We were here from noon to 2 PM EST to answer your questions. Thanks for Asking Us Anything!

A document by AmGeophysicalU-AMA . Click on the document to view its contents.

A document by AmGeophysicalU-AMA . Click on the document to view its contents.

I am Benoit Lavraud, I am permanent staff researcher at the Institut de Recherche en Astrophysique et Planétologie in Toulouse - France, and Editor of Geophysical Research Letters (GRL), a research journal published by AGU focusing on high-impact scientific advances in all major geoscience disciplines. My research topics include the whole chain of phenomena occurring during solar storms between the Sun and the Earth: What are the basic processes of solar storm release? How do solar storm propagate/interact in interplanetary space? How do solar storms trigger geomagnetic activity? What are the key plasma processes controlling this interaction? Can solar and geomagnetic storms be predicted? What are the potential impacts of solar storms on society? I try to tackle these questions through both basic science and instrumentation (ion and electron spectrometers in space). I am Bill Peterson, a research associate at the University of Colorado, Boulder, at the Laboratory of Atmospheric and Space Physics. I have been studying the space weather and the coupling of the ionospheric, magnetospheric, and solar wind plasmas using satellite instrumentation since 1973. I have participated in the design, implementation, and operation of instruments on several NASA missions focused on space weather. I started out studying the physical process that that cause the aurora and the effects of the aurora on the Earth’s magnetosphere and ionosphere. I’m currently working on identifying how these processes differ at Mars using data from the MAVEN spacecraft. I am Andrew Yau, Professor of Physics at University of Calgary, Canada, and Associate Editor of Geophysical Research Letters (GRL), a research journal published by AGU focusing on high-impact scientific advances in all major geoscience disciplines. I am a space scientist. I design satellite instruments such as ion mass spectrometers, and I study the effects of weather in space on the Earth’s upper atmosphere and ionosphere. For example, how and why do solar storms and other space phenomena cause the heating of the upper atmosphere and its escape into space? How does this heating impact Earth-orbiting satellites? How does the solar wind produce the aurora, and the associated electrical currents in the ionosphere? How do these electrical currents affect radio communications - and impact the operations of satellite navigation systems such as my cell phone’s GPS receiver? We’ll be back at 11 am EST (8 am PST, 4 pm UTC) to answer your questions, ask me anything!

I am Alberto Montanari, Professor of Water Resources Management at the University of Bologna - Italy, and Editor-in-Chief of Water Resources Research (WRR), an interdisciplinary journal published by AGU focusing on hydrology and water resources celebrating its 50th this year! WRR is addressing challenging questions for humanity: How is water best managed? How can we secure water all over the world? Is there enough water to feed an ever increasing population? What about the potential impacts of climate change on water resources? How will extreme floods and drought change in the future? Water scientists are addressing these issues in many ways, including using satellites to estimate global water availability and understand how water can be best distributed, and studying the so-called “virtual water trade”, or the virtual displacement of water obtained by exporting food. A Special Collection of WRR looks back on 50 years of research activity in this area and provides a perspective for future research focusing on water systems for the development and benefit of society. Visit the site of WRR here: http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/(ISSN)1944-7973/ I hope to answer lots of interesting questions about water science and management. I will be back to answer your questions at 12 pm ET (9 am PT, 5 pm UTC), ask me anything!