I am Sue Natali, Associate Scientist at Woods Hole Research Center (http://whrc.org/staff/susan-natali/). I’ve been working in the Arctic since 2008, and my research has involved fieldwork across Alaska and in northeast Siberia. I study the effects of climate change on arctic ecosystems and the consequences of these changes for carbon cycling. My research addresses these questions: How do climate change and fire affect permafrost thaw? How do plant communities respond to warmer temperatures and ground thaw? How does permafrost impact soil moisture? What are the impacts of these changes on carbon cycling? What are the implications of permafrost thaw for global climate? I’ll be back at 1 EDT to answer all your permafrost and climate change questions. Ask Me Anything! The AGU AMA series is conducted by the Sharing Science (http://sharingscience.org) program. Sharing Science: By scientists, for everyone. More at sharingscience.agu.org.

I’m Mike Liemohn, a Professor in the Department of Climate and Space Sciences and Engineering (http://clasp.engin.umich.edu/) at the University of Michigan (umich.edu). You’ve probably seen Gravity, The Martian, or The Fantastic Four, so you know that outer space is a dangerous place. But isn’t outer space a vacuum of nothingness? Beyond no air to breathe, what else could possibly hurt you? It turns out…lots! I investigate the physics at work in the almost-nothingness of our solar system. I am also the Editor in Chief of the Journal of Geophysical Research – Space Physics2169-9402/) a leading journal in this field of understanding the Sun, solar eruptions, magnetic storms, the radiation belts, and the aurora at Earth and other planets. I am also currently teaching a very fun course at U-M called SPACE 101: Intro to Rocket Science. I hope to have an engaging discussion with you about the fascinating physics happening in the near-emptiness of outer space, and explore the many ways that space might pose a danger to astronauts, to satellites, or even to power grids here on Earth. I’ll be back at 12 pm ET to answer your questions, Ask Me Anything! The AGU AMA series is conducted by the Sharing Science (sharingscience.org) program. Sharing Science: By scientists, for everyone. More at sharingscience.agu.org.

I am Mike Brudzinski, Professor of Seismology at Miami University in Ohio. I’ve spent most of my career studying earthquakes big and small. The big ones I have worked on are the megaquakes formed at subduction zones where two tectonic plates collide and generate the largest earthquakes and tsunamis on Earth. These earthquakes are rare but potentially devastating, so I have also worked on the much smaller fault tremor and slow fault movements that seems to occur right below and possibly leading up to the really big earthquakes. My colleagues and I just published a paper indicating the likelihood of earthquakes does appear to be higher when the deeper roots of faults are moving slowly. Lately, I have also worked on swarms of small earthquakes triggered by oil and gas activities. My graduate student did a popular AMA when our paper came out linking a series of earthquakes to hydraulic fracturing in eastern Ohio (https://redd.it/2rjqad). This highlights one of my other passions: training the next generation of earth scientists. I have worked on developing courses and teaching modules that follow a strategy I refer to as “active e-learning”. This is where students learn science by actually doing it with computers instead of just listening to me lecture about it. In addition to making classes more engaging and flexible, the transition from student to researcher is more seamless and allows me to work with more students in my research. Lastly, I think science outreach is critical, and I found a fun way to do that recently by helping to measure how much fans shake the Ohio State stadium during football games. I’m looking forward to all sorts of questions about earthquakes, big and small, fast and slow, natural and human induced. And I would love to talk about education and outreach too! And let’s continue the discussion on Twitter @seismohio

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Hi Reddit! I’m Dave Petley, Vice-President (Research and Innovation) at the University of Sheffield in the United Kingdom. I also run the Landslide Blog, which sits on the website of the America Geophysical Union, the World’s largest earth science organisation. I have a strong interest in natural hazards and disasters. For 25 years I have been doing research into landslides, which collectively kill about 14,000 people per year worldwide on average. I’m interested in particular on how landslides occur and on the impacts that landslides have on society. I’ve worked all over the world, including in Europe, the US, Chile, Taiwan, China, Nepal, Pakistan and New Zealand. Landslides are often triggered by a larger event affecting a substantial area, such as a hurricane or an earthquake. As a result I have worked extensively on the anticipation of large disasters and on the management of their impact, as well as coping with the aftermath. For example, I have worked on the impact of typhoons in Taiwan and Hong Kong; on rainfall induced flood disasters in India and Nepal; and on the massive earthquakes in Taiwan in 1999, Pakistan in 2005, China in 2008 and Nepal in 2015. I was the co-author of one of the best-selling textbooks on the management of disasters. I will be back at 12 pm ET to answer you questions, ask me anything!

Hello! I’m Kris Karnauskas, faculty member at the University of Colorado Boulder’s (http://www.colorado.edu) Department of Atmospheric & Oceanic Sciences (http://www.colorado.edu/atoc/) and Cooperative Institute for Research in Environmental Sciences (http://cires.colorado.edu/). I’m also an editor of AGU’s Journal of Geophysical Research-Oceans (http://tinyurl.com/ztaob5k). I lead the Oceans & Climate Lab (http://www.colorado.edu/oclab/), which aims to understand what makes the climate system tick, the role of the ocean in climate, and what are the effects of climate change on marine ecosystems and human society. My team just published a study about some ongoing changes in the Pacific Ocean near the equator (http://tinyurl.com/gohynr9), and what they mean for penguins hanging in the balance. With one of the strongest El Nino events in recorded history peaking just last month, it has been an incredibly exciting year to be an oceanographer and climate scientist! Talk to you soon! I’ll be back at 12 pm EST (9 am PST, 7 pm UTC) to answer your questions, ask me anything!

My name is Bruce Jakosky (http://lasp.colorado.edu/home/maven/about/teampartners/principal-investigator/) from the University of Colorado. I’m the Principal Investigator of the MAVEN mission, and have an interest in the complex volatile system on Mars, reaching from the deep interior to the region that interacts with the incoming solar wind. My name is Dave Brain (http://lasp.colorado.edu/~brain/David_Brain/Home.html), and I’m a member of the science team and an Assistant Professor in Planetary Sciences at the University of Colorado. My research focuses on interactions of the solar wind with planetary magnetospheres and the implications. And I’m Rob Lillis (http://sprg.ssl.berkeley.edu/~rlillis/), a Research Scientist at the University of California at Berkeley and a member of the MAVEN science team. I’m interested in the energy input into the Mars atmosphere that comes from solar storms and the corresponding response of the upper atmosphere. The MAVEN (http://lasp.colorado.edu/home/maven/) spacecraft has been in orbit around Mars for just over an Earth year. We’re getting enough measurements that we’ve now been able to see the general behavior of the upper atmosphere and also its response to a significant solar storm. We’ve determined that atmospheric gas escapes from Mars to space in large enough quantities that this loss probably was a major mechanism for changing the climate on Mars and turning it from a warm, wet environment to the present-day cold, dry environment. We will be back at 2 pm EST (11 am PST, 7 pm UTC) to answer your questions, Ask us anything!

We’re Radley Horton, Lamont Associate Research Professor at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, New York and Sarah Doherty, Senior Research Scientist at the Joint Institute for the Study of the Atmosphere and Ocean at the University of Washington in Seattle. We were both Lead Authors on the recent Climate Science Special Report (http://www.globalchange.gov/content/cssr), which focused on climate change in the U.S. and part of the Fourth National Climate Assessment. We’re here to talk about how our climate is changing, what causes it, and what to expect in the years ahead. We’re looking forward to your questions! We’ll be back at 1pm ET to answer your questions, ask us anything! The AGU AMA series is conducted by the Sharing Science (sharingscience.org) program. Sharing Science: By scientists, for everyone. More at sharingscience.agu.org.

I am Joel Thornton, Professor of Atmospheric Sciences at the University of Washington. My research focuses on microscopic nano-scale particles in the atmosphere, where they come from, and what they do to air quality, weather, and climate. These particles come in many shapes and sizes, from a variety of sources like wildfires, sea spray, desert dust, vegetation, and our own pollution from power plants, diesel trucks, cargo ships and so on. These particles can be toxic to human health, with the smallest more numerous ones getting into our lungs, but they are also good at reflecting sunlight to space, and they are the seeds on which every cloud droplet or snowflake forms so they have an out-sized influence on weather and climate. For example, my colleagues and I recently showed (http://onlinelibrary.wiley.com/doi/10.1002/2017GL074982/full) that lightning is twice as frequent above busy shipping lanes, likely because of the particles emitted in the ships exhaust! Ask me anything about atmospheric particles and how the nano-scale can effect the global scale. Ask me anything! I’ll be back at 12 pm Et to answer your questions, ask me anything! The AGU AMA series is conducted by the Sharing Science (sharingscience.org) program. Sharing Science: By scientists, for everyone. More at sharingscience.agu.org.

I am Sarah Hörst, Assistant Professor in the Department of Earth and Planetary Sciences at Johns Hopkins University. I study planetary atmospheric chemistry and have spent most of my career trying to unravel the mysteries of Saturn’s largest moon Titan and much of my work has been inspired. My group also studies exoplanets, Europa, Saturn, Pluto, and Venus. We are use experiments, models, and analysis of telescope and spacecraft data to improve our understanding of the role atmospheres play in the origin and evolution of life and the habitability of a planet. We are trying to answer questions like how far can organic chemistry proceed in the absence of life? You can learn more about us and our work at www.sarahhorst.com. I hope to answer lots of questions about the solar system and how we study it. I will back at 1 pm ET to answer your questions, See you all soon!

I am Andrew Yau, Professor of Physics at University of Calgary, Canada, and 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 am interested in the effects of weather in space around the Earth - and other planets. For example, how and why do solar storms cause the heating of the upper atmosphere and its escape into space here on Earth? How about on Venus, Mars, and Jupiter? How does the solar wind produce the aurora, and the associated electrical currents in the ionosphere here on Earth? How about on Jupiter and Saturn, which also have an internal magnetic field? I’ll be back at 12 EDT to answer your questions. Ask Me Anything! The AGU AMA series is conducted by the Sharing Science program. Sharing Science: By scientists, for everyone. More at sharingscience.agu.org. Thanks, everyone, for participating in today’s AMA. It has been great fun – I hope my answers to your questions have provided a glimpse of the exciting scientific discoveries about the largest planet in our Solar System, Jupiter, from the NASA Juno mission. Some of these discoveries were reported in the recent Special Issue of the Geophysical Research Letters (GRL) for Juno. I encourage you to check out the GRL website for these discoveries as well as some even newer ones that are in the pipeline: http://agupubs.onlinelibrary.wiley.com/hub/issue/10.1002/grl.v44.10/ Sorry I didn’t have a chance to field many of the other questions. Have a great day!

I am Jill Trepanier, Assistant Professor in the Geography and Anthropology Department at LSU. I’ve been at LSU for five years, and my area of expertise is the understanding of hurricane risk variability. I have been working in the area since 2007 and am fascinated with all things extreme weather. The types of questions I ask include why do hurricanes more frequently visit Louisiana compared to Tampa, Florida? Are we starting to see more severe hurricanes in a warmer climate? What changes happen to hurricanes when ocean temperatures rise? And what is the likelihood of extreme winds and deep storm surges at locations along a hurricane-prone coastline? Typically, I use statistics and maps to help answer my questions. And, as a geographer, I always make sure that the spatial element of the problem is included because, for me, differences across space are everything! I’ll be back at 12 pm ET to answer your questions, ask me anything! The AGU AMA series is conducted by the Sharing Science program. Sharing Science: By scientists, for everyone. More at sharingscience.agu.org.