News
In an unusual new study, scientists say they have detected the fingerprint of human-driven global warming on patterns of drought and moisture across the world as far back as 1900. Rising temperatures are well documented back at least that far, but this is the first time researchers have identified resulting long-term global effects on the water supplies that feed crops and cities. Among the observations, the researchers documented drying of soils across much of populous North America, central America, Eurasia and the Mediterranean. Other areas, including the Indian subcontinent, have become wetter. They say the trends will continue, with severe consequences for humans. The study appears this week in the leading journal Nature. Read More
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Got a burning question about climate change? “You Asked” is a series where Earth Institute experts tackle reader questions on science and sustainability. To submit a question, drop a comment below, message us on Instagram, or email us here.
Today’s question comes via our Earth Month Q&A on Instagram:
Why is there 21% oxygen and 0.03% carbon dioxide in the atmosphere?
Answer provided by Jason Smerdon
As student groups push for more drastic change, Columbia’s 2020 Sustainability Plan is expected to see an increased focus on carbon neutrality and include plans for greater energy efficiency and waste reduction, according to faculty involved in the initiative. Read more
Widespread summer droughts across North America are particularly damaging and costly. The last of these droughts was in 2012 and cost over an estimated $30 billion. In an effort to understand these droughts better, Hun Baek, a graduate student in the PaleoDynamics lab, has published a paper in Journal of Geophysical Research - Atmospheres exploring the oceanic and atmospheric causes of these droughts over the last ~150 years. He finds that the tropical Pacific Ocean has played an important role in forcing these droughts, but an equal contribution has come from internal atmospheric variability. He also finds a passive if ambiguous role for the Atlantic, which is in contrast to previous thinking about the influence of the Atlantic Ocean on the occurrence of widespread summer droughts in the United States. The abstract of Hun's paper is given below, while his paper can be found here.
Abstract: The contributions of oceanic and atmospheric variability to spatially widespread summer droughts in the contiguous United States (hereafter, pan‐CONUS droughts) are investigated using 16‐member ensembles of the Community Climate Model version 3 (CCM3) forced with observed sea surface temperatures (SSTs) from 1856–2012. The employed SST forcing fields are either (i) global or restricted to the (ii) tropical Pacific or (iii) tropical Atlantic to isolate the impacts of these two ocean regions on pan‐CONUS droughts. Model results show that SST forcing of pan‐CONUS droughts originates almost entirely from the tropical Pacific because of atmospheric highs from the northern Pacific to eastern North America established by La Niña conditions, with little contribution from the tropical Atlantic. Notably, in all three model configurations, internal atmospheric variability influences pan‐CONUS drought occurrence by as much or more than the ocean forcing and can alone cause pan‐CONUS droughts by establishing a dominant high centered over the U.S. montane west. Similar results are found for the Community Atmosphere Model version 5 (CAM5). Model results are compared to the observational record, which supports model‐inferred contributions to pan‐CONUS droughts from La Niñas and internal atmospheric variability. While there may be an additional association with warm Atlantic SSTs in the observational record, this association is ambiguous due to the limited number of observed pan‐CONUS droughts. The ambiguity thus opens the possibility that the observational results are limited by sampling over the twentieth century and not at odds with the suggested dominance of Pacific Ocean forcing in the model ensembles.
The 2018 Fall AGU meeting is next week and there will be many presentations from our PaleoDynamics Group, affiliated colleagues, and collaborators. Below is a chronological list of all our activities.
Kate Marvel, Ben Cook, Park Williams and Jason Smerdon: 20th-century emergence of a forced signal in global drought, Monday, 10 December 2018, 08:01-08:16, GC11B-01
Justin Mankin, Richard Seager, Jason Smerdon, Ben Cook and Park Williams, Will plants ameliorate or amplify drought risks under global warming? Monday, 10 December 2018, 11:05-11:20, GC12C-04
Sonali McDermid, Ben Cook, Justin Mankin and Park Williams, Evaluation of competing vegetation-hydroclimate interactions under elevated CO2 concentrations, Monday, 10 December 2018, 13:40-18:00, GC13G-1115
Arianna Varuolo-Clarke, Kevin Reed, and Brian Medeiros, Topographic Influences on the North American Monsoon, Monday, 10 December 2018, 17:45-18:00, A14F-08
Dan Bishop, Park Williams and Richard Seager, Fall wetting in the southeastern US driven by higher-intensity frontal precipitation, Tuesday, 11 December 2018, 13:40-18:00, A23H-2947
Richard Seager, Mark Cane, Naomi Henderson, Dong Lee and Ryan Abernathey, Recent strengthening of the tropical Pacific zonal SST gradient is a dynamically consistent response to rising greenhouse gases, Wednesday, 12 December 2018, 10:44 - 11:08, A33M-02
Toby Ault, Sloan Coats, Justin Mankin, Carlos Carrillo, Jason Smerdon, Scott St. George, Park Williams, Ben Cook, Flavio Lehner, Samantha Stevenson, and Nathan Steiger, Megadrought Risk in Low-Warming Scenarios, Wednesday, 12 December 2018, 13:40-18:00, GC33J-1502
Nathan Steiger, Jason Smerdon, Ed Cook and Ben Cook, ENSO forcing of Medieval megadroughts in the American Southwest, Wednesday, 12 December 2018, 13:55 - 14:10, PP33B-02
Park Williams, Ed Cook, Jason Smerdon, Ben Cook and Richard Seager, Twenty-first century megadrought in western North America: millennial context and anthropogenic contributions, Thursday, 13 December 2018, 09:00-09:15, H41C-05
Ben Cook, Richard Seager, Park Williams, Michael Puma, Sonali McDermid, Maxwell Kelley, Larissa Nazarenko, Climate Change Amplification of Natural Drought Variability: What if Ocean Conditions that Caused the Historic Mid-Twentieth Century North American Drought Occurred Again? Thursday, 13 December 2018, 09:30-09:45, H41C-07
Richard Seager, Tim Osborn, Yochanan Kushnir, Isla Simpson, Haibo Liu, and Jennifer Nakamura, The Hadley Cell and climate variability and change in Mediterranean-type climates, Thursday, 13 December 2018, 09:30-09:45, A41F-07
Seung Hun Baek, Nathan Steiger and Jason Smerdon, Parsing the dominant ocean influences on spatially widespread droughts in the contiguous US over the Common Era, Thursday, 13 December 2018, 09:00-09:15, PP41A-05
Richard Seager, Jennifer Nakamura, and Mingfang Ting, Mechanisms of drought onset and termination in the southern Great Plains, Thursday, 13 December 2018, 16:15-16:30, H44D-02
Bor-Ting Jong, Mingfang Ting and Richard Seager, Seasonal Evolutions of ENSO Teleconnections and Impacts on North America, Friday, 14 December 2018, 13:40-18:00, A53L-2652
Weston Anderson, Richard Seager, Walter Baethgen and Mark Cane, Climate-forced crop yield variability and synchronous crop failures, Friday, 14 December 2018, 16:30-16:45, GC54A-03
Smerdon and Ed Cook will also be convening the Climate of the Common Era session with co-coveners Kevin Anchukaitis and Kim Cobb. The two oral sessions will be on Thursday, 13 December 2018, from 8-10 and 10:20-12:20 and the poster session will be from 13:40-18:00 on the same day.
Jason Smerdon is coauthor of the newly revised Climate Change: The Science of Global Warming and Our Energy Future. The book is a succinct, non-ideological reference for anyone who wants to understand what we know (and don’t) about climate, from the basic workings of the atmosphere, oceans and solid earth through the long-term history of planetary climate, the human influence on it, and modern energy production and its implications. The book’s first edition, published in 2009, was by Edmond Mathez of the American Museum of Natural History (Smerdon wrote the student companion to that edition). The new edition, with Smerdon as coauthor, is vastly expanded and updated. Smerdon is a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory and co-director of the Earth Institute’s Undergraduate Program in Sustainable Development. We spoke with him by email about where climate, and climate science, are going. Read the rest of the story at the EI's State of the Planet Blog.
Prof. Smerdon will be giving a keynote lecture on the science of climate change as part of the Legacy Project at the County College of Morris on October 11th. The lecture will be part of a year-long focus of the Legacy Project on climate change and the intersection between science and the liberal arts.
The Smerdon PaleoDynamics Lab is happy to welcome Arianna Varuolo-Clarke as a new graduate student working with Prof. Smerdon in the Ocean and Climate Physics Division and Dr. Park Williams in the Lamont Tree-Ring Laboratory. Arianna joins us from Stony Brook University where she completed her Master's degree working with Prof. Kevin Reed on the North American Monsoon. Her PhD thesis will focus on large-scale hydroclimate variability in South America using a combination of climate reconstructions, observational data, and climate model simulations; the work is part of a large multi-institutional effort funded through an NSF PIRE award. Welcome Arianna!
The Lamont-Doherty Earth Observatory is now accepting applications for 2019 Lamont Postdoctoral Fellowships (deadline is November 12th, 2018). The Earth Institute is also accepting applications for 2019 Earth Institute Postdoctoral Fellowships. Our lab has mentored postdocs from both of these programs and we welcome your interest in pursuing research that you independently develop and pursue. Contact Prof. Jason Smerdon if you would like more information on working in our lab as a Lamont or EI postdoc.
PBS and WNET have released the video How the World Warmed as part of the Peril and Promise: The Challenge of Climate Change public media initiative; Prof. Smerdon served as an expert consultant on the video project. The teaser for the video from Peril and Promise: The earth is currently at its hottest point in recorded history and sea levels continue to rise to alarming levels around the globe- how did we get to our current climate crisis? Watch to learn “How the World Warmed” throughout history: the scientific discoveries, policy decisions, and key historical events that got us to where we are today. Can looking to the past help us understand what our future looks like in an ever-warming world?
We ignore science at our own peril. We fail to embrace and cultivate scientific enterprise at the cost of our economy, national security, environment, public health, human well-being, and international competitiveness. As a society, we choose either to make decisions based on our best efforts to define truth and reality, or to muddle through in darkness. But no matter how much a person closes their eyes and plugs their ears, the world around us is still governed by immutable natural laws that define cause and effect. Read more
An edited version of this essay was also published at the State of the Planet blog of the Earth Institute.
Early reviews are in for Climate Change: The Science of Global Warming and Our Energy Future (2nd Edition) by Ed Mathez and Jason Smerdon. The planned publication date is September 2018. Read more at the Columbia University Press webpage.
Early Reviews:
This text should have great appeal for teaching an introductory undergraduate course on climate change science as well as a broad survey for graduate students. The book is well written with concepts adequately explained. Mathez and Smerdon have done a great job at hitting many of the very important concepts for understanding past, present, and future climate change as well as what we can and should do about it. I particularly liked the “back of the envelope” sections that let students confront some quantitative thinking without getting bogged down in mathematical details. The many illustrations and beautiful photos should make the book appealing to students as well as the general public.
--Lonnie G. Thompson, Distinguished University Professor, School of Earth Sciences, The Ohio State University
Mathez and Smerdon present a concise, accurate description of the workings of our climate system that is rich with historical context, vivid graphics, and concrete examples. The beauty and wonder of our atmosphere and oceans are on full display, even as many of their mysteries are revealed for the nonspecialist. Readers will not only understand the fundamental causes and implications of climate change, but they also will understand the diverse set of tools and approaches that scientists use to study the climate system in all its complexity. This book is a treasure trove of insights for anyone with an affinity for science and an interest in the future of our planet and its inhabitants.
--Kim M. Cobb, Georgia Power Chair and ADVANCE Professor, School of Earth and Atmospheric Sciences, Georgia Institute of Technology
A superb textbook, easily one of the best currently available. Very few texts are written as thoughtfully as this one. Mathez and Smerdon hit a home run!
--Scott Mandia, cofounder and chairman of the Climate Science Legal Defense Fund, Professor of Physical Sciences at Suffolk County Community College
This book has great coverage of all the salient issues—the history of climate science, the climate science of (pre)-history, the scientists' own histories, and, most importantly, what this means going forward. The writing is clear while also comprehensive and the look and feel of the book make it a text you want to dive in to at random, confident that you'd find something interesting.
--Gavin Schmidt, climate scientist
The Climate of the Common Era has been accepted as a session at the 2018 Fall AGU Meeting. Join us for another year of broad ranging presentations relating to the climate of the last 2000 years. This year we are also specifically encouraging abstracts that are relevant to climate policy and management topics. The abstract of the session is given below and we will provide updates on the timing of the session as they become available. In the meantime, remember that the abstract submission period is now open and will close on August 1st. We look forward to seeing your abstracts in the session!
The Climate of the Common Era (PP010)
This session highlights recent work on all aspects of the climate of the Common Era using new proxy records, data syntheses, reconstruction methodologies, proxy system modeling, and paleoclimate model simulations. Contributions that combine several of these areas or that focus on developing improved quantitative estimates of uncertainty are particularly welcome. A focus of this year's session will be on the use of Common-Era data and analyses for policy and management insights. Examples include establishing a baseline for future risk assessments, conservation, and resiliency, or the characterization of past climate-society relationships as frameworks for anticipating and mitigating future impacts.
Nathan Steiger and co-authors have published the Paleo Hydrodynamics Data Assimilation product (PHYDA) in the Nature journal Scientific Data. The paper describes the development of the PHYDA and validates the reconstructions that it contains against observational data and other paleoclimatic reconstructions. The work is significant as the first global reconstruction of hydroclimate and associated dynamical variables. It uses a novel data assimilation method and the largest multiproxy database assembled to date by combining several community-complied proxy datasets. The reconstructions, code, and proxy data were all made public upon publication and are available through the links provided in the publication, through our PHYDA data page, or through the NOAA NCEI data pages.
Justin Mankin and co-authors have published a paper titled Blue Water Trade‐Offs With Vegetation in a CO2‐Enriched Climate in Geophysical Research Letters. The study uses a large ensemble of simulations to show that 42% of global vegetated land areas are projected to have “greening” in the form of additional vegetation growth at the same time as “drying” in the form of reduced soil moisture in a business‐as‐usual world. Simultaneous greening and drying is curious and suggests that future ecosystems—which could demand more water due to warmer and longer growing seasons and CO2 fertilization—siphon water that historically would have become the runoff that fills rivers and streams, termed “blue water.” The study shows that warming and changes in plant growth from CO2 creates an explicit water trade‐off in which future vegetation directly diminishes runoff relatively or absolutely for nearly half of global land areas. The results have important implications for future water availability, but also point to the crucial importance of resolving model uncertainties associated with terrestrial vegetation and its response to increasing CO2. A regional study on these effects in the western United States was also published last year.