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Climate Extremes in a Warming World

Deepti Singh

Lamont Postdoctoral Fellow

ABOUT ME

I am a climate scientist motivated by the potential for climate studies to minimize future disaster risk to vulnerable communities around the world. Towards this goal, my research explores the physical drivers of climate extremes, and their impacts on agriculture, water availability and human health. I combine a variety of tools including observations, paleoclimate evidence, remote sensing data, and model simulations, to study extremes in the past and future climates. I am particularly interested in studying extremes such as intense rainfall, droughts, and heat waves in monsoonal climates that affect the billions of people with relatively poor adaptive capacity living in these regions.

Currently, I am a postdoctoral fellow at the Lamont-Doherty Earth Observatory of Columbia University. I received my Ph.D. in Environmental Earth System Science from Stanford University in 2015 working with Dr. Noah Diffenbaugh. My dissertation investigated trends in daily-scale extremes events in different regions, the associated physical processes, and the role of natural and anthropogenic factors in shaping their spatial and temporal characteristics. In 2015, I was recognized as a Kavli 'Frontiers of Science' Fellow by the U.S. National Academy of Sciences.

Prior to my career in earth sciences, I completed a Master's in Aeronautics and Astronautics Engineering from Purdue University while researching environmentally friendly alternatives for aviation fuels in Dr. Li Qiao's group . This interest was fueled by my passion for all things aviation-related, my research with Dr. Sudarshan Kumar at the Indian Institute of Technology Bombay for two years, and my Bachelor's in Mechanical Engineering at Vishwakarma Institute of Technology, Pune University, India.

I am passionate about building a more inclusive academic environment. At multiple institutes, I have initiated organizations aimed to improve gender diversity in STEM fields and have been involved in a number of mentoring programs targeting students from underrepresented backgrounds. I strongly believe that a more diverse community will be more effective in addressing the complex challenges facing the world today.

When I'm not actively working, I am out on adventures with my pibble Patches discovering the diverse wildlife in NYC parks including racoons and rodents, hiking both urban and natural environments, or working with the wonderful dogs at Posh Pets Rescue.

Research

Broadly, I study climate change and climate variability in different regions, with a particular focus on timescales and events that impact agriculture and human health. Following are the main themes of my research.

Extreme Events

Extreme events often have substantial socio-economic and humanitarian impacts. Future impacts from such events can be minimized through adaptation and risk management efforts informed by an improved understanding of their response to climate change. To this end, my work focuses on understanding what conditions contribute to the occurrence of extremes and why certain extreme events have changed over time. I quantify trends in different extremes over the observational record and study the associated dynamic and thermodynamic drivers of observed changes. Some of my recent work includes characterizing historical changes in rainfall extremes linked to subseasonal variability of the South Asian Summer Monsoon (Nature Climate Change); examining historical and future trends in the pattern of warm-west/cool-east extremes resembling the 2013-14 and 2014-15 winters in North America (JGR-Atmospheres); and identifying the contribution of changing circulation patterns to trends in surface extremes (Science Advances study led by Dr. Swain, and Nature study led by Dr. Horton)

Combining instrumental measurements, paleoclimate data, climate model experiments, and suitable statistical methods, my current work diagnoses the spatial structure, dynamical causes, and forcings of droughts in the last millenium that were associated with documented famines.

Influence of Natural Variability and External Climate Forcings

Over the last century, humans activities have led to increases in greenhouse gas and aerosols, and extensive land-use change. How these external forcings have shaped the characteristics of the climate in these regions is yet to be fully understood. I use process-based approaches with observations and models to understand how different levels of anthropogenic forcings alter the likelihood of climate/weather extremes and their spatio-temporal features (see JGR-Atmospheres article characterizing U.S. precipitation extremes under transient greenhouse gas increases in the 21st century). The South Asian monsoon region presents a particularly compelling region for these investigations because of the presence of high emission concentrations, rapid agricultural intensification, and the high vulnerability profile of the region. My article in Nature Climate Change discusses the influence of these forcings on the summer monsoon. I study the influence of both land and atmospheric forcings and natural variability on the monsoon circulation, its onset, and its sub-seasonal characteristics. I also examine the importance of fine-scale and large-scale processes, and teleconnection patterns in influencing seasonal and subseasonal monsoon variability.

Given the implications of single-event attribution for climate-risk management, policy, and societal perception of climate change, I am interested in developing robust approaches for quantifying the role of natural and anthropogenic factors in shaping specific and often unprecedented events. Using statistical and process-based methods, my work contributes to developing approaches to quantify the role of natural variability and anthropogenic warming on the environmental conditions contributing to specific events. Two of our attributions studies - 2013 flooding in Northern India and the 2012-present California drought, were published in the BAMS Special Issue on Explaining Extreme Events of 2013.

Climate Change Impacts

The impact of climate change spans a range of societal sectors. An improved assesment of the impacts of climate change requires an understanding of the management of current climatic factors such as rainfall timing, duration and intensity in different systems and a complete range of potential changes in these factors with increased warming. My research primarily focuses on the agricultural sector but also encompasses human health impacts. I combine ground-based surveys, yield estimates, and remote-sensing information with weather data to study a number of questions targeted around Indian agriculture. I have an on-going project targeted at learning about what climatic factors are most relevant for cropping decisions, the strategies employed by farmers to cope with rainfall extremes, the impacts of daily-scale extreme precipitation such as wet/dry spells on crop yields, and how farmers adapt to changes in seasonal and subseasonal rainfall characteristics over time. Informed by this work, I investigate future changes in the identified climate factors, including quantifying the full range of uncertainties in these estimates. Given the implications for global food-security, I also study how climate change will influence the likelihood of co-occurring shocks in different agricultural regions. I have also contributed to a study in Global Food Security on assessing the climate resilience of major cereal crops in India.

In addition to my interest in agricultural impacts, I have contributed to work on air pollution and freshwater availability. An assessment of the impacts of warming on the meteorological conditions suitable for air-stagnation events, which are conducive to trapping air-pollution is published in Nature Climate Change. Work on the potential for snowmelt to meet human water demands in major northern hemisphere basins under a warming climate is published in Environmental Research Letters.

Papers

(Please email me for copies of manuscripts not provided below)

Published

  1. Singh, D., T. Nishiie, and L. Qiao, 2011: Experimental and Kinetic Modeling Study of the Combustion of n-Decane, Jet-A, and S-8 in Laminar Premixed Flames. Combustion Science and Technology, 183, 1002–1026, doi:10.1080/00102202.2011.575420. http://dx.doi.org/10.1080/00102202.2011.575420. | PDFonline
  2. Singh, D., T. Nishiie, S. Tanvir, and L. Qiao, 2012: An experimental and kinetic study of syngas/air combustion at elevated temperatures and the effect of water addition. Fuel, 94, 448–456, doi:10.1016/j.fuel.2011.11.058. http://www.sciencedirect.com/science/article/pii/S0016236111007538. | PDFonline
  3. Singh, D., M. Tsiang, B. Rajaratnam, and N. S. Diffenbaugh, 2013: Precipitation extremes over the continental United States in a transient, high-resolution, ensemble climate model experiment. Journal of Geophysical Research: Atmospheres, 118, 7063–7086, doi:10.1002/jgrd.50543. http://dx.doi.org/10.1002/jgrd.50543.online
  4. Horton, D. E., C. B. Skinner, D. Singh, and N. S. Diffenbaugh, 2014: Occurrence and persistence of future atmospheric stagnation events. Nature Clim. Change, 4, 698–703, doi:DOI:10.1038/NCLIMATE2272. http://dx.doi.org/10.1038/nclimate2272.online
  5. Singh, D., M. Tsiang, B. Rajaratnam, and N. S. Diffenbaugh, 2014: Observed changes in extreme wet and dry spells during the South Asian summer monsoon season. Nature Clim. Change, 4, 456–461, doi:doi:10.1038/nclimate2208. http://dx.doi.org/10.1038/nclimate2208 http://10.0.4.14/nclimate2208 http://www.nature.com/nclimate/journal/v4/n6/abs/nclimate2208.html#supplementary-information. | PDFonline
  6. Singh, D., and others, 2014: Severe precipitation in Northern India in June 2013: causes, historical context, and changes in probability. [in "Explaining Extremes of 2013 from a Climate Perspective"] Bull. Amer. Meteor. Soc., 95, S58–S61. | PDF
  7. Swain, D. L., M. Tsiang, M. Haugen, D. Singh, A. Charland, B. Rajaratnam, and N. S. Diffenbaugh, 2014: 2 . THE EXTRAORDINARY CALIFORNIA DROUGHT OF 2013 / 2014 : CHARACTER , CONTEXT , AND THE ROLE OF CLIMATE CHANGE. [in "Explaining Extremes of 2013 from a Climate Perspective"]. Bull. Amer. Meteor. Soc., 95, S3–S7. | PDF
  8. Horton, D. E., N. C. Johnson, D. Singh, D. L. Swain, B. Rajaratnam, and N. S. Diffenbaugh, 2015: Contribution of changes in atmospheric circulation patterns to extreme temperature trends. Nature, 522, 465–469, doi:doi:10.1038/nature14550. http://dx.doi.org/10.1038/nature14550 http://10.0.4.14/nature14550.online
  9. Mankin, J. S., D. Viviroli, D. Singh, A. Y. Hoekstra, and N. S. Diffenbaugh, 2015: The potential for snow to supply human water demand in the present and future. Environmental Research Letters, 10, 114016, doi:doi:10.1088/1748-9326/10/11/114016. http://stacks.iop.org/1748-9326/10/i=11/a=114016. | PDFonline
  10. Singh, D., 2016: South Asian monsoon: Tug of war on rainfall changes. Nature Clim. Change, 6, 20–22, doi:doi:10.1038/nclimate2901. http://dx.doi.org/10.1038/nclimate2901 http://10.0.4.14/nclimate2901. | PDFonline
  11. Singh, D., D. L. Swain, J. S. Mankin, D. E. Horton, L. N. Thomas, B. Rajaratnam, and N. S. Diffenbaugh, 2016: Recent amplification of the North American winter temperature dipole. Journal of Geophysical Research: Atmospheres, 121, 9911–9928, doi:10.1002/2016JD025116. http://dx.doi.org/10.1002/2016JD025116. | PDFonline
  12. DeFries, R., P. Mondal, D. Singh, I. Agrawal, J. Fanzo, R. Remans, and S. Wood, 2016: Synergies and trade-offs for sustainable agriculture: Nutritional yields and climate-resilience for cereal crops in Central India. Global Food Security, doi:10.1016/j.gfs.2016.07.001. http://www.sciencedirect.com/science/article/pii/S2211912416300141. | PDFonline
  13. Swain, D. L., D. E. Horton, D. Singh, and N. S. Diffenbaugh, 2016: Trends in atmospheric patterns conducive to seasonal precipitation and temperature extremes in California. Science Advances, 2, doi:DOI:10.1126/sciadv.1501344. http://advances.sciencemag.org/content/2/4/e1501344.abstract. | PDFonline
  14. Diffenbaugh, N. S., D. Singh, and et al., 2017: Quantifying the influence of global warming on unprecedented extreme climate events. Proceedings of the National Academy of Sciences, 114, 4881–4886, doi:10.1073/pnas.1618082114.online

Academic Service

OUTREACH

I am enthusiastic about educating young and adult members of the community on topics related to the science of climate change, climate impacts, and clean energy opportunities. Through lectures, hands-on workshops and online forums, I frequently engage in educational activites. Below is a flavor of some of these activities.

Youth Science Engagement

Over the years, I have engaged in tutoring and mentoring activities with high-school students through various programs including - the college-bound program of the Boys and Girls Girls Club of the Peninsula (2010-2015), Stanford Medical Youth Program (2011), and the Lamont Secondary School Field Research program (2016). Many of the students I interacted with through these programs became first generation college students. I have also been a panelist for Early Career Researcher panel discussions for high-school groups visiting Lamont-Doherty Earth Observatory.

Workshops

I enjoy developing hands-on activities get younger students excited about science and engineering. With the Purdue Energy Club, I conducted a number of workshops for students in the Lafayette, Indiana area to educate them about clean energy technologies like solar, wind, and hydro, when I was a graduate student at Purdue (2008-2010). At Stanford, I organized workshops for middle and high-school students during Stanford Splash events. With members of the Women in Earth Sciences group at Stanford, I organized a workshop on Climate Change and Clean Energy for the Girls in Science Day in 2015 organized by the Boys and Girls Club of the Peninsula.

Public Talks and Panels

I gave two talks at the Stanford Science Circle for High-School Students in 2014 with over 50 participants from schools around the Bay Area: Generation Anthropocene: the age of human-induced changes in the Earth System and Indian Summer Monsoon and its Changing Character. With Dr. Diffenbaugh and other graduate students, I was a panelist for the Stanford Continuing Studies Program (2015) widely attended by members of the Bay Area community Earth Matters: A Matter of Degrees. With Daniel Horton, I organized a breakout session at Stanford Connecting the Dots (2014), a popular event for the Stanford and wider community: Weather going wild: Will global warming lead to more extremes? .