Rising temperatures and human activity are increasing storm runoff and flash floods

October 22, 2018

New York, NY--October 22, 2018--Hurricanes Florence and Michael in the U.S. and Super Typhoon Mangkhut in the Philippines have shown the widespread and harmful impact of weather extremes on both ecosystems and built communities, with flash floods causing more deaths, as well as property and agriculture losses than from any other severe weather-related hazards. These losses have been increasing over the past 50 years and have exceeded $30 billion per year in the past decade. Globally, almost one billion people now live in floodplains, raising their exposure to river flooding from extreme weather events and underscoring the urgency in understanding and predicting these events.

Columbia Engineering researchers have demonstrated for the first time that runoff extremes have been dramatically increasing in response to climate and human-induced changes. Their findings, published today in Nature Communications, show a large increase in both precipitation and runoff extremes driven by both human activity and climate change. The team, led by Pierre Gentine, associate professor of earth and environmental engineering and affiliated with the Earth Institute, also found that storm runoff has a stronger response than precipitation to human-induced changes (climate change, land-use land-cover changes, etc). This suggests that projected responses of storm runoff extremes to climate and anthropogenic changes are going to increase dramatically, posing large threats to the ecosystem, affecting community resilience and infrastructure systems.

The researchers discovered that changes in storm runoff extremes in most regions of the world are in line with or higher than those of precipitation extremes. They noted that different responses of precipitation and storm runoff to temperature can be attributed not only to warming, but also to factors like land-use and land-cover changes, water and land management, and vegetation changes that have altered the underlying surface conditions and hydrological feedbacks that have, in turn, increased storm runoff.

"Our work helps explain the underlying physical mechanisms related to the intensification of precipitation and runoff extremes," Gentine said. "This will help improve flood forecasting and early-warning alerts. Our findings can help provide scientific guidance for infrastructure and ecosystem resilience planning, and could help formulate strategies for tackling climate change."

Precipitation is generated after water vapour condenses in the atmosphere, and precipitation intensity is governed by the availability of atmospheric water vapour. Because the atmosphere can hold more moisture as temperature rises, climate scientists expect to see an intensification of precipitation extremes with climate change.

Because previous studies mainly investigated the precipitation response, Gentine's team decided to examine the response of both precipitation and storm runoff extremes to naturally and anthropogenically driven changes in surface temperature and atmospheric moisture content. They performed a global scale hydrological analysis to characterize the responses and their underlying physical mechanisms. The researchers then assessed the influence of variability across decades on the scaling of runoff extremes and temperature, then systematically compared this with changes in precipitation extremes. Their observational daily runoff data came from the Global Runoff Data Centre (GRDC) datasets, and daily precipitation and near-surface air temperature data from Global Summary of the Day (GSOD) dataset.

"We were trying to find the physical mechanisms behind why precipitation and runoff extremes are increasing all over the globe," said the study's lead author Jiabo Yin, a visiting student from Wuhan University working in Gentine's group. "We know that precipitation and runoff extremes will significantly intensify in the future, and we need to modify our infrastructures accordingly. Our study establishes a framework for investigating the runoff response."

Precipitation is governed both by thermodynamics (the relationship of water vapour to temperature) and atmospheric dynamics. Gentine's team plans next to try to partition the impacts of thermodynamic and dynamics on precipitation to gain a deeper understanding about precipitation intensification. They will also focus on detecting changes due to warming versus those due to human activity in order to establish an adaptive water resources management system.
-end-
About the Study

The study is titled "Large increase in global storm runoff extremes driven by climate and anthropogenic changes."

Authors are: Jiabo Yin1,2, Pierre Gentine2,3, Sha Zhou2,3, Sylvia C. Sullivan2, Ren Wang2,4, Yao Zhang2, Shenglian Guo1

1 State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, China
2 Department of Earth and Environmental Engineering, Columbia University
3 Earth Institute, Columbia University
4 School of Geography and Planning, Sun Yat-sen University, China

The study was funded by National Key Research and Development Plan of China (Grant NO. 2016YFC0402206) and the National Natural Science Foundation of China (Grant NO. 51539009, 51579183). Jiabo and Ren are funded by China Scholarship Council.

The authors declare no competing interests.

LINKS:

Paper: http://www.nature.com/ncomms/10.1038/s41467-018-06765-2
DOI: 10.1038/s41467-018-06765-2

http://www.nature.com/ncomms/

http://engineering.columbia.edu/

https://engineering.columbia.edu/faculty/pierre-gentine

http://eee.columbia.edu/

http://www.earth.columbia.edu/

https://gentinelab.eee.columbia.edu/

Columbia Engineering

Columbia Engineering, based in New York City, is one of the top engineering schools in the U.S. and one of the oldest in the nation. Also known as The Fu Foundation School of Engineering and Applied Science, the School expands knowledge and advances technology through the pioneering research of its more than 220 faculty, while educating undergraduate and graduate students in a collaborative environment to become leaders informed by a firm foundation in engineering. The School's faculty are at the center of the University's cross-disciplinary research, contributing to the Data Science Institute, Earth Institute, Zuckerman Mind Brain Behavior Institute, Precision Medicine Initiative, and the Columbia Nano Initiative. Guided by its strategic vision, "Columbia Engineering for Humanity," the School aims to translate ideas into innovations that foster a sustainable, healthy, secure, connected, and creative humanity.

Columbia University School of Engineering and Applied Science

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.