
Ruth Defries
VerifiedColumbia University · American Language Program
Active 1970–2024
Research topics
- Ecology
- Environmental resource management
- Water resource management
- Geography
- Biology
- Natural resource economics
- Geology
- Business
- Environmental planning
- Environmental science
- Economics
Selected publications
Ten facts about land systems for sustainability
Proceedings of the National Academy of Sciences · 2022 · 406 citations
- Environmental resource management
- Natural resource economics
- Environmental planning
Land use is central to addressing sustainability issues, including biodiversity conservation, climate change, food security, poverty alleviation, and sustainable energy. In this paper, we synthesize knowledge accumulated in land system science, the integrated study of terrestrial social-ecological systems, into 10 hard truths that have strong, general, empirical support. These facts help to explain the challenges of achieving sustainability in land use and thus also point toward solutions. The 10 facts are as follows: 1) Meanings and values of land are socially constructed and contested; 2) land systems exhibit complex behaviors with abrupt, hard-to-predict changes; 3) irreversible changes and path dependence are common features of land systems; 4) some land uses have a small footprint but very large impacts; 5) drivers and impacts of land-use change are globally interconnected and spill over to distant locations; 6) humanity lives on a used planet where all land provides benefits to societies; 7) land-use change usually entails trade-offs between different benefits-"win-wins" are thus rare; 8) land tenure and land-use claims are often unclear, overlapping, and contested; 9) the benefits and burdens from land are unequally distributed; and 10) land users have multiple, sometimes conflicting, ideas of what social and environmental justice entails. The facts have implications for governance, but do not provide fixed answers. Instead they constitute a set of core principles which can guide scientists, policy makers, and practitioners toward meeting sustainability challenges in land use.
Groundwater depletion will reduce cropping intensity in India
Science Advances · 2021 · 236 citations
Senior authorCorresponding- Water resource management
- Environmental science
- Biology
Groundwater depletion is becoming a global threat to food security, yet the ultimate impacts of depletion on agricultural production and the efficacy of available adaptation strategies remain poorly quantified. We use high-resolution satellite and census data from India, the world's largest consumer of groundwater, to quantify the impacts of groundwater depletion on cropping intensity, a crucial driver of agricultural production. Our results suggest that, given current depletion trends, cropping intensity may decrease by 20% nationwide and by 68% in groundwater-depleted regions. Even if surface irrigation delivery is increased as a supply-side adaptation strategy, which is being widely promoted by the Indian government, cropping intensity will decrease, become more vulnerable to interannual rainfall variability, and become more spatially uneven. We find that groundwater and canal irrigation are not substitutable and that additional adaptation strategies will be necessary to maintain current levels of production in the face of groundwater depletion.
Recent grants
Nature-Based Tourism in Urbanizing Economies: The Case of India's Protected Areas
NSF · $302k · 2010–2015
Frequent coauthors
- 93 shared
Matthew C. Hansen
Humboldt-Universität zu Berlin
- 70 shared
Douglas C. Morton
- 62 shared
Miriam E. Marlier
- 54 shared
Tianjia Liu
BaiCheng Normal University
- 54 shared
John Townshend
- 51 shared
Navin Ramankutty
University of British Columbia
- 48 shared
Liana O. Anderson
- 47 shared
Loretta J. Mickley
Harvard University Press
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