Rice harvests increased dramatically in India during the "Green Revolution" of the 1960s and 1970s, making the country self-sufficient in its staple food. Harvest growth has slowed since the mid-1980s, however, raising concerns that food shortages could recur in this densely populated and poor nation.
Several explanations for the slowdown have been proposed, but until now, none took into account the complex interactions of two pollution-related sources of climate change: atmospheric brown clouds (ABCs), which form from soot and other fine particles in the air (collectively termed aerosols), and the better-known problem of global warming caused by greenhouse gases such as carbon dioxide.
In the PNAS paper, Maximilian Auffhammer at UC Berkeley's College of Natural Resources, and V. "Ram" Ramanathan and Jeffrey Vincent, researchers at UC San Diego, analyze historical data on Indian rice harvests and examine the combined effects of atmospheric brown clouds and greenhouse gases on growing conditions. They find that the combined effects were negative and were greater after the mid-1980s than before, coinciding with the observed slowdown in harvest growth. They estimate that harvests would have been 20 to 25 percent higher during some years in the 1990s if the negative climate impacts had not occurred.
Previous research by an international scientific team led by Ramanathan, professor of atmospheric sciences at Scripps Institution of Oceanography, found that brown clouds have made the Indian subcontinent drier and cooler. Although this suggests the existence of a climatic tradeoff, with reductions in aerosols potentially unleashing a stronger warming trend, the current study indicates that joint reductions in the two types of pollutants would, in fact, benefit Indian rice farmers. This is because reductions in aerosols would enhance rainfall, while reductions in greenhouse gases would reduce the higher nighttime temperatures that can negatively affect the growth of the rice plant.
"Greenhouse gases and aerosols in brown clouds are known to be competing factors in global warming," said Ramanathan. "The major finding of this interdisciplinary study is that their effects on rice production are additive, which is clearly an unwelcome surprise."
Peter Timmer, senior fellow at the Center for Global Development, an independent, non-profit think tank in Washington, D.C., added that the study "links a sophisticated model of agricultural production in India to climate and pollution models, with the critical finding that 'brown cloud' pollution has already cost India millions of tons of food production."
The researchers noted that the impact of ABCs and greenhouse gases on agriculture provides another incentive for controlling air pollution in heavily polluted Asia. "Air pollution control measures in India have been motivated mainly by concern about the health of residents of the urban areas where most of the pollution is generated," said Vincent, an economist and environmental research director at the UC Institute on Global Conflict and Cooperation (IGCC). "Our study provides an additional motivation related to the economic health of poor rural areas."
Auffhammer, UC Berkeley assistant professor of agricultural and resource economics, added that "while this study focuses on India's rain-fed states, ABCs exist throughout Asia's main rice-producing countries, many of which have experienced decreasing growth rates in harvests, too. Furthering our understanding of how air pollution affects agricultural output is very important to ensure food security in the world's most populous region."
Sarah Yang | EurekAlert!
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences