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Annual maize yields in the US Corn Belt produced with the satellite-based Scalable Crop Yield Mapper (SCYM)

With today’s computing power and free satellite imagery, generating a crop yield map from satellite data is relatively easy. Knowing if that map is accurate or not, however, can be surprisingly difficult.

When ground data is sparse, researchers often evaluate yield maps by comparing regional means against government statistics. Sometimes they are able to combine this with some location-specific ground data. …


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In the United States, farmers planted over 90 million acres of soybean in 2017; in 2018, soybean planted acreage outpaced corn for the first time in decades [1]. Soybean is the United States’ most lucrative agricultural export, driven by increasing demand for animal feeds associated with rising meat consumption around the world [1].

With such an important agricultural commodity, understanding spatial and temporal patterns in yield is of widespread interest. This heterogeneity across space and time can be used to help identify yield gaps, inform farm management strategies, and guide sustainable intensification [2, 3]. …


As the world continues to warm, many agricultural regions are seeing an increased frequency and severity of conditions that lead to drought (see, e.g. here). An ongoing question has been just how damaging these climate changes will be, and how much we can lessen their impact by adapting. We know from decades of work that the ongoing climate trends are overwhelmingly negative for crops in many (but not all) systems. But there are lots of potential ways the system could adjust to become less sensitive. …


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Farmers with smartphones use the Plantix app to take photos of sick crops, and then a deep neural network diagnoses the plant with a disease or nutrient deficiency.

The Smallholder Data Gap

Smallholder farms — holdings of less than 2 hectares — produce one-third of global food consumed, employ 2 billion people, and make up 84% of the world’s farms. Yet our collective knowledge of their food production remains limited: questions like what crop types smallholders are growing and where they grow them remain unanswered, making it hard to track yield progress, study farming practices, and design agricultural policies. …


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Adobe Stock

Gaps in social science knowledge of climate change constrain the policy impact of natural science research, a Stanford team argues.

Scientists have made huge strides in understanding the physical and biological dimensions of climate change, from deciphering why climate has changed in the past to predicting how it might change in the future.

As the body of knowledge on the physical science of climate grows, a missing link is emerging: What are the economic and social consequences of changes in the climate and efforts to control emissions of greenhouse gases?

In a new paper in the journal Science, a team led by Stanford professors Charles Kolstad and Marshall Burkeargues that relatively low funding for social science research has contributed to a knowledge gap about what climate change means for human society. This knowledge gap, they argue, renders the large advances in natural science less useful than they could be for policymakers. …


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Photo: Jon Rawlinson (CC BY 2.0)

Bad weather in sub-Saharan Africa increases the spread of HIV, according to a study published in the June 2015 issue of the Economic Journal.

When the rains fail, farmers in rural areas often see their incomes fall dramatically and will try to make up for it however they can, including through sex work. Analysing data on more than 200,000 individuals across 19 African countries, the research team finds that by changing sexual behaviour, a year of very low rainfall can increase local infection rates by more than 10%.

The results have important policy implications for fighting the spread of the epidemic, as co-author Erick Gong of Middlebury College…


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Photo: Adobe Stock

As Earth’s population grows toward a projected 9 billion by 2050 and climate change puts growing pressure on the world’s agriculture, researchers are turning to technology to help safeguard the global food supply.

A research team, led by Kaiyu Guan, a postdoctoral fellow in Earth system science at Stanford’s School of Earth, Energy, & Environmental Sciences, has developed a method to estimate crop yields using satellites that can measure solar-induced fluorescence, a light emitted by growing plants. The team published its results in the journal Global Change Biology.

Scientists have used satellites to collect agricultural data since 1972, when the National Aeronautics and Space Administration (NASA) pioneered the practice of using the color — or “greenness” — of reflected sunlight to map plant cover over the entire globe. …


New research finds that without climate change mitigation, most countries will see an economic downturn by 2100.

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Image: Adobe Stock

By Laura Seaman

When thousands of scientists, economists and policymakers meet in Paris this December to negotiate an international climate treaty, one question will dominate conversations: what is the climate worth?

A new study published in the journal Nature shows that the global economy will take a harder hit from rising temperatures than previously thought, with incomes falling in most countries by the year 2100 if climate change continues unchecked. …


Children in rural Kenya are more susceptible to disease and death the farther away they live from clean drinking water, according to Stanford researchers.

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Children near a pond in Asembo, Kenya. Photo credit: Amy Pickering.

Summary:

  • An ongoing Stanford study launched in 2011 has surveyed 3,000 households in Asembo, Kenya and found that access to clean water was a key indicator for child health.
  • The average distance to a family’s nearest source of treated water was 428 meters, whereas the average distance to untreated water was 374 meters.
  • Sixty-six percent of families surveyed primarily use contaminated, untreated surface water for drinking.
  • Tests confirmed these sources were highly contaminated with E. …

About

StanfordFoodSecurity

Stanford's Center on Food Security and the Environment (FSE) leads cutting-edge research on global issues of food, hunger, poverty and the environment.

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