Astronomers in Canada have detected a mysterious volley of radio waves from far outside our galaxy, according to two studies published Wednesday in Nature.

What corner of the universe these powerful waves come from and the forces that produced them remain unknown.

The so-called repeating fast radio bursts were identified during the trial run last summer of a built-for-purpose telescope running at only a fraction of its capacity.

Known by its acronym CHIME, the world’s most powerful radio telescope, spread across an area as big as a football pitch, is poised to detect many more of the enigmatic pulses now that it is fully operational.

“At the end of the year, we may have found 1,000 bursts,” said Deborah Good, a PhD student at the University of British Columbia and one of 50 scientists from five institutions involved in the research.

High energy bursts

Fast radio bursts (FRBs) flash only for a micro-instant, but can emit as much energy as the sun does in 10,000 years.

Exactly what causes these high-energy surges of long waves at the far end of the electromagnetic spectrum remains the subject of intense debate.

More than 60 bursts have been cataloged since 2007, but only one other, observed in 2012 at the Arecibo Observatory in Puerto Rico, was a repeater.

“FRBs, it seems, are likely generated in dense, turbulent regions of host galaxies,” Shriharsh Tendulkar, a corresponding author for both studies and an astronomer at McGill University, told AFP.

Cosmic convulsions created by the turbulent gas clouds that give rise to stars, or stellar explosions such a supernovae, are both possible incubators.

But consecutive radio bursts are a special case.

​No little green men

“The fact that the bursts are repeated rules out any cataclysmic models in which the source is destroyed while generating the burst,” Tendulkar added.

“An FRB emitted from a merger of two neutron stars, or a neutron star and a black hole, for example, cannot repeat.”

It is not yet clear whether the breeding grounds of repeating bursts are different from those that produce only a single radio pulse.

Significantly, the 2012 and 2018 “repeaters” have strikingly similar properties.

CHIME (Canadian Hydrogen Intensity Mapping Experiment) also spotted a dozen single burst radio waves, but with an unusual profile.

Most FRBs spotted so far have wavelengths of a few centimeters, but these had intervals of nearly a meter, opening up a whole new line of inquiry for astronomers.

Could these enigmatic radio pulses point to intelligence elsewhere in the Universe? Might they be messages in a bottle?

“It is extremely, extremely unlikely,” Tendulkar said.

“As a scientist I can’t rule it out 100 percent. But intelligent life is not on the minds of any astronomer as a source of these FRBs.”

Constructed in British Columbia, CHIME is composed of four, 100-meter long half-pipe cylinders of metal mesh, which reconstruct images of the sky by processing the radio signals recorded by more than a thousand antennas.

“This signal processing system is the largest of any telescope on Earth,” the researchers said in a communique.

The other institutions with leading roles are the University of Toronto, the National Research Council of Canada, and the Perimeter Institute.
…

Astronomers in Canada have detected a mysterious volley of radio waves from far outside our galaxy, according to two studies published Wednesday in Nature.

What corner of the universe these powerful waves come from and the forces that produced them remain unknown.

The so-called repeating fast radio bursts were identified during the trial run last summer of a built-for-purpose telescope running at only a fraction of its capacity.

Known by its acronym CHIME, the world’s most powerful radio telescope, spread across an area as big as a football pitch, is poised to detect many more of the enigmatic pulses now that it is fully operational.

“At the end of the year, we may have found 1,000 bursts,” said Deborah Good, a PhD student at the University of British Columbia and one of 50 scientists from five institutions involved in the research.

High energy bursts

Fast radio bursts (FRBs) flash only for a micro-instant, but can emit as much energy as the sun does in 10,000 years.

Exactly what causes these high-energy surges of long waves at the far end of the electromagnetic spectrum remains the subject of intense debate.

More than 60 bursts have been cataloged since 2007, but only one other, observed in 2012 at the Arecibo Observatory in Puerto Rico, was a repeater.

“FRBs, it seems, are likely generated in dense, turbulent regions of host galaxies,” Shriharsh Tendulkar, a corresponding author for both studies and an astronomer at McGill University, told AFP.

Cosmic convulsions created by the turbulent gas clouds that give rise to stars, or stellar explosions such a supernovae, are both possible incubators.

But consecutive radio bursts are a special case.

​No little green men

“The fact that the bursts are repeated rules out any cataclysmic models in which the source is destroyed while generating the burst,” Tendulkar added.

“An FRB emitted from a merger of two neutron stars, or a neutron star and a black hole, for example, cannot repeat.”

It is not yet clear whether the breeding grounds of repeating bursts are different from those that produce only a single radio pulse.

Significantly, the 2012 and 2018 “repeaters” have strikingly similar properties.

CHIME (Canadian Hydrogen Intensity Mapping Experiment) also spotted a dozen single burst radio waves, but with an unusual profile.

Most FRBs spotted so far have wavelengths of a few centimeters, but these had intervals of nearly a meter, opening up a whole new line of inquiry for astronomers.

Could these enigmatic radio pulses point to intelligence elsewhere in the Universe? Might they be messages in a bottle?

“It is extremely, extremely unlikely,” Tendulkar said.

“As a scientist I can’t rule it out 100 percent. But intelligent life is not on the minds of any astronomer as a source of these FRBs.”

Constructed in British Columbia, CHIME is composed of four, 100-meter long half-pipe cylinders of metal mesh, which reconstruct images of the sky by processing the radio signals recorded by more than a thousand antennas.

“This signal processing system is the largest of any telescope on Earth,” the researchers said in a communique.

The other institutions with leading roles are the University of Toronto, the National Research Council of Canada, and the Perimeter Institute.
…

Drivers on the U.S. East Coast may soon start paying for their climate pollution.

Nine states and the District of Columbia have announced plans to introduce a system that puts a price on the carbon dioxide produced from burning gasoline and diesel fuel.

As the federal government pulls back from taking action on climate change, the proposal is an example of how states and cities are aiming to move forward.

Details are slim at this point, but the Transportation and Climate Initiative would likely require fuel suppliers to pay for each ton of carbon dioxide that burning their products would produce. Costs would presumably be passed on to consumers.

The announcement says revenues would go toward improving transportation infrastructure and low-emissions alternatives to cars, trucks and buses.

The program could raise $1.5 billion to $6 billion per year, by one estimate.

“You can imagine, that could do a lot to modernize transportation infrastructure, improve mass transit, build out electric transportation options,” said Fatima Ahmad at the Center for Climate and Energy Solutions, based in Washington, D.C.

Reducing traffic congestion, “which is legendary in this area,” is a priority for the region’s lawmakers, she added. Those investments could create an estimated 91,000 to 125,000 new jobs.

Transportation is the largest source of greenhouse gas emissions in the United States. While electric utilities have cut production of carbon dioxide by switching from coal to natural gas and renewables, emissions from the transportation sector have been growing since 2012.

Following California

California is the only state so far that has put a price on carbon emissions from transportation fuels. The state included gas and diesel in its cap-and-trade program beginning in 2015. That program also regulates greenhouse gases from power plants and industries.

For transportation fuels, wholesalers buy the permits and pass on the cost. At the current price of about $15 per ton, the program adds about 13 cents to the cost of a gallon of gas.

The additional cost is less than the differences in pump price among gas stations in the same city, noted communications director Stanley Young at the California Air Resources Board, which administers the program.

“When you consider the few cents that the cap and trade program adds on to [the cost at the pump], it kind-of pales,” he said.

The state has raised more than $9 billion from permit sales since the program began in 2012.

Funds have paid for renewable energy and efficiency upgrades, mass transit, low-emissions vehicles, land preservation and other investments.

To help ease the burden on low-income consumers, a third of the funds are targeted to disadvantaged communities.

However, California’s program has not stopped vehicle CO2 emissions from rising. After a period of decline from 2007 to 2013, greenhouse gases from vehicles have increased every year since then.

The state is studying the impact of car sharing and autonomous vehicles on reducing emissions. Young said officials are also looking into land use planning, so people live closer to work or transit.

“We invented sprawl,” he said, “and now we’re trying to deal with it.”

Hard to change

Transportation is one of the hardest sources of greenhouse gases to tackle, experts say.

Unlike the next biggest source of carbon pollution, power plants, transportation emissions come from millions of individual vehicles, and the choices their owners and drivers make have a big impact on how much carbon dioxide they produce.

There are essentially three ways to reduce their emissions, according to David Bookbinder at the Niskanen Center, a centrist research institution: make vehicles more efficient, reduce the amount of CO2 produced per unit of energy, or raise the price of fuel.

“It’s never popular to raise the price [of fuel],” Bookbinder said. Even so, “you have to really, really, really raise the price of gasoline before it has an impact on people’s use.”

France’s “yellow vest” protests are one extreme reaction to raising fuel prices. They sparked the biggest outrage where driving is least avoidable: outside city centers and in areas lacking good public transit. And they demonstrate another risk: policies that make gas more expensive can have the biggest impact on the people who can least afford it.

One way to reduce the impact is by returning to consumers the money raised by pricing carbon. That’s the preferred approach in a proposal by a group of Republican elder statesmen. Investing in affordable public transit is another, Bookbinder says.

The members of the Transportation and Climate Initiative — Connecticut, Delaware, Maryland, Massachusetts, New Jersey, Pennsylvania, Rhode Island, Vermont, Virginia, and Washington, D.C. — will spend a year designing their individual programs.

Some states can put programs in place with agency regulations. Others will have to go through their state legislatures. That will test voters’ appetites to pay for their climate pollution.
…

Drivers on the U.S. East Coast may soon start paying for their climate pollution.

Nine states and the District of Columbia have announced plans to introduce a system that puts a price on the carbon dioxide produced from burning gasoline and diesel fuel.

As the federal government pulls back from taking action on climate change, the proposal is an example of how states and cities are aiming to move forward.

Details are slim at this point, but the Transportation and Climate Initiative would likely require fuel suppliers to pay for each ton of carbon dioxide that burning their products would produce. Costs would presumably be passed on to consumers.

The announcement says revenues would go toward improving transportation infrastructure and low-emissions alternatives to cars, trucks and buses.

The program could raise $1.5 billion to $6 billion per year, by one estimate.

“You can imagine, that could do a lot to modernize transportation infrastructure, improve mass transit, build out electric transportation options,” said Fatima Ahmad at the Center for Climate and Energy Solutions, based in Washington, D.C.

Reducing traffic congestion, “which is legendary in this area,” is a priority for the region’s lawmakers, she added. Those investments could create an estimated 91,000 to 125,000 new jobs.

Transportation is the largest source of greenhouse gas emissions in the United States. While electric utilities have cut production of carbon dioxide by switching from coal to natural gas and renewables, emissions from the transportation sector have been growing since 2012.

Following California

California is the only state so far that has put a price on carbon emissions from transportation fuels. The state included gas and diesel in its cap-and-trade program beginning in 2015. That program also regulates greenhouse gases from power plants and industries.

For transportation fuels, wholesalers buy the permits and pass on the cost. At the current price of about $15 per ton, the program adds about 13 cents to the cost of a gallon of gas.

The additional cost is less than the differences in pump price among gas stations in the same city, noted communications director Stanley Young at the California Air Resources Board, which administers the program.

“When you consider the few cents that the cap and trade program adds on to [the cost at the pump], it kind-of pales,” he said.

The state has raised more than $9 billion from permit sales since the program began in 2012.

Funds have paid for renewable energy and efficiency upgrades, mass transit, low-emissions vehicles, land preservation and other investments.

To help ease the burden on low-income consumers, a third of the funds are targeted to disadvantaged communities.

However, California’s program has not stopped vehicle CO2 emissions from rising. After a period of decline from 2007 to 2013, greenhouse gases from vehicles have increased every year since then.

The state is studying the impact of car sharing and autonomous vehicles on reducing emissions. Young said officials are also looking into land use planning, so people live closer to work or transit.

“We invented sprawl,” he said, “and now we’re trying to deal with it.”

Hard to change

Transportation is one of the hardest sources of greenhouse gases to tackle, experts say.

Unlike the next biggest source of carbon pollution, power plants, transportation emissions come from millions of individual vehicles, and the choices their owners and drivers make have a big impact on how much carbon dioxide they produce.

There are essentially three ways to reduce their emissions, according to David Bookbinder at the Niskanen Center, a centrist research institution: make vehicles more efficient, reduce the amount of CO2 produced per unit of energy, or raise the price of fuel.

“It’s never popular to raise the price [of fuel],” Bookbinder said. Even so, “you have to really, really, really raise the price of gasoline before it has an impact on people’s use.”

France’s “yellow vest” protests are one extreme reaction to raising fuel prices. They sparked the biggest outrage where driving is least avoidable: outside city centers and in areas lacking good public transit. And they demonstrate another risk: policies that make gas more expensive can have the biggest impact on the people who can least afford it.

One way to reduce the impact is by returning to consumers the money raised by pricing carbon. That’s the preferred approach in a proposal by a group of Republican elder statesmen. Investing in affordable public transit is another, Bookbinder says.

The members of the Transportation and Climate Initiative — Connecticut, Delaware, Maryland, Massachusetts, New Jersey, Pennsylvania, Rhode Island, Vermont, Virginia, and Washington, D.C. — will spend a year designing their individual programs.

Some states can put programs in place with agency regulations. Others will have to go through their state legislatures. That will test voters’ appetites to pay for their climate pollution.
…

When Bangkok’s oldest university called for ideas for a symbol to mark its centenary year, landscape architect Kotchakorn Voraakhom successfully pitched a design for a park.

It was intended not only as a welcome green space in the middle of the congested city of about 10 million people, but as a place that could also retain large amounts of water, reducing monsoon flooding around Chulalongkorn University.

Parks and “green roofs” planted with vegetation soak up rain during the annual monsoon and help dense urban centers like Bangkok adapt to climate change, Kotchakorn said.

“We need to be thinking about everything we build in the context of mitigating climate-change impact. It can’t be just about aesthetics, but also about serving a purpose,” she said.

“This was Bangkok’s first park in many years, so we had to make it count,” she told the Thomson Reuters Foundation.

Bangkok, built on the floodplains of the Chao Phraya River, is expected to be one of the urban areas hit hardest by warming temperatures.

Nearly 40 percent of Bangkok may be inundated each year as soon as 2030 due to more extreme rainfall, according to the World Bank.

The city, once a network of canals that earned it the moniker “Venice of the East,” has filled in many of those water channels for construction, and is sinking by more than 1 centimeter (0.4 inches) each year, according to climate experts.

Flooding in many parts of the city is common during the annual monsoon. The rains in 2011 brought the worst floods in decades, putting a fifth of the city under water.

“With so much construction and fewer canals, there is nowhere for the water to go,” said Kotchakorn, who heads Bangkok-based landscape architecture firm Landprocess.

“But instead of building embankments along the river or thinking of ways to get rid of the water, we should be thinking about how to live with the water – how to manage the water.”

Monkey’s cheeks

From Mumbai to Manila, unchecked sprawl has led to increased and deadly urban flooding.

A plan to build a promenade along the Chao Phraya River will worsen floods in Bangkok, environmentalists warn.

The Thai capital also has one of the lowest ratios of green space: just 3.3 square meters (35.5 sq ft) per person, compared to New York City’s 23.1 sq m and Singapore’s 66, according to the Siemens Green City Index.

A “metro forest” project in a Bangkok suburb has converted two acres (0.8 hectares) of abandoned land into a local forest with native trees, to make a start on reversing urban sprawl.

The city’s 11-acre Chulalongkorn Centenary Park designed by Kotchakorn is inclined at a three-degree angle, so that rain and floodwater flow to its lowest point, into a retention pond.

At the park’s highest end, a museum is topped by a green roof covered with native plants, which filter rainwater before it is stored in large tanks underground.

Rainwater also flows through the park’s lawn and wetlands where native vegetation filters the water, while its walkways are made of porous concrete.

The park can hold up to 1 million gallons of water that can be discharged later or used in the dry season, much like a monkey holds food in its cheeks until it needs to eat, said Kotchakorn, echoing an idea of Thailand’s revered late King Bhumibol Adulyadej to contain flooding in the city.

“No water that falls into the park is wasted,” said Kotchakorn, who is also creating a 36-acre park and green roof for Bangkok’s Thammasat University.

’Softer’ measures crucial

City officials, meanwhile, are building flood barriers and underground tunnels that can carry rainwater faster to the river.

But while infrastructure upgrades are an essential part of tackling urban flood risk, “softer” measures are also crucial, said Diane Archer, a research fellow at the Stockholm Environment Institute in Bangkok.

A key part of that is working with local people so that they can learn to take action themselves, she said.

“This includes highlighting the important role that green roofs and permeability of driveways and yards can play in reducing surface (water) runoff, with added benefits in reducing urban heat island effects,” she said.
…

When Bangkok’s oldest university called for ideas for a symbol to mark its centenary year, landscape architect Kotchakorn Voraakhom successfully pitched a design for a park.

It was intended not only as a welcome green space in the middle of the congested city of about 10 million people, but as a place that could also retain large amounts of water, reducing monsoon flooding around Chulalongkorn University.

Parks and “green roofs” planted with vegetation soak up rain during the annual monsoon and help dense urban centers like Bangkok adapt to climate change, Kotchakorn said.

“We need to be thinking about everything we build in the context of mitigating climate-change impact. It can’t be just about aesthetics, but also about serving a purpose,” she said.

“This was Bangkok’s first park in many years, so we had to make it count,” she told the Thomson Reuters Foundation.

Bangkok, built on the floodplains of the Chao Phraya River, is expected to be one of the urban areas hit hardest by warming temperatures.

Nearly 40 percent of Bangkok may be inundated each year as soon as 2030 due to more extreme rainfall, according to the World Bank.

The city, once a network of canals that earned it the moniker “Venice of the East,” has filled in many of those water channels for construction, and is sinking by more than 1 centimeter (0.4 inches) each year, according to climate experts.

Flooding in many parts of the city is common during the annual monsoon. The rains in 2011 brought the worst floods in decades, putting a fifth of the city under water.

“With so much construction and fewer canals, there is nowhere for the water to go,” said Kotchakorn, who heads Bangkok-based landscape architecture firm Landprocess.

“But instead of building embankments along the river or thinking of ways to get rid of the water, we should be thinking about how to live with the water – how to manage the water.”

Monkey’s cheeks

From Mumbai to Manila, unchecked sprawl has led to increased and deadly urban flooding.

A plan to build a promenade along the Chao Phraya River will worsen floods in Bangkok, environmentalists warn.

The Thai capital also has one of the lowest ratios of green space: just 3.3 square meters (35.5 sq ft) per person, compared to New York City’s 23.1 sq m and Singapore’s 66, according to the Siemens Green City Index.

A “metro forest” project in a Bangkok suburb has converted two acres (0.8 hectares) of abandoned land into a local forest with native trees, to make a start on reversing urban sprawl.

The city’s 11-acre Chulalongkorn Centenary Park designed by Kotchakorn is inclined at a three-degree angle, so that rain and floodwater flow to its lowest point, into a retention pond.

At the park’s highest end, a museum is topped by a green roof covered with native plants, which filter rainwater before it is stored in large tanks underground.

Rainwater also flows through the park’s lawn and wetlands where native vegetation filters the water, while its walkways are made of porous concrete.

The park can hold up to 1 million gallons of water that can be discharged later or used in the dry season, much like a monkey holds food in its cheeks until it needs to eat, said Kotchakorn, echoing an idea of Thailand’s revered late King Bhumibol Adulyadej to contain flooding in the city.

“No water that falls into the park is wasted,” said Kotchakorn, who is also creating a 36-acre park and green roof for Bangkok’s Thammasat University.

’Softer’ measures crucial

City officials, meanwhile, are building flood barriers and underground tunnels that can carry rainwater faster to the river.

But while infrastructure upgrades are an essential part of tackling urban flood risk, “softer” measures are also crucial, said Diane Archer, a research fellow at the Stockholm Environment Institute in Bangkok.

A key part of that is working with local people so that they can learn to take action themselves, she said.

“This includes highlighting the important role that green roofs and permeability of driveways and yards can play in reducing surface (water) runoff, with added benefits in reducing urban heat island effects,” she said.
…

The fight against poverty is getting help from a new direction: up.

Satellite imagery is helping researchers map areas of extreme poverty. It may help officials identify faster and more accurately when development policies and programs are working, and when they aren’t.

Eliminating extreme poverty by 2030 is the first of the 17 Sustainable Development Goals adopted by the United Nations in 2015.

Experts usually measure poverty by using census data and household surveys. But these tools are expensive, time-consuming and labor-intensive. Countries typically do them only once every several years.

On the other hand, satellites map the entire surface of the globe at high resolution every several days. The imagery is getting better and cheaper as a growing number of public and private satellite networks go into service.

What satellites see

Researchers have used the brightness of lights in nighttime photos to estimate a region’s economic activity. Others have applied machine learning to identify richer and poorer villages from satellite imagery. Another group sorted wealthy and impoverished villages and neighborhoods based on building density and vegetation cover.

A new study takes the most detailed look to date. Within a single village, it distinguished the poorest individual households from their wealthier neighbors with 62 percent accuracy.

The study focuses on Sauri, a village in rural Kenya that was part of the Millennium Villages Project, a large-scale poverty alleviation experiment. Detailed information on each household’s income and assets was collected in 2005.

In satellite images of the village, researchers measured the size of each dwelling and studied the agricultural land surrounding it.

Not surprisingly, smaller homes generally housed poorer people.

Interestingly, the researchers also found that poorer households tended to have more bare farm fields in September. In this part of Kenya, that usually means farmers are preparing the land for a second crop.

That’s a risky undertaking, said University of Edinburgh geographer and study lead author Gary Watmough, because the late-season rains fail up to half the time in this region.

“Generally, [late-season planting] is only done by the poorer households because it’s a necessity,” he said. “They either don’t have enough land or they need to have that insurance, just in case something else goes wrong.”

Satellite imagery also found poorer households’ fields were growing crops for shorter periods of time.

“When we looked back into our field data, we could see that often poorer households were actually not planting their crops in their own fields as early as others,” Watmough said. “That was because they were contracting themselves out to plant other, wealthier households’ crops first.”

The money they earned went toward buying seeds. But that meant their own crops had less time to grow.

Exciting and a little scary

The study is a big step forward, demonstrating “the potential for satellite data to distinguish between the wealth of you and your neighbor,” said World Bank economist David Newhouse, who was not involved with the research. “Which is scary, a little bit, but also somewhat exciting.”

He suggested that privacy concerns would need to be addressed before it could be scaled up.

Also, the markers of poverty found in this area will not be the same everywhere. The approach would need to be tailored to different locations. And the system’s accuracy — 62 percent — is not great on its own.

“I think the science is pretty far ahead of the practical feasibility,” Newhouse said.

It’s probably best not to rely solely on satellite data, experts say. The charity GiveDirectly used satellite images to target donations to people in villages with a high proportion of thatched roofs. These villages were considered worse off than those with more metal roofs.

But people figured it out. Some claimed to live in thatched-roof structures next to their metal-roofed houses in order to qualify for donations.

“This is really a way to use the data, but it’s also an example of how people can quickly game it,” said remote sensing expert Damien Jacques. GiveDirectly has since changed its methods.

There’s power, however, in combining satellite data and on-the-ground surveys.   

“Using the two types of data, one that is cheap to collect and very frequently available to complement traditional data that are expensive to collect and not frequent, you can get the best of the two,” Jacques said.

And remote sensing data on its own can be helpful in places surveyors can’t go, such as Yemen or North Korea, or in the wake of disasters.

But it’s not clear that changes in poverty are visible from space. That’s something Watmough and colleagues will be investigating. They have survey data from Sauri from 2005 and 2008. The next step is to look for differences in the imagery.

“Nobody has ever looked at how poverty has changed over a time period and looked at how a satellite image has changed over that same time period,” he said.
…

The fight against poverty is getting help from a new direction: up.

Satellite imagery is helping researchers map areas of extreme poverty. It may help officials identify faster and more accurately when development policies and programs are working, and when they aren’t.

Eliminating extreme poverty by 2030 is the first of the 17 Sustainable Development Goals adopted by the United Nations in 2015.

Experts usually measure poverty by using census data and household surveys. But these tools are expensive, time-consuming and labor-intensive. Countries typically do them only once every several years.

On the other hand, satellites map the entire surface of the globe at high resolution every several days. The imagery is getting better and cheaper as a growing number of public and private satellite networks go into service.

What satellites see

Researchers have used the brightness of lights in nighttime photos to estimate a region’s economic activity. Others have applied machine learning to identify richer and poorer villages from satellite imagery. Another group sorted wealthy and impoverished villages and neighborhoods based on building density and vegetation cover.

A new study takes the most detailed look to date. Within a single village, it distinguished the poorest individual households from their wealthier neighbors with 62 percent accuracy.

The study focuses on Sauri, a village in rural Kenya that was part of the Millennium Villages Project, a large-scale poverty alleviation experiment. Detailed information on each household’s income and assets was collected in 2005.

In satellite images of the village, researchers measured the size of each dwelling and studied the agricultural land surrounding it.

Not surprisingly, smaller homes generally housed poorer people.

Interestingly, the researchers also found that poorer households tended to have more bare farm fields in September. In this part of Kenya, that usually means farmers are preparing the land for a second crop.

That’s a risky undertaking, said University of Edinburgh geographer and study lead author Gary Watmough, because the late-season rains fail up to half the time in this region.

“Generally, [late-season planting] is only done by the poorer households because it’s a necessity,” he said. “They either don’t have enough land or they need to have that insurance, just in case something else goes wrong.”

Satellite imagery also found poorer households’ fields were growing crops for shorter periods of time.

“When we looked back into our field data, we could see that often poorer households were actually not planting their crops in their own fields as early as others,” Watmough said. “That was because they were contracting themselves out to plant other, wealthier households’ crops first.”

The money they earned went toward buying seeds. But that meant their own crops had less time to grow.

Exciting and a little scary

The study is a big step forward, demonstrating “the potential for satellite data to distinguish between the wealth of you and your neighbor,” said World Bank economist David Newhouse, who was not involved with the research. “Which is scary, a little bit, but also somewhat exciting.”

He suggested that privacy concerns would need to be addressed before it could be scaled up.

Also, the markers of poverty found in this area will not be the same everywhere. The approach would need to be tailored to different locations. And the system’s accuracy — 62 percent — is not great on its own.

“I think the science is pretty far ahead of the practical feasibility,” Newhouse said.

It’s probably best not to rely solely on satellite data, experts say. The charity GiveDirectly used satellite images to target donations to people in villages with a high proportion of thatched roofs. These villages were considered worse off than those with more metal roofs.

But people figured it out. Some claimed to live in thatched-roof structures next to their metal-roofed houses in order to qualify for donations.

“This is really a way to use the data, but it’s also an example of how people can quickly game it,” said remote sensing expert Damien Jacques. GiveDirectly has since changed its methods.

There’s power, however, in combining satellite data and on-the-ground surveys.   

“Using the two types of data, one that is cheap to collect and very frequently available to complement traditional data that are expensive to collect and not frequent, you can get the best of the two,” Jacques said.

And remote sensing data on its own can be helpful in places surveyors can’t go, such as Yemen or North Korea, or in the wake of disasters.

But it’s not clear that changes in poverty are visible from space. That’s something Watmough and colleagues will be investigating. They have survey data from Sauri from 2005 and 2008. The next step is to look for differences in the imagery.

“Nobody has ever looked at how poverty has changed over a time period and looked at how a satellite image has changed over that same time period,” he said.
…