greenhouses

The green grab for land

March 27, 2025 By EarthWise Leave a Comment

Solar and wind farms are spreading rapidly around the world. Many economists believe that solar power has crossed the threshold where it is generally cheaper than other ways to make electricity and will become the dominant energy source in the next couple of decades. As a result, both solar and wind farms are gobbling up more and more land around the world. Estimates are that they will take up around 30,000 square miles by mid-century.

One concern is whether we are entering an era of trading food for energy. Land conflicts seem inevitable since solar power operates best in unshaded areas with gentle winds and moderate temperatures, which are the same conditions favored by many crops.

China is installing more solar farms than the rest of the world combined. Many of these are in the Gobi Desert, where there is no competing need for the land. But some are in eastern China, in densely populated grain-growing areas.

There are a number of strategies that reduce the impact of solar farms on land use. One approach is to put them on old industrial or brownfield sites that are otherwise unusable. Another is floatovoltaics: putting solar panels on the surface of lakes and reservoirs. And then there is agrivoltaics, where solar panels are installed above crop fields or where livestock graze between or even beneath solar arrays. China has more than 500 agrivoltaic projects that incorporate crops, livestock, aquafarming, greenhouses, and even tea plantations.

Green energy has both environmental and economic benefits to offer, but it must conserve nature and not excessively grab land needed for people, wildlife, and ecosystems.

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‘Green Grab’: Solar and Wind Boom Sparks Conflicts on Land Use

Photo, posted May 25, 2011, courtesy of Michael Mees via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The human footprint on Earth

February 6, 2025 By EarthWise Leave a Comment

The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it. But the impact of human activities on our planet continues to grow. Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Agriculture is a major part of it. Farms and pastures take up almost half of the world’s habitable land – land not covered by ice or desert. Greenhouses have recently proliferated tremendously and now cover 3.2 million acres, an area the size of Connecticut, and they even have effects on local climates.

More than half of the world’s population now lives in cities, which are expanding rapidly. Enormous cities in Asia are changing the landscape in places like Thailand and Indonesia. Apart from taking up lots of land, many of the world’s cities are immersed in clouds of air pollution that they generate.

Greenhouse gas emissions continue to grow, and temperatures continue to rise. The effects of this on the planet are increasingly evident. Seas are rising, ice is melting, glaciers shrink away, and wildfires continue to burn. The massive wildfires in and around Los Angeles have made major changes in the local landscape. Rising seas have flooded coastal wetlands and elsewhere, rivers and lakes have shrunk.

There are also human impacts visible from space that represent positive signs. Large solar arrays supply the cheapest form of energy in most parts of the world and the number and size of solar installations are at a record high. These solar installations provide some hope that global warming can be slowed.

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The Growing Human Footprint on Earth, as Seen from Space

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenhouses and the environment

July 25, 2024 By EarthWise Leave a Comment

The use of greenhouses around the world has been growing dramatically. A new satellite mapping exercise estimated the total land area covered with permanent greenhouses at 3.2 million acres, which is an area the size of Connecticut. More than half of this is in China, where the growth of greenhouses has been driven by the rapid urbanization of the country and by a more prosperous population increasingly consuming produce like tomatoes, cucumbers, peppers, and eggplants.

The intensive agricultural methods employed within greenhouses can be harmful to local environments because of overtaxing water supplies and by polluting rivers and soils with nutrients, pesticides, and plastic waste. But the effects of vast areas of plastic coverings on local temperatures can be even more dramatic, and often beneficial.

There are so many plastic and glass roofs in many areas that they are reflecting sufficient amounts of solar radiation to cool local temperatures. Greenhouse roofs increase the albedo – the reflectivity – of the land surface typically by a tenth.

All these greenhouses are just the tip of the albedo iceberg. Many farms now temporarily cover crops with reflective plastic sheets. If these coverings are included in the satellite survey, the total reflective area would be about ten times greater – roughly the size of New York State.

A study in Almeria, on the Mediterranean coast of Spain, which grows about 3 million tons of fruit and vegetables annually, determined the cooling effects of greenhouses. Weather stations amid the greenhouses showed an average cooling of 1.3 degrees Fahrenheit compared with the surrounding area.

Greenhouses are an accidental and benign form of climate engineering. The cooling provided by greenhouses is similar to the effect of white roofs in urban areas.

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Could the Global Boom in Greenhouses Help Cool the Planet?

Photo, posted September 6, 2017, courtesy of Lance Cheung / USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The largest carbon removal plant

June 11, 2024 By EarthWise Leave a Comment

Direct air capture (DAC) is process that removes carbon dioxide out of the air and stores it away where it can no longer trap heat in the atmosphere. It is intended to be a way of getting rid of the greenhouse gases that have built up in the atmosphere. In principle, it’s a great idea. In practice, it is a huge challenge.

In 2017, a company called Climeworks became the first company to take carbon dioxide out of the air and sell it as a product for use in carbonated drinks and in greenhouses. In 2021, the company opened a DAC plant called Orca in Iceland that captures CO2 and permanently stores it underground. Clients like Microsoft pay Climeworks for doing this as a way of offsetting their own emissions.

Recently, Climeworks has started operating a new plant called Mammoth – also in Iceland – that will be able to capture about 10 times more carbon dioxide than Orca. Iceland is a prime location for DAC technology because its abundant geothermal energy makes powering it cheap and environmentally friendly.

Mammoth, when fully operational, will remove about 36,000 tons of carbon dioxide a year, the largest DAC system in the world. But there is a long, long way to go. Microsoft alone emits nearly 13 million tons of carbon dioxide a year.

There are multiple DAC projects in development including several in the United States being funded by the Bipartisan Infrastructure Law. The four DAC hubs being developed under the program are each supposed to have the capacity to capture at least a million metric tons of CO2 a year.

Whether DAC can make a real difference remains to be seen.

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The world’s largest carbon removal plant is here, and bigger ones are on the way

Photo credit: Climeworks

Earth Wise is a production of WAMC Northeast Public Radio

The carbon footprint of urban agriculture

March 22, 2024 By EarthWise Leave a Comment

Urban agriculture – essentially farming within a city – has become increasingly popular worldwide. It is intended to make cities and urban food systems more sustainable. There are social and nutritional benefits to urban agriculture, but its carbon footprint has not been widely studied.

There are high-tech, energy-intensive forms of urban agriculture, such as vertical farms and rooftop greenhouses. But most urban farms are decidedly low-tech such as individual gardens managed by single farmers and community gardens managed by small groups of people.

A comprehensive international study led by the University of Michigan calculated the greenhouse gas emissions associated with the materials and activities of urban farms over their operating lives. The emissions, expressed in the quantity of carbon dioxide equivalents produced per serving of food, were then compared to those of foods raised by conventional agriculture.

On average, food produced through urban agriculture emitted six times higher amounts of CO₂per serving than conventionally grown produce.

The study went on to recommend best practices crucial to making low-tech urban agriculture more carbon-competitive with conventional agriculture. These include making use of infrastructure for more extended periods of time, making use of urban waste, and maximizing social and health benefits.

Urban agriculture offers a variety of social, nutritional, and place-based environmental benefits and has its place in future sustainable cities. It is important to implement it in ways that are most beneficial.

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Study finds that urban agriculture must be carefully planned to have climate benefits

Photo, posted July 27, 2016, courtesy of Sandra Cohen-Rose and Colin Rose via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A New Way To Remove CO2 From The Air

December 13, 2019 By EarthWise Leave a Comment

Researchers at MIT have developed a new way of removing carbon dioxide from a stream of air that could be a powerful tool in the battle against climate change. The new system can pull carbon dioxide out of almost any concentration level of the gas, even including the roughly 400 parts per million level currently found in the atmosphere.

The technique is described in a new paper in the journal Energy and Environmental Science and is based on passing air through a stack of electrochemical plates. The device is essentially a large battery that absorbs carbon dioxide from the air passing over its electrodes as it is being charged up, and then releases the gas as it is being discharged.

To use it, the device would simply alternate between charging and discharging. Fresh air or some other feed gas would be blown through the system during the charging cycle and then pure, concentrated carbon dioxide would be blown out during discharging.

The specialized battery uses electrodes coated with a compound called polyanthraquinone, which is composited with carbon nanotubes. These unique electrodes have a binary affinity to carbon dioxide, which means that they either strongly want to capture carbon dioxide or not at all, depending upon whether the device is charging or discharging.

Carbon dioxide is important in many industries such as soft drinks and greenhouse agriculture. With this device, the stuff could literally be pulled out of the air. And, of course, in power plants where exhaust gas is dumped into the air, these novel electrochemical cells could be used to prevent the emission of CO2 into the atmosphere. At the right price, this could be a game changer.

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MIT engineers develop a new way to remove carbon dioxide from air

Photo, posted August 9, 2007, courtesy of William Clifford via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Keeping Plants Plump

December 3, 2019 By EarthWise Leave a Comment

The leading cause of crop failures worldwide is drought. Ironically, the very close runner-up is flooding. Facing a changing and increasingly erratic climate, farmers need all the help they can get in protecting their crops.

Researchers at the University of California, Riverside, have created a chemical to help plants hold onto water, which could stem the tide of massive annual crop losses from drought. Details of the team’s work is described in a paper published in Science.

The chemical is called Opabactin, but is also known as “OP.” OP is gamer slang for overpowered, referring to the best character or weapon in a game.

OP mimics abscisic acid, or ABA, which is the natural hormone produced by plants in response to drought stress. ABA slows a plant’s growth, so it doesn’t consume more water than is available and doesn’t wilt. OP is 10-times stronger than ABA, which makes it a super hormone. It works fast. Within hours, there is a measurable improvement in the amount of water plants release. Because it works so quickly, OP could give farmers more flexibility in how they deal with drought. Plants can’t predict the future, but if, for example, farmers think there is a reasonable chance of drought, they could make decisions such as to apply OP to improve crop yields.

The research team is now trying to find a second chemical tool. Whereas OP slows down plant growth, the team wants to find a molecule that will accelerate it. Such a molecule could be useful in controlled environments such as indoor greenhouses. There are times when you want to speed up growth and times when you want to slow it down.

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Game changer: New chemical keeps plants plump

Photo, posted June 7, 2013, courtesy of Bayer CropScience UK via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Speed Breeding Of Crops

January 4, 2019 By EarthWise Leave a Comment

A technique pioneered by NASA for the purpose of growing plants extra-terrestrially is now being applied here on earth to fast-track improvements in a range of crops. The technique, known as speed breeding, has been adapted for use by British and Australian researchers on a scale ranging from vast greenhouses to desktop growth chambers.

Speed breeding uses enhanced LED lighting and day-long regimes of up to 22 hours to optimize photosynthesis and promote rapid growth of crops. By speeding up the breeding cycle of plants,it is possible, for example, to grow six generations of wheat in a year compared with two generations using traditional breeding methods.

With shortened breeding cycles, genetic improvements such as yield gain, disease resistance and climate resistance can be fast-tracked in crops such as wheat, barley, chickpeas, various Brassica species, oil seed rape and peas.

The ability to do this in compact desktop chambers permits cutting-edge research to be performed inexpensively before being scaled up to large greenhouses.

Crop development is an increasingly important activity and speed breeding is increasingly attractive in light of the opposition in some quarters to modern gene-editing techniques to create GMO crops. Speed breeding allows crop improvements via anon-GMO route.

The new technique is already being applied in Australia, which is experiencing one of the worst droughts on record. It is being used to rapidly cycle genetic improvements to make crops more drought resilient.

Generation time in most plant species is a major bottleneck in applied research programs and breeding. Speed breeding can greatly reduce this bottleneck, allowing scientists to respond more quickly to emerging diseases, the changing climate and increased demand for specific plant traits.

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