decay

Marine carbon dioxide removal

May 23, 2024 By EarthWise Leave a Comment

About 30% of the carbon dioxide emitted by human activity is absorbed by the oceans. As a result, they are getting warmer and more acidic, and the currents that help shape global weather are shifting. To try to reduce global warming, people want to be able to store even more carbon dioxide in the oceans without the negative effects of doing so.

There are multiple efforts across the globe to achieve effective marine carbon dioxide removal. Some are based on sinking carbon-rich materials to the bottom of the sea. This is the marine equivalent of capturing CO2 from the air and storing it underground. Other efforts involve increasing the alkalinity of the ocean, which increases its ability to chemically react with carbon dioxide as well as lowers its acidity, which is desirable in many ways.

Running Tide, a U.S.-based company, has been dumping thousands of tons of wood-industry waste 190 miles off the coast of Iceland. The company has also been experimenting with dumping algae and kelp and sinking it deep below the ocean. Such materials on land either get burned or decay, in both cases releasing CO2 into the atmosphere. On the deep-sea bottom, the carbon is trapped.

Other efforts involve pumping seawater through electrodialysis filter systems to remove excess acidity or adding alkaline rocks to increase water alkalinity.

All of these efforts are a form of geoengineering, and like proposed ideas to cool the atmosphere, pose potential risks. There is no silver bullet to solve the climate crisis. It will take a combination of many solutions to address the issue of excess carbon dioxide in the atmosphere. Marine carbon dioxide removal is one of the solutions that may play a role.

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Scientists Are Trying to Coax the Ocean to Absorb More CO2

Photo, posted February 22, 2018, courtesy of Bobbie Halchishak/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic food packaging

May 9, 2024 By EarthWise Leave a Comment

Reducing the use of plastic is an important environmental goal. Plastic is made from fossil fuels and plastic pollutes the land and the oceans. It is estimated that 40% of plastic waste comes from packaging. Plastic packaging is extremely common in the supermarket and there is a growing desire to reduce its use. But it isn’t that easy.

Plastic packaging works well to slow the decay of vegetables and fruit. Its use results in less produce being tossed into the garbage, where it creates almost 60% of landfill methane emissions. In fact, food is the most common material in landfills. The average American family of four spends $1,500 a year on food that ends up uneaten and nearly half of all household food waste is fruits and vegetables.

Products like bagged salads, berries in plastic clamshells, and plastic sealed potatoes and cucumbers are popular with shoppers because they stay fresh longer. They are popular with grocers because the items don’t have to be weighed. But all these things result in plastic waste. It is a tradeoff that is difficult to make between food quality and safety vs. the environmental harm caused by plastic.

There are a variety of alternatives to plastic packaging of food that are being explored. They range from biodegradable, organic coatings that can take the place of plastic films, to cardboard and paper produce packaging.

But practically, there is yet no affordable and biodegradable plastic alternative that keeps fruits and vegetables safe and fresh. Solving the food packaging problem is not easy.

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So Much Produce Comes in Plastic. Is There a Better Way?

Photo, posted July 1, 2007, courtesy of Brian via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sustainable Plastics

January 28, 2019 By EarthWise Leave a Comment

According to the United Nations, plastic accounts for up to 90% of all the pollutants in the ocean. Conventional plastics take hundreds of years to decay, so all the plastic that gets into the oceans piles up and endangers marine life and pollutes the environment. Unfortunately, there are few comparable, environmentally friendly alternatives.

An often-proposed solution is bioplastics, which are not made from petroleum and degrade quickly. The downside of bioplastics is that growing the plants or bacteria used to make the plastic requires fertile soil and fresh water, which are scarce commodities in many places.

One such place is Israel. So, researchers there at Tel Aviv University have developed a process to make a bioplastic polymer that doesn’t require land or fresh water. The new polymer is derived from microorganisms that feed on seaweed. It is biodegradable, produces zero toxic waste and recycles into organic waste.

The polymer is called polyhydroxyalkanoate, or PHA for short. The raw material is multicellular seaweed, cultivated in the ocean. These algae are eaten by single-celled microorganisms, which also grow in salty seawater and produce a polymer that can be used to make bioplastic. PHA is already produced in commercial quantities, but it is currently made from plants that require agricultural land and fresh water. The new process would enable countries with limited fresh water, such as Israel, China and India, to switch from petroleum-based plastics to biodegradable plastics.

Plastics from fossil sources are one of the world’s biggest pollution problems. The new study shows that it is possible to produce bioplastic completely based on marine resources in an environmentally-friendly process.

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Sustainable ‘plastics’ are on the horizon

Photo, posted March 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.