Earth Wise

A look at our changing environment.

You are here: Home / Archives for accumulation

accumulation

Red mud and steel

By Leave a Comment

Most of us have never heard of red mud.  Otherwise known as bauxite residue, it is an industrial waste product generated by the most common process by which aluminum is made and the world produces 200 million tons of red mud each year.  The stuff is a significant environmental hazard being extremely alkaline and corrosive. Most of it ends up in large landfills and the costs associated with disposing of red mud are substantial.

Red mud is red because it contains large amounts of iron oxide, often as much as 60% of it.  Scientists at the Max-Planck Institute in Germany have developed a method for producing steel from red mud that is much less carbon intensive than traditional steel production and that is economically viable.

The scientists melt the red mud in an electric furnace powered in part by green hydrogen.  Running the furnace this way, even when using electricity from only partially renewable sources, results in far fewer greenhouse gas emissions as well as economic benefits.  In the furnace, liquid iron separates from the other liquid oxides and can be extracted easily.  The resultant iron is so pure that it can processed directly into steel.  The remaining metal oxides are no longer corrosive, and they solidify into a glass-like material that can have practical uses in construction.

There are 4 billion tons of red mud that have accumulated worldwide to date.  According to the researchers, their process could produce over 700 million tons of green steel from it, potentially saving 1.6 billion tons of carbon dioxide emissions. 

**********

Web Links

Green steel from toxic red mud

Photo, posted September 7, 2021, courtesy of Healthy Gulf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Better Way To Recycle Plastics | Earth Wise

By Leave a Comment

The global accumulation of plastic waste is an ever-growing problem.  At least five billion tons of the stuff has accumulated on land and sea and is even showing up in the bodies of animals and humans.  Recycling plastic instead of making even more of it seems like an essential thing to do but it has proven to be extremely challenging.

The main problem is that plastics come in many different varieties and the ways of breaking them down into a form that can be reused are very specific to each type of plastic.  Sorting plastic waste by plastic type is extremely impractical at large scale.  Certainly, most consumers can’t do it themselves.  As a result, most plastic gathered in recycling programs ends up in landfills.

New research at MIT has developed a chemical process using a catalyst based on cobalt that is very effective at breaking down a variety of plastics, including polyethylene and polypropylene, which are the two most widely produced plastics.   The MIT process breaks plastics down into propane.  Propane can be used as a fuel or as a feedstock for making many different products, including new plastics.

Plastics are hard to recycle because their long-chain molecules are very stable and difficult to break apart.  Most chemical methods for breaking their chemical bonds produce a random mix of different molecules which would somehow have to be sorted out in order to be useful for anything.

The new process uses a catalyst called a zeolite that contains cobalt nanoparticles.  The catalyst selectively breaks down various plastic polymer molecules and turns more than 80% of them into propane.

The researchers are still studying the economics and logistics of the method, but it looks quite promising.

**********

Web Links

New process could enable more efficient plastics recycling

Photo, posted April 25, 2016, courtesy of NOAA Coral Reef Ecosystem Program via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Russian Forests And Climate Mitigation | Earth Wise

By Leave a Comment

Russia is the largest country in area in the world, almost equal in size to the sum of the next two largest – Canada and the U.S.   Russia is also the world’s largest forest country, containing more than one-fifth of the world’s forests.  As a result, the country’s forests and forestry activities have enormous potential for impacting climate mitigation.

Since the dissolution of the USSR, there has been a decline in the availability of information on the state of Russia’s forests.  The Soviet Forest Inventory and Planning System compiled information until 1988.  Since then, the Russian National Forest Inventory has been the source of forest information on the national scale, and it hadn’t produced a comprehensive inventory until 2020.

The new data indicates that Russian forests have in fact accumulated a large amount of additional biomass over the intervening years.  Using the last Soviet Union report as a reference point, the new results show that the ongoing stock accumulation rate in Russian forests over the 26-year period is of the same magnitude as the net forest stock losses in tropical countries.

Thus, it is clear that Russian forests have great potential in terms of global climate mitigation as well as potential co-benefits relating to the green economy and sustainable development.   It is important to note that as the impact of climate change increases, disturbances to the Russian forests could have severe adverse effects on global climate mitigation efforts.

While much of the world’s attention is rightfully upon tropical rainforests in the Amazon and elsewhere, it is important to not ignore the largest country in the world hosting the largest land biome on the planet where even small percentage changes in the amount of forest biomass could have a major global impact.

**********

Web Links

Russian forests are crucial to global climate mitigation

Photo, posted June 6, 2015, courtesy of Raita Futo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Peatlands And Greenhouse Gas Emissions | Earth Wise

By Leave a Comment

As the world seeks to reduce the greenhouse gas emissions that have been warming the climate, most of the focus has been on the primary contributors to the problem, such as the burning of fossil fuels.  But there are many smaller contributors to greenhouse gas emissions that individually play only a minor role but collectively add up to significant amounts.  One of these is the emissions from peatlands.

Peatlands are a type of wetland that occur in almost every country on Earth, covering 3% of the global land surface.  They are terrestrial ecosystems in which waterlogged conditions prevent plant material from fully decomposing.  As a result, the production of organic matter exceeds its decomposition, which results in a net accumulation of peat.  Peatlands are, in fact, the largest natural terrestrial carbon store, storing more over 700 billion tons of carbon, more than all other types of vegetation combined.

Human activity, such as creating drainage in peatlands for agriculture and forest plantation, results in the release of over 1.6 billion tons of CO2 into the atmosphere each year. This constitutes 3% of all global greenhouse gas emissions caused by human activities.

Large numbers of people rely on peatlands for their livelihoods, so it is not reasonable for these emission-generating activities to be greatly curtailed.  But researchers at the University of Leicester in the UK analyzed the potential effects of cutting the current drainage depths in croplands and grasslands on peat in half and showed that this could reduce CO2 emissions by more than 500 million tons a year. This equates to one percent of all greenhouse gas emissions caused by human activities.

There are numerous opportunities to reduce emissions a little bit at a time.

**********

Web Links

Better peatland management could cut half a billion tonnes of carbon

Photo, posted August 17, 2013, courtesy of Joshua Mayer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Accelerating Global Glacier Loss | Earth Wise

By Leave a Comment

Glaciers represent the snows of centuries compressed over time to form flowing rivers of ice.  Glaciers always change, accumulating snow in the winter and losing ice to melting in the summer.  But in recent times, the melting has been outpacing the accumulation.

Glaciers are a sensitive indicator of climate change.  They have been melting at a high rate since the mid-20th century – regardless of altitude or latitude. But up until recently, the full extent of glacial ice loss has only been partially measured and understood.

Now, according to new research led by scientists from ETH Zurich in Switzerland and the University of Toulouse in France, nearly all the world’s glaciers are becoming thinner and losing mass.  And the changes are accelerating.  The study, which is the most comprehensive and accurate of its kind to date, is the first to include all the world’s glaciers – around 220,000 in total – excluding the Greenland and Antarctic ice sheets. The research team’s findings were recently published in the journal Nature.

Between 2000 and 2019, the world’s glaciers lost an average of more than 294 billion tons of ice per year.  Between 2000 and 2004, glaciers lost an average of about 250 billion tons of ice each year.  But between 2015 and 2019, ice mass loss jumped up to an average of approximately 328 billion tons annually.    

Glacial melt is responsible for 21% of the observed sea level rise during this two decade time period studied.

This research is just another reminder of how we need to act urgently if we want to prevent the worst-case climate change scenario from becoming a reality. 

**********

Web Links

Global glacier retreat has accelerated

Photo, posted September 17, 2015, courtesy of Richard Whitaker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Do Forests Grow Better With Our Help? | Earth Wise

By Leave a Comment

Tree planting has become a worldwide cause.  International calls to plant a trillion trees to combat climate change have led to multiple initiatives by countries around the world.  Even the current U.S. administration, with support from businesses and nonprofits has promised to plant over 800 million trees across an estimated 2.8 million acres.  Planting trees is widely seen to be a vital nature-based solution to climate change; a way of moderating its effects as the world works to reduce carbon emissions.  However, recent studies have created some pushback from that view.

The new studies are not opposed to trees.  What they have revealed is that allowing forests to grow back naturally is a better strategy than planting trees.  The new data has shown that, among other things, estimates of the rate of carbon accumulation by natural forest regrowth have on average been 32% too low and, for tropical forests, have been 53% too low.

A new study published in Nature identified 1.67 billion acres that could be set aside to allow trees to regrow.  It excludes land under cultivation or built on, along with various existing valuable ecosystems. 

Natural regrowth allows nature to select which tree species take hold and turns out to happen quite rapidly and in a widespread manner.  The great thing about natural restoration of forests is that it often requires nothing more than human inaction.  Because it requires no policy initiatives, investments, or oversight, data on its extent is rather scarce.  But the data we have reveals that wherever forests have been allowed to recover on their own, it appears to happen rapidly and with great success.

**********

Web Links

Natural Debate: Do Forests Grow Better With Our Help or Without?

Photo, posted September 5, 2015, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

How Much CO2 Can The Oceans Hold?

By Leave a Comment

The carbon dioxide that enters the atmosphere doesn’t necessarily stay there.  As part of the natural carbon cycle, much of it goes into plants, soil and, very significantly, the ocean.  In fact, the world’s oceans are a sink for human-generated carbon dioxide without which the extent of global climate change would be far worse.

Oceans takes up CO2 in two steps: first the CO2 dissolves in the surface water.  Then, the ocean’s overturning circulation distributes it.  Currents and mixing processes transport the dissolved CO2 from the surface deep into the ocean’s interior, where it accumulates over time.

A long-standing priority for climate researchers is to determine how much of the CO2 we produce is being absorbed by the oceans and, ultimately, how much can they hold?

An international team of scientists has recently provided some answers.  As reported in Science, the researchers have determined that the oceans have taken up from the atmosphere as much as 37 billion tons of human-made carbon between 1994 and 2007.  This figure corresponds to nearly a third of all the anthropogenic CO2 emitted during that time.

Furthermore, they found that the percentage of CO2 taken up by the oceans has remained relatively stable compared to the preceding 200 years even as the absolute quantity has increased.  So, evidently, the oceans’ capacity for carbon dioxide has not yet been saturated.

That’s the good news.  The bad news is that putting all that CO2 into the oceans has a steep price:  the dissolved CO2 acidifies the water.  The consequences for a wide range of marine life including coral reefs are serious and getting worse.  We need to drastically reduce carbon emissions.

**********

Web Links

Ocean sink for human-made carbon dioxide measured

Photo, posted November 5, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)