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Biosphere integrity

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Civilization has an enormous need to utilize the biosphere, that is, the regions of the surface, atmosphere, and bodies of water of the earth occupied by living organisms.  The biosphere supplies us with food, raw materials, and increasingly, climate protection.

A study by two European universities looked at functional biosphere integrity, which is essentially the plant world’s ability to regulate the state of the Earth system.  Functional biosphere integrity faces massive human interference from consumption of resources, biodiversity loss, and climate change.

Highly detailed analysis modeled water, carbon, and nitrogen flows at a fine resolution over the entire planet and provided a detailed inventory year-by-year since the year 1600.  Each area is then assigned a status based on its tolerance limits of ecosystem change.  An area can either be a Safe Operating Space, a Zone of Increasing Risk, or a High-Risk Zone.

As the Industrial Revolution took hold, the proportion of global land area where ecosystem changes went beyond the locally defined safe zone, increased.  The current analysis shows that 60% of global land areas are now out of the safe operating space and 38% are facing high risk.

Human demand for biomass continues to grow.  The Earth system is increasingly stressed as humanity channels it into its own uses through harvested crops, residues, and timber.  At the same time, photosynthesis activity is reduced by land cultivation and sealing off land with construction.  We are not good for the biosphere.

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60 percent of the world’s land area is in a precarious state

Photo, posted September 14, 2024, courtesy of Jan Helebrant via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reindeer grazing and forest carbon

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Northern forests store a third of the world’s carbon, acting as sinks for atmospheric carbon dioxide.  Forest carbon exchange is the process whereby forests sequester carbon dioxide from the atmosphere via photosynthesis, storing it in their wood, leaves, and roots, and releasing some carbon through decomposition and respiration.  This natural cycle in forests is a critical part of the global carbon cycle and is a key factor in the mitigation of climate change.

The carbon cycle in northern forests is affected by the depth of winter snow and its duration.  It turns out that other elements of the forest ecosystem play an important role as well.  Researchers at the University of Oulu in Finland measured the impact of reindeer grazing and snow depth in Finland’s coniferous forests over a five-year period. 

There are areas in northern Finland’s forests where reindeer grazing has been excluded for decades.  In these areas, shallow snow increased carbon release.  In the same locations, deeper snow decreased carbon release.  On the other hand, in areas where reindeer grazed, carbon release remained stable regardless of changes in snow cover. 

The researchers theorize that the substantially recovered lichen cover in the ungrazed areas influences soil temperature and moisture conditions.  When combined with changing snow conditions, these factors may affect soil decomposers and, therefore, the amount of carbon released. 

The essential conclusion of this work is that multiple elements of an ecosystem, such as reindeer grazing, can buffer ecosystem functions, such as carbon exchange.    In this case, reindeer play an important role in sustaining the biodiversity of northern ecosystems. 

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Reindeer grazing can mitigate the impacts of winter climate change on forest carbon release

Photo, posted December 17, 2015, courtesy of Eco Dalla Luna via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mangrove Forests And Climate Change | Earth Wise

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Mangrove forests play a vital role in the health of our planet.  These coastal forests are the second most carbon rich ecosystems in the world.  A patch of mangrove forest the size of a soccer field can store more than 1,000 tons of carbon. It does this by capturing carbon from the air and storing it in leaves, branches, trunks, and roots.

Mangrove forests only grow at tropical and subtropical latitudes near the equator because they cannot withstand freezing temperatures.  These forests can be recognized by their dense tangle of prop roots that make the trees look like they are standing on stilts above the water.  These roots allow the trees to handle the daily rise and fall of tides.  Most mangroves get flooded at least twice a day.  The roots also slow the movement of tidal waters, which allows sediments to settle out of the water and build up on the muddy bottom.  Mangrove forests stabilize coastlines, reducing erosion from storms, currents, waves, and tides.

A new study by the University of Portsmouth in the UK looked at the effects of climate change on how carbon is stored in mangrove forests.  In mangrove ecosystems, a variety of organisms break down fallen wood.  These include fungi, beetle larvae, and termites.  Closer to the ocean, clams known as shipworms degrade organic material.

Climate change is disrupting these processes in at least two ways.  Rising sea levels are changing the way sediments build up and increased ocean acidity is dissolving the shells of marine organisms like shipworms.

Mangrove forests are crucial to mitigating climate change, and changes to the functioning of the carbon cycle of those ecosystems are a threat to their ability to perform that function.

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Study Reveals How Climate Change Can Significantly Impact Carbon-Rich Ecosystem

Photo, posted March 24, 2014, courtesy of Daniel Hartwig via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Better Way To Recycle Plastic | Earth Wise

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The current state of plastic recycling is not very effective.  Plastic recycling is only able to replace 15-20% of the fossil-fuel-derived raw material needed to produce society’s demand for plastic.

Researchers at Chalmers University in Sweden have now demonstrated how the carbon content in mixed waste could be used to replace all of the fossil raw materials in the production of new plastic.  In principle, their technology could completely eliminate the climate impact of plastic materials.

According to the researchers, there are enough carbon atoms in waste to meet the needs of all global plastic production.

The Chalmers process is based on thermochemical technology and involves heating waste to 1100-1500 degrees Fahrenheit.  The waste is thereby vaporized and when hydrogen is added, becomes a carbon-based substance that can replace the fossil-fuel building blocks of plastic.  The method does not require sorting the waste materials.  Different types of waste, such as old plastic products and even paper cups, with or without food residues, can be fed into the recycling reactors.  The researchers are now developing the techniques required to utilize their recycling technology in the same factories in which plastic products are currently being made from fossil oil or gas.

The principle of the process is inspired by the natural carbon cycle in which plants break down into carbon dioxide when they wither and die, and then photosynthesis uses carbon dioxide and solar energy to grow new plants.

Producing new plastics would no longer require petroleum or other fossil fuels as raw materials.  If the energy needed to drive the recycling reactors is taken from renewable sources, plastics could become the basis of a sustainable and circular economy.

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Pioneering recycling turns mixed waste into premium plastics with no climate impact

Photo, posted August 10, 2013, courtesy of Lisa Risager via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Carbon In The Ocean | Earth Wise

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New research from the University of Exeter in the UK reveals that the world’s oceans soak up more carbon than previously believed.  Previous estimates of the movement of carbon between the atmosphere and the oceans did not account for the temperature differences between the water’s surface and a few meters below.

The new model includes this factor and finds that there is a significantly higher flux of carbon into the oceans.

The study calculated carbon dioxide fluxes from 1992 to 2018 and found that at certain times and locations there was up to twice as much CO2 contained in the ocean as determined from previous models.

The temperature differences between the surface of the ocean and the water at a depth of a few meters is important because the amount of carbon dioxide that can be absorbed in water depends very strongly on the temperature of the water.   Anyone with a home soda maker knows this well as the devices always work much better with refrigerated water than room temperature water.

The difference in ocean carbon dioxide uptake measured from satellite data and calculated in the new modeling amounts to about 10% of global fossil fuel emissions, so it is a very significant revision.  The revised estimate for carbon dioxide uptake actually agrees much better with an independent method for calculating the amount of carbon dioxide in the oceans.  Those measurements came from a global ocean survey performed by research ships over decades.

Now that two so-called big data estimates of the ocean sink for CO2 agree pretty well, there is greater confidence that we understand this important aspect of the planet’s carbon cycle.

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Ocean carbon uptake widely underestimated

Photo, posted December 30, 2012, courtesy of Jerome Decq via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tropical Forests As Carbon Sinks | Earth Wise

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Tropical forests are an important part of the global carbon cycle because they take up and store large amounts of carbon dioxide.  Because of this, deforestation in the Amazon and other tropical forests is a major contributor to the growing CO2 levels in the atmosphere.

Therefore, climate models need to accurately take into account the ability of tropical forests to sequester carbon.  It turns out that this is not such a simple matter.  A new study by the International Institute for Applied Systems Analysis sought to determine how much detail about tropical forests is needed in order to make valid assumptions about the strength of forest carbon sinks.

They looked at the role of both biotic factors – differences between plant species that are responsible for capturing more or less carbon from the atmosphere – and abiotic factors – local environmental factors like soil properties that also influence carbon sink strength.

It is generally assumed that more diverse forest communities capture available resources more efficiently as a result of complementary characteristics and preferences of certain species to specific conditions.  Factors like soil texture and chemistry are also important.  In general, the results show that abiotic and biotic factors interact with one another to determine how much carbon can be stored by the ecosystem.

Traditional projections of the role of tropical forests in storing carbon mostly rely on remote sensing techniques that integrate over large spatial areas.  The new study shows that there can be large differences in the carbon storing ability of tropical forests and that more detailed models are needed to produce more accurate projections.

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Shedding light on how much carbon tropical forests can absorb

Photo, posted July 17, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Carbon And The Dark Ocean

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Sunlight entering the water can travel as much as 3,000 feet into the ocean depths under the right conditions, but ordinarily there is no significant light that penetrates beyond about 650 feet down.  That upper 650 feet is called the euphotic or “sunlight” zone and is home to most familiar marine life.  The “dark ocean”, everything below that depth, makes up 90% of the ocean and remarkably little is known about it.

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Carbon And Heating Soil

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Plants are a critical part of the Earth’s carbon cycle.   They take in carbon dioxide during photosynthesis.   Eventually, dead leaves, branches and other materials fall to the ground where bacteria and fungi decompose the materials and release the CO2 back into the atmosphere.  This carbon-soil feedback loop is a complicated one that is critical to the overall carbon balance because soils actually contain two to three times more carbon than the atmosphere.

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Natural Geoengineering

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The term geoengineering has started to appear in discussions about how to combat climate change.  Mostly, it is used to describe using technology to tinker with the global environment, for example, by artificially enhancing the atmosphere’s ability to reflect the sun’s rays back out into space and thereby cooling the planet.

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