grassland can offer an effective solution.


A field of grass acts as a large photovoltaic cell.  Grasslands intercept incoming solar radiation using some of it to power the production of sugars from carbon taken from the air as carbon dioxide.


NATURAL FLUCTUATIONS OF CO2 EXCEEDED.
In the past two centuries, it is believed that human activities have seriously altered the global carbon cycle, most significantly in the atmosphere. Although carbon dioxide levels have changed naturally over the past several thousand years, human emissions of carbon dioxide into the atmosphere exceed natural fluctuations.  Changes in the amount of atmospheric CO2 are considerably altering weather patterns and indirectly influencing oceanic chemistry.

Grassland is one of the UK’s most valuable assets having the capacity to remove carbon from the air and sequester it into the earth.  According to the Land Use/Cover Area Survey (LUCAS), conducted in 2012, the United Kingdom has 40 per cent coverage of natural or agricultural grassland; one of the highest proportions of natural vegetation in Europe.
 
MANAGING GRAZING LIVESTOCK
Graham Harvey, in his book ‘The Carbon Fields’, describes how grasslands are essential collectors of sunlight.  One could compare a grass leaf with a small solar panel.  In a pasture, leaves are set at different angles, which make the whole canopy more efficient at gathering sunlight than a flat solar panel.  The most efficient, if not the simplest way to grow vast quantities of solar panels is for grass farmers to make full use of energy from the sun by managing grazing livestock.  American farmer Joel Salatin, from Polyface Farm in the Shenandoah Valley, Virginia, explains that all you need is some portable electric fencing and a willingness to move your livestock onto fresh pasture every day. This simple practice of rotational grazing, understood by generations of farmers before the industrial era, has the potential to produce large amounts of food.
 
LIFE CYCLE OF GRASS
Salatin is one of the pioneers of this type of farming and has an intimate knowledge of how grass grows.  He explains, ‘The important thing to know about any grass is that its growth follows a sigmoid or S curve.  The vertical axis is the height of the grass plant and the horizontal axis is time: the number of days since the paddock was last grazed.’  At first the growth is very slow but then after a few days it begins to accelerate to what is called ‘a blaze of growth’, when the grass has recovered from the first bite and rebuilt its reserves and root mass.  At around day fourteen the curve levels out and then slows down again as the grass gets ready to flower and seed.  It is now entering a period of senescence when the grass begins to get woody and becomes less palatable to the cattle. The idea is to ‘graze a pasture right at the top of the blaze of growth and never ever violate the law of the second bite’, that is to let the cattle take a second bite before the grass has had time to fully recover.
Grasslands are not composed of a single species but rather a grass "community" made up from dozens of grass, clover and herb species. When animals are allowed to graze continuously the most desirable species, such as clover, weaken and disappear from the sward giving way to bald spots and woody varieties that the cattle will not touch.  Any plant needs to keep its roots and shoots roughly in balance, so grasses kept too short by overgrazing lack the deep roots needed to bring water and minerals up from the subsoil.  Over time, overgrazed grassland deteriorates and in a dry environment will eventually turn into desert and desertification means that soil carbon is turned into atmospheric carbon.
 
HIGH PRODUCTIVITY INCREASES FERTILITY
Across the diverse grasslands on Salatin’s organic farm the animals are "pastured" in turn.  First the beef cattle graze, then as they move on, the egg laying hens are introduced in their portable hen-houses. The hens peck grubs from the grass and cowpats, spreading the dung and getting rid of parasites, while their own droppings fertilize the grass for the next batch of cattle to move in, once the grass has re-grown.  Each year, on just one hundred acres of pasture, Polyface Farm produces tons of beef and pork, thousands of chickens, turkeys and rabbits and more than four hundred thousand eggs. Despite this prodigious output, the pastures on the farm become more fertile and productive year on year.  They require no pesticides or chemical fertilizers and disprove the claim, repeated by supporters of modern intensive farming, that GM crops will be needed to feed the world’s increasing population. This productivity also means that Salatin’s pastures will remove thousands of pounds of carbon from the atmosphere each year, storing most of it underground in the form of soil humus.  

ASTONISHING DISCOVERY
Biologist Allan Savory found that for grasslands to remain healthy they require herds of hoofed animals to graze on them.  This was an astonishing discovery.  Of prime importance is that the animals must graze in large groups such as the buffalo used to do when they once roamed the huge prairies in the USA.  They did this for safety in numbers against predators, never staying in the same area for very long, and not returning for a while, thus allowing the grass to re-grow. If animals graze this way, it doesn't matter which hoofed animals are doing the grazing, wild, domestic or both, the grass begins to thrive, in fact grasses actually need regular destruction of their top leaves in order to promote root growth.
Savory’s approach enabled Salatin to turn an uneconomic farm into an operation that now supports 35 prosperous agricultural ventures.  Polyface Farm is leading an organic agricultural revival.

QUANTITIES OF ATMOSPHERIC CARBON REMOVED
Thriving grass has many impressive consequences. First of all, grass captures moisture, reduces evaporation and prevents the rain from washing away topsoil.  When the ground is covered with grass, the plant roots soak up the water and hold it. It is said that regenerating grasslands can sequester an immense amount of carbon; in fact they can remove more carbon from the air than even by the complete elimination of fossil fuels, thus effectively helping to reverse climate change . Grass also cools the atmosphere.  It prevents contamination of groundwater and surface water because it needs no artificial fertilizer and turns sunlight into abundant food.  Grasses are the foundation of entire ecosystems, allowing diverse plants and wild animals to get what they need to thrive and this thriving grassland increases biodiversity.  It creates a rich storehouse of carbon compounds in living and non-living forms such as once sustained the huge productivity of prairie grasslands.

Experts have estimated that using grazing animals, as suggested by Allan Savory, on only half of the barren or semi-barren grasslands would remove so much carbon from the air that the atmosphere would be like it was before the industrial age began.

 Savory sums up this new concept, ‘I can think of almost nothing that offers more hope for our planet, for our children, for their children, and for all of humanity’.
References: 
                      http://www.regeneratinggrassland.com/
Allan Savory   https://www.youtube.com/watch?v=vpTHi7O66pI
Wikipedia.  Carbon Cycle.
“The Carbon Fields”.      Graham Harvey. ISBN: 978-0-9560707-0-8
Joel Salatin.  
              http://www.smallfootprintfamily.com/grass-fed-beef-and-global-warming