Balancing phosphorus levels in crop lands is a key factor that is often overlooked in discussions of global food security, according to a paper published in the International Journal of Agricultural Resources, Governance and Ecology.
Current global issues include carbon footprints, water resources and climate change. However, the non-renewable element phosphorus for plant growth is often overlooked in the global context.
Biologist John Lott of McMaster University, in Hamilton, Ontario, Canada, and colleagues there and at the University of Sydney, Australia, point out that when food scarcity increases, instability in society increases. Given that the majority of the food we eat is from cereals and legumes, the phosphorus cycle is a critical element of food security. Phosphorus is essential for crop plant growth, but soils become depleted as it is removed from the land when the grain and seeds are harvested.
The researchers have analysed nine years of data on total dry cereal grain and total dry legume seed production, production of barley, maize, rice, soybean and wheat grains/seeds, yields, area farmed, the tonnage of phosphorus and phytic acid removed in these crops and the elemental phosphorus applied as mineral fertilizers to all plant crops.
The world estimate of the elemental P removed with the dry seed/grain and fleshy fruit crops that contain seeds is in the range of 56-71% of the elemental phosphorus applied as mineral fertilizer for all purposes worldwide. Depending on the soil type, considerable amounts of phosphorus may become unusable by plants, the team explains.
An analysis of the phosphorus data by the team reveals several significant imbalances in the agricultural cycling of phosphorus that could seriously affect global food security. For instance, Asia consumes significantly more mineral phosphorus fertilizer in proportion to crop production than any other region, which could represent a potential environmental, economic and social problem for that part of the world.
"This is a particularly relevant and important topic in the light of the increasing global population since high quality P reserves are diminishing and the cost of fertilizers are escalating rapidly with few options available to increase fertilizer phosphorus use efficiency," the team says.
There are various approaches to improving the position of phosphorus in food production and security, Lott and colleagues suggest. More effort must be made to combine all possible factors to increase the supply of our most important cereal and legume grain/seed crops in an efficient and environmentally sustainable way, they explain. That means optimising the use of phosphorus fertilizers, using selective breeding and genetic modification to produce crops that require less phosphorus depending on whether they are destined for animal feed or human consumption. Most of all, improving agricultural and governance practices can all play important roles in improving food security, in general.
Story Source:
Adapted from materials provided by Inderscience Publishers, via EurekAlert!, a service of AAAS.
Journal Reference:
1. John Lott et al. A review of the phosphorus content of dry cereal and legume crops of the world. Int. J. Ag
Showing posts with label Carbon Foot print. Show all posts
Showing posts with label Carbon Foot print. Show all posts
Sunday, April 25, 2010
Saturday, September 5, 2009
The Global Carbon Cycle
The global carbon cycle can be divided into two categories: the geological, which operates over large time scales (millions of years), and the biological - physical, which operates at shorter time scales (days to thousands of years) and as humans we meddle with both categories.
The global carbon cycle refers to the movements of carbon, as it exchanges between reservoirs (sinks), and occurs because of various chemical, physical, geological, and biological processes. The ocean contains the largest active pool of carbon near the surface of the Earth, but the deep ocean part of this pool does not rapidly exchange with the atmosphere. Below in the diagram, you can get some idea where and how carbon is stored in the whole Earth system. The global carbon cycle is usually thought to have four major carbon sinks interconnected by pathways of exchange. These sinks are;
* the atmosphere,
* the terrestrial biosphere (which usually includes freshwater systems and non-living organic material, such as soil carbon),
* the oceans (which includes dissolved inorganic carbon and living and non-living marine biota),
* and the sediments (which includes fossil fuels ).
Carbon exists in the Earth's atmosphere primarily as the gas carbon dioxide (CO2). Although it is a very small part of the atmosphere overall (approximately 0.04% and rising fast), it plays an important role in supporting life. Other gases containing carbon in the atmosphere are methane and chlorofluorocarbons (the latter is one we introduced and are still adding to). These are all greenhouse gases whose concentration in the atmosphere are increasing, and contributing to the rising average global surface temperature.
Global Carbon Cycle - Sinks and Storage
Carbon is taken up from Earth's system in several ways:
1. When the sun is shining, plants perform photosynthesis to convert carbon dioxide into carbohydrates, releasing oxygen in the process. Deforestation and land clearing pose serious problems to the carbon cycle, and obliterating this sink means more carbon is forced into the atmosphere.
2. At the surface of the oceans towards the poles, seawater becomes cooler and CO2 is more soluble. Cold ocean temperatures favour the uptake of carbon dioxide from the atmosphere whereas warm temperatures can cause the ocean surface to release carbon dioxide. With seas warming this means CO2 is not so easily absorbed, and remains in the atmosphere. This is coupled to the ocean's thermohaline circulation which transports dense surface water into the ocean's interior. During times when photosynthesis exceeded respiration, organic matter slowly built up over millions of years to form coal and oil deposits. All of these biologically mediated processes represent a removal of carbon dioxide from the atmosphere and storage of carbon in geologic sediments.
3. In upper ocean areas of high productivity, organisms form tissue containing carbon, and some also form carbonate shells or other hard body parts. Apart from trees in forests, phytoplankton in the Earth's oceans are very important organisms that soak up carbon. The seas contain around 36000 gigatonnes of carbon, and again and in warmer seas, organisms cannot produce carbonate shells at the same rate, and increasingly acidic seas dissolve shells, or make it difficult to create shelly material. This means of course that carbon dioxide is not being taken up as quickly through this process and more carbon remains in the atmosphere, propelling global warming.
4. As shelled organisms die, bits and pieces of the shells fall to the bottom of the oceans and accumulate as sediments. Only small amounts of residual carbon from plankton settle out to the ocean bottom but over long periods of time these represent a significant removal of carbon from the atmosphere.
Global Carbon Cycle - Sources
Carbon can be released back into the system in many different ways:
1. Through the respiration performed by plants and animals.
2. Through the decay of animal and plant matter. Fungi and bacteria break down the carbon compounds in dead animals and plants and convert the carbon to carbon dioxide if oxygen is present, or methane if not. The melting permafrost is releasing large amounts of methane, which contributes to global warming at a rate 21 more times than carbon dioxide.
3. Through combustion of biomass which oxidizes the carbon it contains, producing carbon dioxide (as well as other things, like smoke). Burning fossil fuels such as coal, petroleum products, and natural gas releases millions of tonnes of carbon that has been stored in the geosphere for millions of years. Fires also consume biomass and organic matter to produce carbon dioxide (along with methane, carbon monoxide, smoke), and the vegetation that is killed but not consumed by the fire decomposes over time adding further carbon dioxide to the atmosphere. Wildfires and forest fires are likely to increase as land masses dry out with higher rates of evaporation.
4. Production of cement. A component, lime, is produced by heating limestone, which produces a substantial amount of carbon dioxide, and impacting upon the global carbon cycle.
5. At the surface of the oceans where the water becomes warmer, dissolved carbon dioxide is released back into the atmosphere.
6. Volcanic eruptions and metamorphism are part of the global carbon cycle and release gases into the atmosphere. These gases include water vapour, carbon dioxide and sulphur dioxide. Find out how volcanic gases are measured here.
Latest Trends and Cause for Alarm!
There has been a decline in the efficiency of natural land and ocean sinks which soak up carbon dioxide (CO2) emitted to the atmosphere by human activities (anthropogenic) , according to findings published in late Oct 2007, in the Proceedings of the National Academy of Sciences of the US (PNAS).
The swift increase in atmospheric CO2 is due to faster economic growth coupled with a halt in carbon intensity reductions, in addition to natural sinks removing a smaller proportion of emissions from the air. Carbon intensity is the amount of carbon emitted to produce one dollar of global wealth.
The study’s lead author, Dr Pep Canadell, executive director of the Global Carbon Project, explained “Fifty years ago, for every tonne of CO2 emitted, 600kg were removed by natural sinks. In 2006 only 550kg were removed per tonne and that amount is falling.”
“In addition to the growth of global population and wealth, we now know that significant contributions to the growth of atmospheric CO2 arise from the slow down of natural sinks and the halt to improvements in carbon intensity.” The rise in growth in atmospheric CO2 is generating climate forcings that are bigger and sooner than expected. By altering the global energy balance, these mechanisms "force" the climate to change.
Taking Action
We already possess the scientific, technical, and industrial know how to solve the carbon and climate problem for the next half-century. A concept known as "carbon wedges" proposes to limit the human contribution to the global carbon cycle, in an effort to reduce global warming. Adoption of the wedge concept is essential if we are going to curb our extraordinary abuse of fossil based fuels.
The global carbon cycle refers to the movements of carbon, as it exchanges between reservoirs (sinks), and occurs because of various chemical, physical, geological, and biological processes. The ocean contains the largest active pool of carbon near the surface of the Earth, but the deep ocean part of this pool does not rapidly exchange with the atmosphere. Below in the diagram, you can get some idea where and how carbon is stored in the whole Earth system. The global carbon cycle is usually thought to have four major carbon sinks interconnected by pathways of exchange. These sinks are;
* the atmosphere,
* the terrestrial biosphere (which usually includes freshwater systems and non-living organic material, such as soil carbon),
* the oceans (which includes dissolved inorganic carbon and living and non-living marine biota),
* and the sediments (which includes fossil fuels ).
Carbon exists in the Earth's atmosphere primarily as the gas carbon dioxide (CO2). Although it is a very small part of the atmosphere overall (approximately 0.04% and rising fast), it plays an important role in supporting life. Other gases containing carbon in the atmosphere are methane and chlorofluorocarbons (the latter is one we introduced and are still adding to). These are all greenhouse gases whose concentration in the atmosphere are increasing, and contributing to the rising average global surface temperature.
Global Carbon Cycle - Sinks and Storage
Carbon is taken up from Earth's system in several ways:
1. When the sun is shining, plants perform photosynthesis to convert carbon dioxide into carbohydrates, releasing oxygen in the process. Deforestation and land clearing pose serious problems to the carbon cycle, and obliterating this sink means more carbon is forced into the atmosphere.
2. At the surface of the oceans towards the poles, seawater becomes cooler and CO2 is more soluble. Cold ocean temperatures favour the uptake of carbon dioxide from the atmosphere whereas warm temperatures can cause the ocean surface to release carbon dioxide. With seas warming this means CO2 is not so easily absorbed, and remains in the atmosphere. This is coupled to the ocean's thermohaline circulation which transports dense surface water into the ocean's interior. During times when photosynthesis exceeded respiration, organic matter slowly built up over millions of years to form coal and oil deposits. All of these biologically mediated processes represent a removal of carbon dioxide from the atmosphere and storage of carbon in geologic sediments.
3. In upper ocean areas of high productivity, organisms form tissue containing carbon, and some also form carbonate shells or other hard body parts. Apart from trees in forests, phytoplankton in the Earth's oceans are very important organisms that soak up carbon. The seas contain around 36000 gigatonnes of carbon, and again and in warmer seas, organisms cannot produce carbonate shells at the same rate, and increasingly acidic seas dissolve shells, or make it difficult to create shelly material. This means of course that carbon dioxide is not being taken up as quickly through this process and more carbon remains in the atmosphere, propelling global warming.
4. As shelled organisms die, bits and pieces of the shells fall to the bottom of the oceans and accumulate as sediments. Only small amounts of residual carbon from plankton settle out to the ocean bottom but over long periods of time these represent a significant removal of carbon from the atmosphere.
Global Carbon Cycle - Sources
Carbon can be released back into the system in many different ways:
1. Through the respiration performed by plants and animals.
2. Through the decay of animal and plant matter. Fungi and bacteria break down the carbon compounds in dead animals and plants and convert the carbon to carbon dioxide if oxygen is present, or methane if not. The melting permafrost is releasing large amounts of methane, which contributes to global warming at a rate 21 more times than carbon dioxide.
3. Through combustion of biomass which oxidizes the carbon it contains, producing carbon dioxide (as well as other things, like smoke). Burning fossil fuels such as coal, petroleum products, and natural gas releases millions of tonnes of carbon that has been stored in the geosphere for millions of years. Fires also consume biomass and organic matter to produce carbon dioxide (along with methane, carbon monoxide, smoke), and the vegetation that is killed but not consumed by the fire decomposes over time adding further carbon dioxide to the atmosphere. Wildfires and forest fires are likely to increase as land masses dry out with higher rates of evaporation.
4. Production of cement. A component, lime, is produced by heating limestone, which produces a substantial amount of carbon dioxide, and impacting upon the global carbon cycle.
5. At the surface of the oceans where the water becomes warmer, dissolved carbon dioxide is released back into the atmosphere.
6. Volcanic eruptions and metamorphism are part of the global carbon cycle and release gases into the atmosphere. These gases include water vapour, carbon dioxide and sulphur dioxide. Find out how volcanic gases are measured here.
Latest Trends and Cause for Alarm!
There has been a decline in the efficiency of natural land and ocean sinks which soak up carbon dioxide (CO2) emitted to the atmosphere by human activities (anthropogenic) , according to findings published in late Oct 2007, in the Proceedings of the National Academy of Sciences of the US (PNAS).
The swift increase in atmospheric CO2 is due to faster economic growth coupled with a halt in carbon intensity reductions, in addition to natural sinks removing a smaller proportion of emissions from the air. Carbon intensity is the amount of carbon emitted to produce one dollar of global wealth.
The study’s lead author, Dr Pep Canadell, executive director of the Global Carbon Project, explained “Fifty years ago, for every tonne of CO2 emitted, 600kg were removed by natural sinks. In 2006 only 550kg were removed per tonne and that amount is falling.”
“In addition to the growth of global population and wealth, we now know that significant contributions to the growth of atmospheric CO2 arise from the slow down of natural sinks and the halt to improvements in carbon intensity.” The rise in growth in atmospheric CO2 is generating climate forcings that are bigger and sooner than expected. By altering the global energy balance, these mechanisms "force" the climate to change.
Taking Action
We already possess the scientific, technical, and industrial know how to solve the carbon and climate problem for the next half-century. A concept known as "carbon wedges" proposes to limit the human contribution to the global carbon cycle, in an effort to reduce global warming. Adoption of the wedge concept is essential if we are going to curb our extraordinary abuse of fossil based fuels.
Wednesday, September 2, 2009
Greenhouse Gas
We hear a lot about Greenhouse gas, but what is this? Why do these gases pose such a problem? Our atmosphere is a layer surrounding the earth held in place by gravity and primarily made up of Nitrogen (78%), Oxygen (21%), with water vapour and various gases making up the remainder.
It is on the 'remainder' that we will focus as it is the concentrations of these trace gases that cause the greenhouse gas problem. The trace gases are made up of Argon, Carbon Dioxide, Neon, Helium, Methane, Hydrogen, Nitrous Oxide and Ozone. (Follow the link to read more about the Ozone Hole) Human activities result in emissions of four principal greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and the halocarbons (a group of gases containing fluorine, chlorine and bromine). All these gases have what is known as - Global Warming Potential , or GWP with some much higher than others.
Scientists now realise that the proportion of these gases has increased significantly over a few hundred years. The real increase began around the time of the Industrial Revolution. This is when we began to burn fossil fuels (coal) in large quantities to power our steam engines for industry, generate electricity, and heat our homes.
You can see from the graph below that carbon dioxide, nitrous oxide and methane have all increased significantly since the 1800s. Today the use of fossil fuel for power and electricity is thousands of times more than what it was in the 1800s.
The Greenhouse Blanket
Ok… You see how these gases have increased proportionally in our atmosphere, but perhaps you are thinking, so what?
To explain why these gases are termed greenhouse gases, we need to understand that during the day the earth absorbs heat from the sun, although much of this is radiated back out into space. The atmosphere surrounding our earth contains these gases, and acts like a blanket keeping some of the heat in. If there weren’t an atmospheric ‘blanket’ life may be impossible on Earth because everything would freeze at night, like some of the other planets or our moon.
This is where it gets a bit frightening! The fossil fuels we are burning in ever-increasing amounts contribute to higher concentrations of carbon dioxide, methane and nitrous dioxide (although oil reserves are running out ). These gases are called greenhouse gases because they effectively make the blanket around our globe thicker, trapping more heat and turning the globe into a green house.
The Big Issue
The problem with humans contributing so much carbon dioxide is that Earth's natural system is overwhelmed and can't keep up with the rate of our CO2 release. The natural carbon cycle is disrupted and Earth's carbon 'sinks' or places that carbon can be safely absorbed are either diminishing or saturated.
We have coined the terms 'Global Warming' and 'Climate Change', to describe what is happening. Global economic growth is driving higher carbon dioxide emissions and we really must manage the tremendous amounts of carbon dioxide we are emitting.
The Carbon Cycle section explains in more detail what the carbon 'sinks' or reservoirs are. The concept of sinks is extremely important in understanding the nature of this problem.
Making a serious dent in our emissions will require a number of measures such as renewable energy targets, measures to support energy efficiency, addressing energy market failures through feed-in tariffs and the continued support for commercialisation of clean energy technologies.
Atmospheric pollution is also behind the idea of Global Dimming(which is not truly global). In this theory, the particulates emitted when burning fossil fuels could be shielding us from the full impact of global warming.
For a quick one page summary on the Facts and Impacts of Climate Change go here
Greenhouse Gas Increasing
According to the US National Oceanic and Atmospheric Administration (NOAA), the amount of carbon dioxide (CO2) in the atmosphere increased by 19 billion tonnes in 2007. This is a rise of 0.6 per cent, lifting the concentration of the main greenhouse gas to 385 parts per million (ppm).
The measurements showed that levels of the second most abundant greenhouse gas, methane, jumped after being steady in recent years.
The rise in carbon dioxide from 280 ppm, along with increases in the other greenhouse gases, since the start of the Industrial Revolution is warming the planet changing our climate change beyond the natural cyclical variability.
The 2007 rise in global carbon dioxide is the third highest annual increase since atmospheric measurements began in 1958 and 20 per cent higher than the average of recent years.
The 19 billion tonne increase reflects an imbalance that has occurred in the planet’s carbon balance the net impact on atmospheric carbon dioxide from human and natural emissions on the one hand outweighing absorption from the air by oceans, vegetation and the soil. Since 2000, CO2 concentrations have been rising at 2 ppm every year compared to less than 1 ppm per year up to the 1960s.
Carbon Footprints
We all have a 'carbon footprint', which is a measure of the amount of carbon dioxide or CO2 emitted through the combustion of fossil fuels. This is directly related to the amount of natural resources consumed, and is increasingly used or referred to as a measure of environmental impact. The United States is certainly the biggest emitter, but with economies like China and India booming, the problem is set to expand exponentially. Below is a map showing tons of carbon dioxide emmited per country. How much carbon dioxide does your country contribute?
Global weather patterns are changing and greenhouse gas issues are affecting people... right now. You can make a difference, become informed, speak out, lobby politicians and get involved at a community level.
It is on the 'remainder' that we will focus as it is the concentrations of these trace gases that cause the greenhouse gas problem. The trace gases are made up of Argon, Carbon Dioxide, Neon, Helium, Methane, Hydrogen, Nitrous Oxide and Ozone. (Follow the link to read more about the Ozone Hole) Human activities result in emissions of four principal greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and the halocarbons (a group of gases containing fluorine, chlorine and bromine). All these gases have what is known as - Global Warming Potential , or GWP with some much higher than others.
Scientists now realise that the proportion of these gases has increased significantly over a few hundred years. The real increase began around the time of the Industrial Revolution. This is when we began to burn fossil fuels (coal) in large quantities to power our steam engines for industry, generate electricity, and heat our homes.
You can see from the graph below that carbon dioxide, nitrous oxide and methane have all increased significantly since the 1800s. Today the use of fossil fuel for power and electricity is thousands of times more than what it was in the 1800s.
The Greenhouse Blanket
Ok… You see how these gases have increased proportionally in our atmosphere, but perhaps you are thinking, so what?
To explain why these gases are termed greenhouse gases, we need to understand that during the day the earth absorbs heat from the sun, although much of this is radiated back out into space. The atmosphere surrounding our earth contains these gases, and acts like a blanket keeping some of the heat in. If there weren’t an atmospheric ‘blanket’ life may be impossible on Earth because everything would freeze at night, like some of the other planets or our moon.
This is where it gets a bit frightening! The fossil fuels we are burning in ever-increasing amounts contribute to higher concentrations of carbon dioxide, methane and nitrous dioxide (although oil reserves are running out ). These gases are called greenhouse gases because they effectively make the blanket around our globe thicker, trapping more heat and turning the globe into a green house.
The Big Issue
The problem with humans contributing so much carbon dioxide is that Earth's natural system is overwhelmed and can't keep up with the rate of our CO2 release. The natural carbon cycle is disrupted and Earth's carbon 'sinks' or places that carbon can be safely absorbed are either diminishing or saturated.
We have coined the terms 'Global Warming' and 'Climate Change', to describe what is happening. Global economic growth is driving higher carbon dioxide emissions and we really must manage the tremendous amounts of carbon dioxide we are emitting.
The Carbon Cycle section explains in more detail what the carbon 'sinks' or reservoirs are. The concept of sinks is extremely important in understanding the nature of this problem.
Making a serious dent in our emissions will require a number of measures such as renewable energy targets, measures to support energy efficiency, addressing energy market failures through feed-in tariffs and the continued support for commercialisation of clean energy technologies.
Atmospheric pollution is also behind the idea of Global Dimming(which is not truly global). In this theory, the particulates emitted when burning fossil fuels could be shielding us from the full impact of global warming.
For a quick one page summary on the Facts and Impacts of Climate Change go here
Greenhouse Gas Increasing
According to the US National Oceanic and Atmospheric Administration (NOAA), the amount of carbon dioxide (CO2) in the atmosphere increased by 19 billion tonnes in 2007. This is a rise of 0.6 per cent, lifting the concentration of the main greenhouse gas to 385 parts per million (ppm).
The measurements showed that levels of the second most abundant greenhouse gas, methane, jumped after being steady in recent years.
The rise in carbon dioxide from 280 ppm, along with increases in the other greenhouse gases, since the start of the Industrial Revolution is warming the planet changing our climate change beyond the natural cyclical variability.
The 2007 rise in global carbon dioxide is the third highest annual increase since atmospheric measurements began in 1958 and 20 per cent higher than the average of recent years.
The 19 billion tonne increase reflects an imbalance that has occurred in the planet’s carbon balance the net impact on atmospheric carbon dioxide from human and natural emissions on the one hand outweighing absorption from the air by oceans, vegetation and the soil. Since 2000, CO2 concentrations have been rising at 2 ppm every year compared to less than 1 ppm per year up to the 1960s.
Carbon Footprints
We all have a 'carbon footprint', which is a measure of the amount of carbon dioxide or CO2 emitted through the combustion of fossil fuels. This is directly related to the amount of natural resources consumed, and is increasingly used or referred to as a measure of environmental impact. The United States is certainly the biggest emitter, but with economies like China and India booming, the problem is set to expand exponentially. Below is a map showing tons of carbon dioxide emmited per country. How much carbon dioxide does your country contribute?
Global weather patterns are changing and greenhouse gas issues are affecting people... right now. You can make a difference, become informed, speak out, lobby politicians and get involved at a community level.
Tuesday, July 7, 2009
Calculate your carbon footprint
If you visit www.stephentimms.org.uk, you can calculate how much carbon you emit while travelling to and from work. Then - on the same site - they'll tell you how you can erase that carbon footprint, easily.
This applies to companies as well as individuals. HSBC was the first bank to go 'carbon neutral' and BSkyB, the first
media company. How does that make you feel about those two companies?
Let's face it. We all leave a mess behind us.
The difference is, mature people clear it up afterwards.
Take action
If you like the action, why not give it a go? We don't want you to spend hours trying to find out how to get started on each action, so we've got some ideas here.
www.thec-changetrust.org
www.co2balance.com
www.earthday.net
www.bestfootforward.com
www.treesforcities.org
www.carbonneutral.com
www.carbonfootprint.com
www.eta.co.uk
www.targetneutral.com
www.sbsbsb.com
This applies to companies as well as individuals. HSBC was the first bank to go 'carbon neutral' and BSkyB, the first
media company. How does that make you feel about those two companies?
Let's face it. We all leave a mess behind us.
The difference is, mature people clear it up afterwards.
Take action
If you like the action, why not give it a go? We don't want you to spend hours trying to find out how to get started on each action, so we've got some ideas here.
www.thec-changetrust.org
www.co2balance.com
www.earthday.net
www.bestfootforward.com
www.treesforcities.org
www.carbonneutral.com
www.carbonfootprint.com
www.eta.co.uk
www.targetneutral.com
www.sbsbsb.com
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