Organic Farming

 

Organic agriculture is a safe, sustainable farming system, producing healthy crops and livestock without damage to the environment. It avoids the use of artificial chemical fertilisers and pesticides on the land and the use of genetically modified organisms is prohibited. It relies instead on developing a healthy fertile soil and growing a mixture of crops. In this way the farm remains biologically balanced, with a wide variety of beneficial insects and other wildlife to act as natural predators for crop pests and a soil full of micro-organisms and earthworms to maintain its vitality. Animals are reared without the routine use of the array of drugs, antibiotics and wormers, which form the foundation of most conventional livestock farming.

Organic farming, now defined under European Union law, bans chemical fertilisers and pesticides, and uses rotations, mixed cropping and builds up soil fertility using pea crops rather than artificial fertilisers. Animals raised organically, without systematic use of antibiotics, have a strong immune system resistant to diseases and rarely need medicine. Organic yields are usually between 25% and 30% lower than in conventional farming, but the risk of disease is much lower.

Organic farming practices are better for the environment than practices used on conventional farms. A recent study of organic and conventional farms concluded that the organic farms held higher densities of birds than conventional farms, especially in winter. Breeding densities of skylarks were also strikingly higher on organic farms. Organic farming has clearly defined standards for the environment and conservation set down by the Soil Association and others.

Organic farms cover over 1.5% of the UK farmed area. In Sweden they cover 10% and in Italy 5%. The UK imports 70% of the organic food consumed and the demand is growing by 40% a year. In 1998 the Government spent £3,000 million on subsidies to farmers but only 3% of this was for agri-environmental schemes. Just 8% of the latter was allocated to help organic farmers (£6.2 million). More Government money was provided in 1999 through the Organic Farming Scheme, but this scheme was closed in August 1999 after the entire funding for 1999 and 2000 was used up in 4 months. In October a further £10 million was allocated but this was not expected to last for longer than 6 months.

The Soil Association commissioned a MORI survey in June 1999. One third of the public buy organic food perceiving it as:

• Healthy/better for you 53%
• Tasting better 43%
• GM free 30%
• Better for the Environment 28%
• Higher animal welfare 24%

The clear advantage of organic farming in nearly all agricultural policy areas, the current level of demand and the current policy opportunities mean organic production should now be taken up as a mainstream policy option for UK agriculture.

Further information:

  Soil Association

Types Alternative Energy

Renewable energy refers to power generated by a renewable source. When the energy is generated , the resource is not depleted or used up They are naturally replenished and can either be managed so they last forever or their supply is so enormous humans can never meaningfiully deplete them. Unlike fossil fuels renewable energy sources do not release C02 as a by-product into the atmosphere. As the amount of fossil fuel resources on Earth decreases it is becoming increasingly important to find and utilise alternative fuels. Examples are.-

WIND POWER.

Air moves around the Earth because of the differences in temperature and atmospheric pressure Wind turbines harness the movement of air to produce energy. The wind turns the blades which turn a rotor shaft; the resultant mechanical power is used to drive an electricity generator. Wind turbines are often grouped together in wind farms. Wind power has very promising potential in the UK as we live in the path of Atlantic depressions (low- pressure systems) which bring windy weather. The UK currently has over 20 wind farms that could be supplying 10% of the UK's electricity by 2025. Wind farms provide a clean source of energy, but some people do not like their visual impact and the fact that they can be noisy in windy conditions. Suitable locations are often in areas of scenic beauty and so careful consideration needs to be given before they can be built. It is estimated that the UK has a very large offshore wind resource but it is not thought to be financially viable at present.

SOLAR POWER.

Solar power is the term used to describe energy derived directly from the Sun. The Sun provides the basis of energy for all living things. Sunlight has been utilised by humans for drying crops and heating water and buildings for millions of years. Solar energy is free and will never run out. We can use solar panels to turn the Sun's energy into useful energy. There are a number of ways to do this.

Passive Solar Heating.
Houses can be designed with large windows in the south and small windows in the north facing walls. This would allow natural light and heat from the Sun to be used to its full potential and reduce the need for electricity.

Active Solar Heating.
Solar power can be used to heat large bodies of water mainly for domestic hot water systems but also swimming pools.

Photovoltaics.
Photovoltaics allow the direct conversion of solar radiation into an electric current by the interaction of light with the electrons in a semiconductor cell. As development in solar technology has increased it has become much cheaper and the UK is starting to invest in the technology

BIOFUELS.

This is the term used to describe plant material and animal waste which can be burnt to produce energy. It is the oldest source of renewable energy known to humans. Unlike other renewables biomass energy does release C02 but only as much as was removed through photosynthesis during the plant's lifetime. Burning fossil fuels, by contrast, returns C02 to the atmosphere that has been locked away in the Earth's crust for millions of years. Crops can be grown with the purpose of being burnt to produce energy, e.g willow and oil seed We can also extract methane from waste landfill sites and burn it to produce energy. Methane is a powerful greenhouse gas and burning it would reduce the amount in the atmosphere.

HYDRO ELECTRIC POWER (HEP).

On the Earth water is neither created or destroyed but is constantly moved around. Water evaporates from the oceans, forming clouds, falls out as rain and snow, collects into streams and rivers, and flows back to the sea. This is known as the Water Cycle. All this movement provides an enormous opportunity to create useful energy. HEP uses the force of moving water to create electricity. However HEP stations often require large dams, which can disrupt ecosystems and displace people. There are a number of large scale HEP stations in Britain. In Scotland they provide a considerable amount of energy. Unfortunately there is little room for further development of large scale HEP stations and the potential of small scale ones is being investigated.

GEOTHERMAL ENERGY.

Rocks under the Earth's crust contain naturally decaying radioactive materials like uranium and plutonium producing a continuous supply of heat. The amount of heat within 10,000 metres of the Earth's surface contains 50,000 times more energy than all the oil and gas resources in the world. Geothermal energy is power generated by harnessing this heat. Wells are used to pipe steam and hot water from deep within the Earth, up to the surface. The hot water is then used to drive turbines and generate electricity. The regions with highest underground temperatures are in areas with active or geologically young volcanoes. These "hot spots often occur around the Pacific Rim. In the UK at a depth of 1500-3000 metres below the surface there are some aquifers that contain water at very high temperatures which can be pumped to the surface and used in heating schemes.

TIDAL POWER.

The idea is very similar to HEP. A dam-like structure is constructed across an estuary to trap a high tide of water and then let it pass through turbines to generate electricity The water flow can generate electricity on the falling tide only, or on the falling and rising tide. The Rance Estuary in France is an example of a successful plant. The UK has potential to widely use tidal power with the Severn and Mersey estuaries being possible sites.

WAVE POWER.

Ocean waves are a concentrated form of wind energy. Friction develops between air and water as wind blows across the water, and waves are produced as energy is transferred between these elements. Taking the motion of the waves, and translating it into mechanical or electrical energy, generates energy from waves. The UK has the potential to exploit a great deal of energy from wave power. There are 2 types of instruments that can generate electricity from wave energy: floaters and sitters. Salter's Duck and Cockerell's Raft are floaters and Vicker's "Duct is a sitter.

Salter's Duck.
This design can extract approximately 90% of the energy from a wave It is made up of a chain of about 25 floats. As they bob up and down on the water a pump is driven and electricity is generated.

Cockerell's Raft.
Lines of rafts are placed at right angles to the wave front. Between the rafts are hydraulic motors or pumps, which convert the energy to high pressure that then drives the turbines.

Vicker's Duct.
Water goes up and down a submerged tube and as the pressure changes water is squirted out and electricity generated.

Marine Conservation

 

Our seas are priceless. Up to half of the UK’s wildlife is found in the ocean and new and wonderful discoveries are being made all the time. The seas around our shores are home to an amazing variety of animals, including dolphins, turtles, seals and sea horses as well as the mighty orca- the killer whale. We even have deep-sea coral reefs- rich and diverse like those found in the tropics.

A combination of rising sea levels and rising global temperatures are threatening thousands of hectares of Britain’s shoreline and vital wildlife habitats. As climate scientists predict that sea level rise will accelerate it is estimated that 10,000 plants and nature reserves will be at risk of inundation. The projected impacts of climate change include :-

• Diversion of ocean currents. This may be particularly important for the UK as the warm Gulf Stream maintains a milder climate than would be expected at our latitude. Shifts in currents could alter geographic distribution of fish populations by varying temperature, salinity and nutrient availability.
• Increased frequency and intensity of storm events. This may damage coastal habitats and coral reefs.
• Shifts in composition and geographic distribution of ecosystems. These have potential impacts on biodiversity and fisheries.
• Melt-down of Polar ice caps. This will have subsequent impact on salinity levels and ocean temperatures- potentially reducing the temperature at the northerly and southerly latitudes.
• Sea level rise. This will result from the melt-down of ice caps and is considered to be the most significant and destructive impact of global warming.

The North sea is one of the world’s major fishing grounds, supporting a variety of commercial fish stocks. Pelagic fish taken are mackerel and herring, and demersal species such as cod, haddock, saithe and whiting are fished extensively. Bottom living fish, especially plaice and sole are also exploited. Some species are not taken directly for human consumption, such as Norway pout, sandeels and sprats, most of which are made into fishmeal for use in intensive livestock farming. Rapid technological advances made in recent years have allowed the efficiency of fishing fleets to increase, and numbers of boats employed in fishing have increased in recent decades. Many species such as herring, cod, skate and haddock have been so heavily fished that their populations have fallen to critical levels. If the natural balance is greatly upset by commercial fishing there will be far reaching consequences on marine ecosystems. The possible links between sandeel fisheries and the breeding failure of seabirds, especially arctic terns and kittiwakes are well documented.

Both natural and synthetic chemical compounds contaminate the marine environment. Chemicals enter it via several pathways :-

• Point-source discharges e.g. from sewage treatment works and oil rigs.
• Diffuse discharges e.g. from agriculture and shipping.
• Atmospheric deposition e.g. from waste incineration plants.

Chemicals are used by most industries at some stage in the production process and are often present in the finished product. The major contributors to chemical pollution in the marine environment are :

• Agriculture- conventional farming practices rely heavily on the use of agro-chemicals to prevent damage by pests and weeds. Widespread use of pesticides and herbicides inevitably leads to the contamination of streams and rivers which discharge to the marine environment.
• Chemical and pharmaceutical manufacturing. - Much of the UK’s large chemicals industry is situated at the coast. By-products and waste from production are usually discharged to the sea directly or via sewage treatment works. In 1987 12 billion litres of industrial waste drained through public sewers every day.
• Offshore oil and gas.- Offshore oil and gas production requires the use of hundreds of different chemicals , including lubricants, corrosion inhibitors, demulsifiers, biocides and surfactants. These are discharged to the marine environment in produced water and drill cuttings and directly from the rigs in washings.
• Transport. - most seagoing vessels , from cargo ships to yachts, use some form of antifoulant paint on the hull to prevent colonisation by marine organisms. Many antifoulants are designed to leach chemicals into sea water.

Chemical pollution can affect marine life at every trophic level. The impact on species’ biology are very complex and poorly understood, though some end effects are well documented, particularly on the reproductive system :

• Intersex is where an individual has both male and female intermediary characteristics. This has been found in high levels in some tiny crustacea in coastal waters. In UK industrialised estuaries males of bottom-dwelling fish such as flounder have synthesised the female egg yolk protein vitellogenin and developed egg cells in otherwise normal testes.
• Imposex is where an individual of a species has the sexual characteristics of the opposite sex superimposed on its own. This has been highly evident in the dogwhelk, where females have developed male genitalia as a result of exposure to the antifoulant tributyltin (TBT).
• Hermaphroditism is where an individual has both male and female reproductive organs. In 1998 4% of polar bears on two Arctic islands were found to be hermaphroditic- high PCB levels were found in their fat.

WHAT CAN BE DONE ?

More Marine Protection Areas should be set up with more effective protection for the UK’s marine wildlife, habitats and the people who depend on the sea for their living. A Marine Protected Area is similar to a nature reserve on land. It’s an area where human activities take place in harmony with nature. It provides food, shelter, breeding and nursery grounds for marine wildlife. It offers greater protection for species including dolphins, corals, sea horses and habitats such as grass meadows. It can also offer better protection from the impacts of oil pollution (3 of the world’s biggest oil spills occurred around British coasts), shipping and drilling for oil and gas.

A Fishing-Free Zone would greatly benefit our fish stocks. If fish are left undisturbed they regenerate themselves very quickly and efficiently. Fishing-Free Zones are relatively easy to enforce as by using satellite tracking we can throw a virtual “fence” around any area.

For further information please see the following web sites:-

• Marine Conservation Society
• WWF UK: www.wwf-uk.org/news or www.wwf-uk.org/orca.

Global Warming

Climate Change - Introduction Sheet

The prospect of global climate change is a matter of genuine public concern The amount of carbon dioxide (C02) in the atmosphere is increasing and the temperature of the earth's surface is rising Although there is a lot of uncertainty about the magnitude and consequences of these developments, the balance of informed opinion is that mankind is having a discernible effect on the climate and scientists believe there is a link between the amount of C02 in the atmosphere and increased temperature.

Faced with this uncertainty, adopting a precautionary approach to climate change is the only sensible way forward in these circumstances This is why the Kyoto agreement has set itself a goal to reduce the developed world's emissions of greenhouse gases by 10%, from a 1990 baseline, by the year 2010.

As the industrial revolution created more demands for energy, coal replaced wood as the most important fuel At the beginning of the last century, oil became significant as a fuel and now gas is the fastest growing source of hydrocarbon energy Switching from coal to gas as the primary fuel for generating electricity can result in a 50% reduction in C02 emissions per unit of electricity generated.

Recent technological advances have made renewable energy more economically accessible. The annual growth rate for wind and solar photovoltaics generated electricity is around 20-30% Other sources of renewable energy are being actively pursued throughout the world and will contribute to broaden the energy mix

However, hydrocarbons are expected to remain as the dominant source of energy for the foreseeable future.

Not surprisingly perhaps, history shows that energy efficiency in industry improves with time Today combined cycle and combined heat and power electricity generation, improved insulation and design of buildings and a new generation of vehicles will continue this trend of improving energy efficiency Recent developments in fuel cell technology point the way to further improvements in efficiency and reduced emissions, particularly if hydrogen is used as a fuel

Recent evidence shows reservoirs are powerful sources of greenhouse gas emissions. Hydroelectric power has long been thought a relatively pollution free source of energy, but evidence is emerging that reservoirs are powerful sources of greenhouse gas emissions.

Recent research suggests that up to half of Brazil's hydroelectric reservoirs have a global warming capacity similar to that of a fossil-fuel fired power plant

Although the problem is thought to be most significant in tropical areas, the World Commission on Dams recently warned that greenhouse gas emissions have been found at all 30 reservoirs from which measurements have been taken

This research is prompting calls for reservoir emissions to be included in national emissions inventories, a notion until recently dismissed. Including this source could likely have major effects for some countries, such as French Guyana, Ghana, Norway and the US

Rotting vegetation, particularly a problem in tropical areas - releases significant amounts of carbon dioxide and methane Methane is a hydrocarbon and its main impact is as a greenhouse gas with 21 times greater global warming potential than carbon dioxide