Jamaica like the rest of the world currently relies heavily on oil and to a lesser extent coal, for its energy needs. Fossil fuels are however nonrenewable, that is, they draw on finite resources that will eventually dwindle, becoming too expensive or too environmentally damaging to retrieve. Industry experts estimate that in fifty years commercially extractable oil reserves will be completely depleted. In contrast, renewable energy resources – such as wind and solar energy – are constantly replenished and will never run out.

The production of energy worldwide is therefore dependent on petroleum based products such as oil, coal and natural gas. The production of energy therefore on a global scale therefore has a number of cumulative and site specific environmental impacts. In particular the production of energy has a direct impact on the Oceans of the world. This article will attempt to highlight a few of these examples.

We can examine the impact of oil from two aspects; the first is global perspective and the second is the local or regional focus.

The amount of petroleum products ending up in the ocean is estimated at 0.25% of world oil production: about 6 million tons per year. Seagoing tankers carry 60% of all oil extracted. The oceanic pollution is caused when these ships flush their tanks with seawater. A smaller percentage comes from passenger ships and freighters draining water ballast from their fuel tanks.

The greatest volume of petroleum products dumped into the ocean is carried there by rivers. It represents more than triple the quantity coming from all tankers and other ships. Oil and other petroleum products are discharged into rivers and the ocean by many industrial enterprises, including oil refineries and oil storage installations, The quantity of petroleum products dumped each year into the sewage network by gasoline stations twice exceeds the amount resulting from ship disasters.

The risks and responsibilities associated with oil in the sea should be put in their true perspective.

By far the highest contributor to oil in the ocean (about 37 per cent) results from a mix of materials and wastes which make up urban run-off and the discharge from land - based industrial plants. These materials reach the sea via storm water drains, sewage outfalls, creeks and rivers.

Another seven per cent is oil which seeps naturally out of fissures in the sea bed. Oil and tar stranded on the beaches of South Australia and Western Victoria, for instance, was first noticed by European settlers during the early 1800s. Now it is known to come from cracks in the ocean seabed and is particularly noticeable after earth tremors in the region.

Only 14 per cent of the oil in the sea is directly attributable to the world's oil industry. Two per cent of this occurs in spills during the exploration and production phase from rigs and platforms, and 12 per cent is attributable to accidents involving oil tankers.

Another 33 per cent occurs during the operation of vessels other than those used by the oil industry. Usually these are cargo vessels which may be involved in collisions which spill fuel oil or they may discharge waste oil from ballast tanks during a voyage. The remaining 9 per cent of oil in the oceans is absorbed from the atmosphere.

Impact on the Caribbean

The impact of the petroleum based energy industry on the Caribbean has been very significant. Many small island states in the Caribbean like Jamaica depend solely on imported fuel. The transshipment of fossil fuel has some direct environmental impacts on our oceans and coastal resources.

Locally, especially in coastal regions, a sudden spill of oil into the sea can have catastrophic consequences that are usually short-lived. There have been a few incidences of oil spills which have resulted in serious damage to the fishing industry as well as to the tourism product (wide sandy beaches). Oil is toxic to marine organisms such as the coral polyps which are the basic components of corals. Oil will, after some time, fall out of the water column will kill benthic (sea-bottom) ecosystems such as seagrass beds. Oil slicks can also smother the roots of mangrove plants found at the waters edge.

It is important to note that the destruction of these important tropical ecosystems can ultimately result in the loss of the protective role they serve. Hence the coral reef can no longer provide the wave breaking function it normally serves. Seagrass beds and mangrove environments will cease to provide nursery areas for juvenile species which are commercially important (such as lobster, shrimp and fin fish).

So what are the solutions to these direct impacts? Regional authorities must have oil spill contingency plans in place to respond to accidents and other incidents of the release of crude oil or petroleum products in to the coastal environment.

No two oil spills are the same because of the variation in oil types, locations and weather conditions involved. However, broadly speaking, there are four main methods of response.

1. Leave the oil alone so that it breaks down by natural means.

2. Contain the spill with booms and collect it from the water surface using skimmer equipment.

3. Use dispersants to break up the oil and speed its natural biodegradation.

4. Introduce biological agents to the spill to hasten biodegradation.

Often the response involves a combination of all these approaches:

If there is no possibility of the oil polluting coastal regions or marine industries, the best method is to leave it to disperse by natural means. A combination of wind, sun, current and wave action will rapidly disperse and evaporate most oils. Light oils will disperse more quickly than heavy oils.

Spilt oil floats on water and initially forms a slick that is a few millimetres thick. There are various types of booms which can be used either to surround and isolate a slick, or to block the passage of a slick to vulnerable areas such as the intake of a desalination plant or fish farm pens or other sensitive locations.

Boom types vary from inflatable neoprene tubes to solid, but buoyant material. Most rise up about a metre above the water line. Some are designed to sit flush on tidal flats while others are applicable to deeper water and have skirts which hang down about a metre below the waterline. Skimmers float across the top of the slick contained within the boom and suck or scoop the oil into storage tanks on nearby vessels or on the shore. However booms and skimmers are less effective when deployed in high winds and high seas.

These act by reducing the surface tension that stops oil and water from mixing. Small droplets of oil are then formed which helps promote rapid dilution of the oil by water movements. The formation of droplets also increases the oil surface area, thus increasing the exposure to natural evaporation and bacterial action.

Dispersants are most effective when used within an hour or two of the initial spill. However they are not appropriate for all oils and all locations. Successful dispersion of oil through the water column can affect marine organisms like deep water corals and seagrass. It can also cause oil to be temporarily accumulated by subtidal seafood. Decisions on whether or not to use dispersants to combat an oil spill must be made in each individual case. The decision will take into account the time since the spill, the weather conditions, the particular environment involved and the type of oil that has been spilt.

Most of the components of oil washed up along a shoreline;can be broken down by bacteria and other micro-organisms into harmless substances such as fatty acids and carbon dioxide. This action is called biodegradation. The natural process can be speeded up by the addition of fertilising nutrients like nitrogen and phosphorous which stimulate growth of the micro-organisms concerned. However the effectiveness of this technique depends on factors such as whether the ground treated has sand or pebbles and whether the fertiliser is water soluble or applied in pellet or liquid form.

Conclusions.

There are however some wider issues to consider. The use of petroleum products for the production of all forms of energy has implications for global warming and climate change. The persistent dependence of fossil fuels has accelerated the production of Carbon Dioxde (CO₂) which is recognized as a green house gas. Global warming is likely to impact the planet’s climates (changes to weather patterns), changes in oceanography (currents and tides) and very critically sea level rise. These issues are highly likely in the near future, prove to be very challenging to all countries but especially small island developing states.

http://www.aip.com.au/education/projects/pt_oceans/

http://www.gcrio.org/gwcc.part1.html

http://www.daac.gsfc.nasa.gov/CAMPAIGN_DOCS/OCDST/shuttle_oceanography_web/