The “greenhouse effect” is a natural phenomena caused by “insulating” gases in the atmosphere that allow life on Earth as we know it today – without it the Planet would be 20°C cooler. The “enhanced greenhouse effect” is that attributed to man-made gaseous contributions to the atmosphere – which are around 4% of the total greenhouse effect.
The possible impacts of global warming could include rising sea levels, changes in ecological systems, changes in agricultural domains, droughts, floods and disease spread. Although these predictions are yet to be validated, the world has accepted the need to address global emissions based on the precautionary principle. Regardless of the unknowns, it makes sense to be more efficient and thus reduce emissions.
Climate change and greenhouse emission abatement has been internationally embraced although there are strong opinions around the world that there are many inconsistencies in the science driving the politics. One thing is certain, Man’s activities are adding to the Earth’s atmosphere with rising carbon dioxide levels due to industrialisation. Less certain is the extent to which this is responsible for global warming. Even more uncertain are the likely impacts of global warming on sea levels, agriculture, health, water resources, ecosystems and weather. Thus, the argument maintaining the greenhouse momentum is that we cannot afford to wait for perfect knowledge as it will maybe take centuries to confirm climate model predictions.
As Australia now produces more greenhouse gases per capita than any other country (1.4% of global emissions with 0.3% of the world’s population), we are seen as a rebel having bucked at international pressure starting at Kyoto. However, the use of such statistics in isolation could be considered unfair – failing to consider the energy intensive nature of Australia’s contribution to the world economy and food supply.
The difficulty with assessing the issue of global warming is the reliance on external data and interpretations. The ‘official’ reference body is the United Nations Intergovernmental Panel on Climate Change (IPCC). Data and interpretations from this body are scrutinised by thousands of “experts”. However, there is also a large body of scientists, the “sceptics”, who reject the IPCC findings claiming them to be less than stringent in applying due scientific process.
The temperature we experience is a function of energy from the Sun being trapped near the Earth’s surface by a small fraction (2%) of the atmosphere called “greenhouse gases”, mostly water vapour (67%), in the atmosphere. There have been many causes of temperature change during the Earth’s history, well before the advent of man and before the Industrial Revolution.
Regardless, there has been so much reporting on “Global Warming” that most people, including laymen, eminent scientists, environmentalists, politicians and journalists, accept significant climate change is being caused by human activities. Also generally accepted that are the predictions of looming disaster, based on historical data and computer modelling. Sceptics would say that many of the prophets of doom have become propagandists to promote self-interests; for example scientists are gaining vast grants for research.
The IPCC has concluded that, although it is difficult to distinguish between human activity and natural climate variation, there is a “discernible human influence” on climate.
The Earth’s natural CO² cycle involves massive annual amounts of CO² movement in and out of the atmosphere, some 200 billion metric tons. Human activities (anthropogenic) add about 7 billion metric tons, <5% of the annual exchange. This is claimed to be enough to put the system out of balance – with Nature only absorbing about half of Man’s emissions.
Humans have likely had an effect on climate through population growth, agriculture, industrial activity, building and transport. The records show global warming over the past 150 years and a large percentage increase in CO² contributed to by anthropogenic output. However, the net longer-term impact, positive or negative, heating or cooling, is debatable.
The general concern is for ongoing rising CO² and other greenhouse gas levels as these gases remain in the atmosphere for decades to centuries – leaving a long-term legacy of dubious consequences for the planet. These could include impacts on health, sea levels, storms, agriculture, water availability, flooding ecosystems and so on.
The desire to radically change our socioeconomic world to reduce CO², through suggested measures such as removal of the combustion engine, reduction of fossil fuel usage or cessation of coal mining, has yet to take into account the practicalities of such a move – or adequate replacement fuel options.
Fossil fuels provide around 75% of the world’s energy needs and, being diminishing resources, alternatives will eventually be required. Nuclear energy, although also finite, may need expanded usage to maintain required energy supplies as renewable energy sources are cost restrictive and some have serious associated environmental impacts.
Carbon dioxide abatement is not a fad that will go away and, notwithstanding coal fuel is vital to the world economy, it is the most targeted greenhouse source.
Each fossil fuel still has a role to play in the world’s energy mix. Coal has some advantages over oil and gas, being abundant and well spread. While Annex B countries are reducing fossil fuel emissions, the less developed countries (Non Annexe B) are actually increasing fossil fuel usage – herein lies the a fundamental flaw in the Kyoto Protocol.
In the end, reality must dictate a future for coal. It will be based on a cleaner electricity generation industry. Of all the currently investigated clean coal technologies, coal gasification technology is mooted to have the best chance of success. An Integrated Gasification Combined Cycle (IGCC) power plant can produce electricity as well as hydrogen for transportation fuels and for “distributed generation” in the future.
The alternatives to utilising coal are grim and unpalatable at present, requiring either incredibly expensive alternative energy technologies, or the burning of more oil and gas, or, if not, an increase in nuclear generation.