What are the alternatives

Until a few decades ago it was generally thought that significant large-scale global and regional climate changes occurred gradually over a timescale of many centuries or millennia, hence the climate shifts were assumed to be scarcely perceptible during a human lifetime. The tendency of climate to change abruptly throughout human history has been one of the most surprising outcomes of the study of past climates. There is good evidence that some of the most pronounced climate changes involved a regional change of up to 5°C in mean annual temperature within a few decades, or even just a few years. These decadal-timescale transitions would presumably have been quite noticeable to humans living at such times. It is known that one of these short, cold, arid periods about 4,300 years ago had a profound effect on classical civilizations. Many of these civilizations could not adapt to the climate changes and collapsed, including the Old Kingdom in Egypt; the Akkadian Empire in Mesopotamia; the Early Bronze Age societies of Anatolia, Greece, and Israel; the Indus valley civilization in India; the Hilmand civilization in Afghanistan; and the Hongshan culture of China. It has also been shown that climate deterioration, particularly a succession of severe droughts in Central America during the Medieval Cold Period, prompted the collapse of the classic period of the Mayan civilization. Moreover, the rise and fall of the Incas can be linked to alternating wet and dry periods, which favoured the coastal and highland cultures of Ecuador and Peru. We know,

Positive or Negative Market Impacts; Majority of People Adversely Affected

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34. Climate change risks with increasing global temperatures however, that humans can survive a whole range of climates. The collapse of these urban civilizations, then, is not about climate making an area inhospitable; rather the society was unable to adapt to the climate changes, particularly changes in water resources. For example, for the Mayan civilization to have survived, it would have needed to recognize its vulnerability to long-term water shortages and should have developed a more flexible approach, i.e. developing new water sources, developing new means of conserving water, and prioritizing water use in times of shortage.

So climate change is an external pressure on a society, but it is the structure of the society, particularly how flexible it is, that determines whether it survives or not. This is an important lesson. As the weight of evidence strongly suggests that global warming will cause climate change, we have to make sure that og our global society and economy are flexible enough to deal with | these changes. The IPCC 2001 Report on Impacts, Adaptation j| and Vulnerability provides a very useful diagram of key societal Ü impacts and at what increased global temperatures they may occur (Figure 34). This is a valuable management tool as it shows how these five reasons for concern may vary in the 21st century. It is on this risk scale that we need to judge the cost of adaptation and mitigation versus the various regional and global impacts.

Adaptation and mitigation

The most sensible approach to preventing the worst effects of global warming would be to cut carbon dioxide emissions. Scientists believe a cut of between 60 and 80% is required to avoid the worst effects of global warming. But many have argued that the cost of significant cuts in fossil-fuel use would severely affect the global economy, preventing the rapid development of the Third World. The ratification of the Kyoto Protocol at the Bonn meeting in July 2001 will only amount to a cut of between 1 and 3% for the

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35. Projected global CO2 emissions with or without Kyoto developed world (Annex 1), while the developing world (non-Annex 1) will continue to increase their emissions (see Figure 35). So the second major aim of the IPCC is to study and report on the potential sensitivity, adaptability, and vulnerability of each national environment and socio-economic system because if we can predict what the impacts of global warming are likely to be, then national governments can take action to mitigate the effects. For example, if flooding is going to become more prevalent in Britain, then damage to property and loss of life can be prevented with strict new laws which limit building on flood plains and vulnerable coasts.

The IPCC believes there are six reasons why we must adapt to climate change. (1) Climate change cannot be avoided; (2) anticipatory and precautionary adaptation is more effective and less costly than forced last-minute emergency fixes; (3) climate change may be more rapid and more pronounced than current estimates suggest, and unexpected events, as we have seen, are more than just possible; (4) immediate benefits can be gained from better adaptation to climate variability and extreme atmospheric events: for example, with the hurricane risk, strict building laws and better evacuation practices would need to be implemented; (5) immediate benefits can also be gained by removing maladaptive policies and practices, for example, building on flood plains and vulnerable coastlines; and (6) climate change brings opportunities as well as threats. Future benefits can result from climate change. The IPCC has provided many ideas of how one can adapt to climate change; an example is given in Figure 36 of how countries can adapt to predicted sea rise.

The major threat from global warming is its unpredictability. Humanity can live in almost any extreme of climate from deserts to the Arctic, but only when we can predict what the extremes of the weather will be. So adaptation is really the key to dealing with the global warming problem, but it must start now, as og infrastructure changes can take up to 50 years to implement. For | example, if you want to change land use, e.g. building better sea j| defences or returning farmland back to natural wetlands in a 3 particular area, it can take up to 20 years to research and plan the appropriate changes. It can then take another ten years for the full consultative and legal processes; an example of this is the time it has taken to agree a strategy to expand London airports. It can take another ten years to implement these changes and a following decade for the natural restoration to take place (see Figure 37).

The other problem is that adaptation requires money to be invested now; many countries just do not have the money and elsewhere in the world people do not want to pay more taxes to protect themselves in the future as most people live for today. This is, of course, despite the fact that all of the adaptations discussed will in the long term save money for the local area, the country, and the world; we as a global society still have a very short-term view, usually measured in a few years between successive governments.

Retreat

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36. Model response strategies for future sea-level rise

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37. Lead times for response strategies to combat climate change

Technofixes, can we fix global warming?

How can we deal with global warming? We have seen that governments are slowly getting their act together to reduce carbon dioxide emission; however, there are concerns over how much this will cost. There has therefore been a lot of interest in 'alternatives' or 'technofixes' for solving the problem of global warming. There are four main areas of technofixes:

1. CO2removal from industrial processes can contribute substantially to a reduction in atmospheric CO2; however, further research and development is required to improve the performance and their application of these methods within the concepts of sustainable development.

2. We can use less energy and thus produce less carbon dioxide. t It is feasible to improve energy efficiency by 50% on average over j the next three decades, although this will require tough policy e u measures, like the introduction of a high-energy or carbon tax. An ¡j example is that efficiency in power generation can be increased by i 60% using advanced technologies in the field of gas turbines and ? fuel cells.

3. There are renewable/alternative energy sources, i.e. energy sources which do not produce a net amount of carbon dioxide in the atmosphere. Most promising in the short term is biomass, which by the year 2020 could produce a third of the global energy. When the biomass is growing it absorbs carbon dioxide from the atmosphere which is only returned when it is burnt as a fuel and thus there is no net increase in atmospheric carbon dioxide. Most promising for the long term is solar energy, while wind power is thought to be an excellent intermediate solution, particularly in countries such as the UK, where sunlight cannot be guaranteed. Many countries are also discussing renewing their nuclear programmes as a non-carbon-emission energy source, but problems of safety and dumping nuclear waste still remain the main objections.

Alternative energies are no longer the remit of the environmental NGOs; with the exception of some US oil companies, with Exxon/ Mobil (Esso in Europe) top of the list, most of the rest of the global business community is reacting rapidly to the need for different energy sources. In the last five years, companies like Ford and oil companies like BP and Shell have begun to pour billions of dollars into researching new technologies. Wind power is now mainstream, solar power is in rapid development, hybrid cars are on the roads. Cars that run on fuel cells, hydrogen, and compressed air are no longer pipe dreams.

4. There is the possibility of removing carbon dioxide from the atmosphere either by growing new forests or by stimulating the ocean to take up more. This idea is discussed in greater detail below in the iron hypothesis section.

All of these technologies make sense and a combination of them | could be used to combat global warming, although they each have j| their drawbacks. Removal of carbon dioxide during industrial 3 processes is tricky and costly, because not only does the CO2 need to be removed, but it must be stored somewhere as well. Removal and storage costs could be somewhere between $20 and $50 per tonne CO2. This would cause a 35% to 100% increase in power production costs. However, recovered CO2 does not all need to be stored; some may be utilized in enhanced oil recovery, the food industry, chemical manufacturing (producing soda ash, urea, and methanol), and the metal-processing industries. CO2 can also be applied to the production of construction material, solvents, cleaning compounds and packaging, and in waste-water treatment. But in reality, most of the carbon dioxide captured from industrial processes would have to be stored. It has been estimated that theoretically two-thirds of the CO2 formed from the combustion of the world's total oil and gas reserves could be stored in the corresponding reservoirs. Other estimates indicate storage of 90-400 GtC in natural gas fields alone and another 90 GtC in aquifers. Oceans could also be used to dispose of the carbon dioxide. Suggestions have included storage by hydrate dumping, i.e. if you mix carbon dioxide and water at high pressure and low temperatures it creates a solid or hydrate which is heavier than the surrounding water and thus drops to the bottom. This hydrate is very similar to the methane hydrates discussed Chapter 7.

The major problem with all of these methods of storage is safety. Carbon dioxide is a very dangerous gas because it is heavier than air and causes suffocation. An important example of this was in 1986, when a tremendous explosion of CO2 from Lake Nyos, in the west of Cameroon, killed more than 1,700 people and livestock up to 25 km away. Though similar disasters had previously occurred, never had so many people and animals been asphyxiated on such a scale in a single brief event. What we now believe happened was that dissolved CO2 from the nearby volcano seeped from springs beneath the lake and was trapped in deep water by the weight of water above. In 1986 there was an avalanche which mixed up the lake waters, resulting in an explosive overturn of the whole lake, and all the trapped carbon dioxide was released in one go, proving that the storage of carbon dioxide is very difficult and potentially lethal. With ocean storage there is the added complication that the ocean circulates, so whatever carbon dioxide you dump, some of it will eventually return. Moreover, scientists are very uncertain about the environmental effects on the ocean ecosystems. At the moment, therefore, we have no estimates of the amount of CO2 that can be safely stored.

Ultimately, a combination of improved energy efficiency and alternative energy is the solution to global warming. From the safety and environmental perspective, the storage of carbon dioxide either underground and/or in the ocean is really not feasible, however helpful this would be in the short term.

Iron hypothesis

As we have seen, global warming is constantly on the political agenda, even if politicians do not like to mention it. The problem, however, is that cutting carbon dioxide emissions has a huge economic price tag. So scientists and politicians are always looking for a quick fix or a 'technofix' for global warming. The late Professor John Martin has put forward one of the most controversial ideas yet. He suggested that many of the world's oceans are underproducing. This is because of the lack of vital nutrients, the most important of which is iron which allows plants to grow in the surface waters. Marine plants need minute quantities of iron and without it they cannot grow. In most oceans enough iron-rich dust gets blown in from the land, but it seems that large areas of the Pacific and Southern Ocean do not receive much dust and thus are barren of iron. So it has been suggested that we could fertilize the ocean og with iron. This would stimulate marine productivity. The extra | photosynthesis would convert more surface-water carbon dioxide j| into organic matter. When the organisms die the organic matter 3 drops to the bottom of the ocean, taking with it and storing the extra carbon. The reduced surface-water carbon dioxide is replenished by carbon dioxide from the atmosphere. So, in short, fertilizing the world's oceans could help to remove atmospheric carbon dioxide and store it in deep-sea sediments. Experiments at sea have shown that the amount of iron required is huge, and as soon as you stop adding the extra iron, much of this stored carbon dioxide is released. There is also another, darker, side to this iron hypothesis. It seems that because of industrialization and also worldwide land-use changes, there is about 150% more dust in the atmosphere than 200 years ago. This extra dust has increased the ocean's ability to take carbon dioxide out of the atmosphere. So our dirty atmosphere is literally helping us against global warming. However, under the Kyoto Protocol countries are encouraged to start expanding forests and preventing soil erosion to draw carbon dioxide out of the atmosphere. This will ultimately lead to a decrease in dust. Calculations by Dr Andrew Ridgwell at the

University of British Columbia (Canada) and myself suggest that a significant proportion of the extra carbon dioxide stored on land under the Kyoto Protocol could be returned to the atmosphere, because the decrease in overall dust will start to limit iron in the ocean and thus productivity. The reduced ability of the ocean to suck out atmospheric carbon dioxide will, over hundreds of years, wipe out the short-term gain from planting all those new forests.

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