International Action about Global Warming
Now let us turn to what the world is doing about the problem. So far as world science is concerned, I have already mentioned the IPCC and its work in producing authoritative assessments. The influence of the IPCC 1990 assessment assisted the world's politicians meeting in Rio in 1992 in the formulation of the Framework Convention on Climate Change (FCCC) - a new convention to which countries agreed and which President George Bush signed for the United States. The FCCC's stated objective is the stabilization of greenhouse gas concentrations in the atmosphere at levels and on a time scale that would ‘prevent dangerous anthropogenic interference with the climate system' and that are consistent with sustainable development. Since then regular meetings of the Parties to the Climate Convention have been considering the action that should be taken. The Kyoto Protocol, agreed in 1997, formulates arrangements for the first binding commitments by nations, but it has yet to be ratified.
Why should we be concerned?
Let me digress now for a minute and consider just why we should be concerned about climate change. It is a problem that is well downstream; many of us will not be much affected ourselves but it is going to affect our children and our grandchildren. We are bound to ask therefore questions about the sort of relationship we should have to the earth that is our home and to the rest of creation with whom we share the earth. Let me suggest that a helpful picture of this relationship can be found in the early chapters of the Judaeo-Christian scriptures. Humans were placed in a garden to care for it. We are encouraged to see ourselves as gardeners of the earth.
Gardens suggest four things. They are there to provide food, water and resources for us, for human life and industry. They are also places of beauty and diversity - we cherish and spend time in our gardens and we visit special gardens - all part of our human enjoyment. We like to think that other living creatures also enjoy gardens too. The birds that join the dawn chorus at four in the morning obviously enjoy it very much; I enjoyed them too as I heard them in Cambridge this morning. And then gardens are places where we can be creative: we landscape them and create new varieties of plants or other creatures for beauty and for benefit. Our science and technology can help us to be better gardeners and to make the world a better place; although, just how technology should be applied is something we need to debate carefully. Finally, gardens are there for future generations. And that is something that those of us who have children and grandchildren, certainly appreciate. It is our children and our grandchildren who will experience the impacts of climate change. I remember in 1990 when the first IPCC report came out, the Prime Minister, Margaret Thatcher showed a lot of interest. I was invited to present it to her cabinet at the time. As I walked out of that meeting, one of the cabinet ministers asked me, "When's all this going to happen?" I replied that in 20 or 30 years we can expect to see some large effects. "Oh" he said, "that's OK, it'll see me out". But it won't see his children or grandchildren out.
Christians and other religious people believe that we've been put on the earth to look after it. Creation is not just important to us, we believe also it is important to God and that the rest of creation has an importance of its own: for these reasons we should be good gardeners. But in many ways we are not being good gardeners. Let me give you just two examples, other than the one of global pollution I've been talking about. We've already lost or seriously degraded some 10% of the garden's soil - a loss that continues largely unabated because of erosion and bad practice. Then, we are destroying forests, important forests. When I say "we" I mean "we" the human race of which we are part. We are party to the destruction, we allow it to happen, in fact it helps to make us richer. We really need to take our responsibility as ‘gardeners' more seriously.
Reducing carbon dioxide emissions
Let me return to climate change and what action can be taken. Much of the action has to be taken in the energy sector because most of the carbon dioxide that enters the atmosphere comes from energy production or use. Fig 16 shows anthropogenic carbon dioxide emissions since the industrial revolution; it also shows projections to the year 2100 made by the World Energy Council (WEC, the body that links the world's energy industries) under different assumptions. Curves A and B in fig 16 are "business as usual" projections, with large growth in emissions and even larger growth in energy use. Curve C the WEC describe as the ‘ecologically driven' scenario. The WEC believe curve C to be achievable, but only if we are really serious about being more careful and efficient in our use of energy, and also if we stimulate rather rapidly the growth of energy generation from renewable resources. Under projections A and B, carbon dioxide concentrations continue to rise to 600 or 700 ppm by 2100. Curve C is the only projection of the three that approaches stabilization of carbon dioxide at around 450 ppm.
A scenario such as C in fig 16 will only be realized if there is concerted international action. There are three principles that are frequently put forward as those that should govern such action. First there is the Precautionary Principle that is included in the Climate Convention and that states that that the lack of full scientific certainty should not prevent appropriate action being taken. The second is that polluters should pay for the damage of their pollution, a well known principle that has been built into environmental legislation for a long time. It can be applied, for instance, through the taxation of pollution or through the setting up of trading arrangements.
The third principle, the most difficult to apply, is that of equity - intergenerational equity and international equity. At the moment 55% of carbon dioxide emissions are produced by the richest one sixth of the world's population (fig 17), the United States alone being responsible for 25%. Just 3% is emitted by the poorest one sixth of the world. There is obviously a great inequity here. The Climate Convention recognizes this inequity by a clause that states that, because the industrialized countries have benefited so much from fossil fuel burning, they should take the lead and the first action in combating the problem and reducing their emissions. The formulation of the Kyoto Protocol follows this lead.
To illustrate the sort of action that is necessary and the associated difficulties, I present a proposal put forward by the Global Commons Institute called Contraction and Convergence shown in fig 18. The envelope curve in the figure shows a profile of emissions that would stabilize atmospheric carbon dioxide at about 450 ppm although very similar diagrams could be produced for different stabilization levels. The first part of the proposal is that the world as a whole agrees to follow that envelope curve - that is the ‘contraction' part of the proposal. Also shown is the share of emissions up to the present from different countries or groups of countries. The second part of the proposal is that eventually, say from 2030, carbon dioxide emissions should be allocated to countries so as to share the emissions equally between all human beings. From 2030, the figure illustrates that allocation. Between now and 2030, emissions from countries need to converge to their 2030 allocations.
You will immediately say that such goals are completely unrealistic. But there is a third part of the proposal that allows for trading of emissions. Those that have more than they need can sell to those who want to emit more. The effect of the trading would be to move money from rich nations to poor nations; that money could be used to help poor nations industrialise in sensible ways and to develop appropriate non fossil fuel energy systems.
Now you will see enormous problems, political, practical and even possibly ethical by the details of the Contraction and Convergence proposal, or indeed of any other proposal that can be envisaged. But is does well illustrate some of the essential principles that have to underlie the necessary action and the scale and the enormous challenge it presents to all countries of the world.
Let me now turn from the politics and in considering the practical changes that could be made in energy use, I will just use the example of buildings. About 40% of electricity is used in buildings. Much can be done to reduce this at little or no cost - or in many cases with actual savings in cost. Better building standards, better heat insulation, more efficient lighting, use of direct solar energy to heat buildings, use of local combined heat and power plants are just some of the possibilities. The basic technology to do a great deal is already available. But it is not enough to demonstrate what can be done on a few demonstration buildings. Millions of buildings have to be brought to a much higher standard of energy efficiency. That is a very large challenge to governments, to industry and indeed to all of us.
Changes have not only to be made in the way we use energy; changes are also required in the way energy is generated. We have to move away from using fossil fuels and learn to use renewable energy sources such as biomass (eg fast growing willow), wind and solar energy. Again, much of the technology is available but resources and incentives need to be put into place to enable growth of renewable energy on the scale required. The UK is slow in this compared to some other developed countries, Denmark and Germany for instance. Fig. 19 shows a projection by the Shell company of substantial growth in energy production and use by the year 2060, but with the global use of fossil fuel down to 2000 levels and over two thirds of the energy sources being non fossil fuel.
How about the cost of action to mitigate global warming, in particular to stabilise carbon dioxide concentration in the atmosphere as required by the FCCC and so to stabilise climate?
Studies by economists suggest that, providing the action is phased over, say, 20-50 years in a sensible manner, for instance to take account of the normal timescale for infrastructure replacement, the cost of stabilising carbon dioxide at say 400-500 ppm would be, on average, less than 1% of countries' GNP. This is substantially less than estimates I mentioned earlier of the economic cost of the damage if we do nothing, even if the unquantifiable damages are ignored.