Reducing Greenhouse Gas Emissions

Viscount Hanworth Excerpts

Thursday 2nd May 2019 Lords Chamber

[Viscount Hanworth (Lab)]

My Lords, in preparing for today’s debate, I looked at the text of a lecture on the subject of the atmosphere and the threat of global warming that I delivered exactly 25 years ago, and which remains on my academic website. It does not seem to be out of date, for the reason that, by 1994, the science of global warming was well established. However, there were uncertainties about the speed of the onset of the process of global warming and its liability to be accelerated through feedback effects. One of those feedback effects is due to the melting of polar ice. It was uncertain how rapidly melting would proceed. Bare seawater is much more absorptive of radiation than are ice and snow, and their melting would serve to accelerate the process of global warming, but to an unknown extent. The melting of the permafrost releases large quantities of methane gas, which has a far greater warming effect than carbon dioxide; this will also serve to accelerate global warming. Photosynthesis, which captures carbon dioxide, and biological decay, which emits it, are both enhanced by warming, but it was uncertain which of these would advance more rapidly. However, the destruction of forests has proceeded at pace, which has reduced the rate of carbon sequestration.

A further reason for the uncertainties was the difficulty in predicting the human response to the crisis of global warming in its various phases. I asserted that the crisis, which was then presently threatened, would become imminent at some stage and then, in a short time, become actual. The nature of the human response would depend to some extent on the duration of these phases. The feedback processes have proved stronger than was widely imagined, and the human response has been much weaker, and the crisis has indeed become actual sooner than one might have imagined.

At the time, there was some optimism that effective action would be taken to staunch carbon dioxide emissions, but these have grown steadily. In 1994, the atmospheric concentration of CO₂ was less than 360 parts per million by volume. The emissions are following an exponential trend and, today, the concentration exceeds 400 parts per million. Ice core data suggest that the pre-industrial concentration was perhaps 275 parts per million. The ultimate effect of the present levels is bound to be disastrous. The eventual levels may be much higher.

The main reason for the increased burden of atmospheric carbon dioxide has been the advance of manufacturing and the increasing adoption of western lifestyles in the developing economies of Asia. American emissions have been largely unchecked, while in some European countries, such as the UK, they have declined slightly. We have passed rapidly from the era of recognition, when warnings were widely broadcast and timely action to avert a climate catastrophe was first called for, to the present era, which could be described as the age of reckoning, when the catastrophe is upon us. We have squandered our early opportunities and must now act with extreme urgency.

This country has achieved much less in reducing its carbon expenditure than many of us might imagine. It is true that, in generating electricity, we have largely replaced our coal-fired power stations with gas-fired plants and wind farms. Also, our total consumption of electricity is slightly less than it was in the 1980s. These developments have been enabled in the UK by an ongoing process of deindustrialisation. However, if we reckon the carbon costs of what we consume, these have not been reduced. Much of what we consume is now manufactured in countries in which carbon emissions have grown rapidly; other noble Lords, including the noble Lord, Lord Whitty, made that point. Moreover, the climate change committee tells us that we are liable to miss the targets for the reduction of our domestic carbon emissions that were cast in legislation.

How should we react to these circumstances? I will describe three plausible reactions. The first is to adopt a counsel of despair. Our own carbon consumption must seem insignificant in relation to the global total. It can be asserted that our efforts at self-restraint in our emissions cannot have much of a global effect, that they cannot be to our advantage and that they will allow others to act with less restraint. I reject this outlook.

A second and more moral stance is to pursue the course of self-restraint with renewed vigour. It has been proposed that we should seek to exploit renewable sources of power—wind and sun—with increased determination, while enhancing the efficiency of our uses of energy. We should curtail our use of personal transport and insulate our houses. I support these nostrums of parsimony and abstemiousness. However, the difficulty with such a program of austerity is that it would be unlikely to afford us sufficient margins of additional power with which to pursue the electrification of heating and transport, which will be the key to further reductions in our emissions.

The third recommendation is that we should pursue, with the utmost vigour, a technological revolution in the generation and use of electrical power to produce a plenitude that would allow us to supplant all other sources of power. To achieve this, we need to build more nuclear power stations. The surplus power from these stations, which would occur at certain times if they are run at a constant level, should be used to generate hydrogen by electrolysis. The hydrogen would be a source of power in times of high demand for electricity. It should also be available for use in the fuel cells that should power our public and private transport. This technological revolution—the pursuit of which will demand courage—is liable to create a thriving economy, which should be capable of exporting to the rest of the world its solutions for confronting the scourge of global warming.