Gordon Brown’s assumptions on climate change

By: Icecap.us
By: Icecap.us

On 19th October, Gordon Brown made a high-profile speech on climate change policy to the Major Economies Forum in London. As a lead-in to the Copenhagen conference in December, this was widely reported in terms such as ‘50 days to save the world’. Of course, the Prime Minister did not exactly say that, but headline writers did not have to get too carried away to derive this from the actual statement: ‘In every era there are one or two moments when nations come together and reach agreements that make history because they change the course of history, and Copenhagen must be such a time. There are now fewer than 50 days to set the course for the next few decades, so as we convene here we carry great responsibilities, and the world is watching.’

In the language of international summitry, this is still pretty eye-catching, so it is perhaps interesting to analyse some of the rest of the speech, which makes the case for how vital it is to reach an agreement in Copenhagen.

‘If we do not reach a deal over the next few months, let us be in no doubt, since once the damage from unchecked emissions growth is done, no retrospective global agreement in some future period can undo that choice. By then it will be irretrievably too late, so we should never allow ourselves to lose sight of the catastrophe we face if present warming trends continue.’
This statement takes it as read that the assumptions on which the various climate models are built are unquestionably right. In reality, the key assumption in all of the models is that there is a positive feedback mechanism which enhances the actual relatively modest warming effect of additional atmospheric carbon dioxide. This is by no means proven, and there are equally plausible hypotheses which suggest that negative feedback mechanisms dominate. The reference to ‘present warming trend’ is also misleading. It is now generally accepted that there has been no warming for a decade. There is indeed a positive warming trend if the starting point is taken as the mid-70s, but this is far less evident if the baseline is the mid-30s. Trends depend on start and end points.

‘Only last week we saw new evidence of the rapid loss of Arctic Sea ice.’
Another misleading statement. Arctic sea ice varies to a very large extent from season to season. 2007 saw the largest summer loss in recent times, but 2008 was less extreme, and 2009 saw greater coverage again. Even the real drivers of these changes are not known, despite the glib assertions that the Arctic ice is sure evidence of human interference with the climate. Almost certainly ocean currents, wind patterns and sea temperature have a greater impact than air temperatures, and there is no clear evidence that any changes are driven primarily by carbon dioxide levels.

‘In just 25 years the glaciers in the Himalayas, which provide water for three-quarters of a billion people could disappear entirely. IPCC estimates tell us now that by 2080 an extra 1.8 billion people - equal to a quarter of the world�s current population - could be living and dying without enough water.’
Note the use of the conditional: ‘could’. This estimate comes from models using recent measurements for melt rate and precipitation together with assumptions for future emissions and consequent direct effects on surface temperatures and indirect effects on weather patterns. This is a worst case scenario, reliant on the all-important positive feedback assumption. There are already far too many people living with inadequate water supplies, because of low average rainfall, inadequate capture and storage facilities for intermittent rainfall or, as is the case in southern Africa, a pattern of periodic droughts. The possible contribution of climate change to this is unknown, but investment in water storage infrastructure could do a lot to alleviate this.

‘If the international community does nothing to assist the rainforest nations in protecting the world�s rainforests, the damage not just to climate but to biodiversity, to watersheds and to the livelihoods of millions of people will, as you know here, be incalculable.’
Deforestation can have a very significant effect on local or regional climate, as must certainly have been the case for prehistoric Europe as forests were cleared for farmland. In the case of tropical forests, there would also be a large negative impact on biodiversity. Current livelihoods would certainly be lost, but probably there would be many farming-related jobs created. Such wholesale changes would be regrettable, but the impact on global climate is still unclear: there is still debate about the carbon cycle and patterns of absorption and emission of carbon dioxide and methane from forests.

‘And the recent report of the Global Humanitarian Forum led by Kofi Annan suggests that 325 million people are already seriously affected by drought, disease, floods, loss of livestock, low agricultural yields and decline of fish stocks. A further 500 million are at extreme risk, and every year the effects of climate change are already killing 300,000 people, the numbers killed by Indian Ocean tsunami, and the toll could rise to 500,000 each year by 2030.’
This report has been widely criticised for the assumptions it makes and the conclusions drawn. In particular, the figure of 300,000 people killed by the effects of climate change has not been justified, and appears to have been an extreme estimate produced for political purposes. It is difficult to take anything else in the report seriously in view of its evident bias and subjectivity.

‘On Saturday, the President of the Maldives, whose concerns I share, held a Cabinet Meeting underwater to highlight the calamity that may engulf his islands. In the South Pacific nation of Kiribati, President Tong has requested international aid to evacuate his people before their land quite literally disappears.’
There is no evidence that the rate of sea level rise in the Pacific or elsewhere has increased in recent years from the fairly steady level apparent over the last century. Low-lying small island nations such as the Maldives and Kiribati are made up of a series of coral atolls, which are continually being eroded by wind and waves while new coral is being added. They appear historically to have been at about the same elevation above sea level as the waters have slowly risen. In short, although there are undoubtedly problems associated with population density and water extraction on the Maldives and elsewhere, there is no reason to suppose that the environment is any more vulnerable than it was a few decades ago. Publicity stunts such as the underwater Cabinet meeting may grab headlines, but they do not change the facts.

‘The extraordinary summer heat-wave of 2003 in Europe resulted in 35,000 extra deaths. On current trends such an event could become quite routine in Britain in just a few decades’ time. And within the lifetime of our children and grandchildren the intense temperatures of 2003 could become the average temperatures experienced throughout much of Europe.’
Despite attempts to draw parallels between extreme weather events and future weather patterns, such projections, we should remember, are based on incomplete computer models which all make essentially the same assumptions about the enhanced greenhouse effect, and which clearly deal in an inadequate way with the natural drivers of climate which have been dominant for at least the last decade.

In contrast to what he sees as the unsustainable and insecure path of ‘business as usual’, the Prime Minister extols the virtues of a decarbonised energy system: ‘Now, the other path leads to a low-carbon, high-cooperation future; a future too of economic growth, but growth powered by new energy sources and by energy efficiency, and bringing with it huge economic opportunities for developed and developing countries alike: new jobs and businesses; new technologies; new export opportunities.’

To many, this Brave New World probably sounds little different to what would happen anyway without specific policies to reduce greenhouse gas emissions. As fossil fuel prices rise, the incentive to use alternative energy supplies grows. At the same time, innovation makes some new technologies increasingly competitive so that their widespread adoption becomes an obvious choice. Which will be the winners in a generation’s time we simply do not know, but winners there will most certainly be.

In the meantime, if the arguments by political leaders for a binding post-Kyoto agreement in Copenhagen are based on such uncertain evidence as quoted by Gordon Brown, perhaps we would be better advised to take the business as usual path. Business as usual does not mean doing the same thing for ever, but innovating and progressing in the way that we and previous generations have done.

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