Nigel Lawson and others are suggesting that temperatures have ‘stabilised’ since the late nineties. 1998 saw the highest global average temperature and only 2005 has closely matched it. Since no year since 1998 has exceeded the record, some commentators are saying the global warming has stopped. The implication, sometimes stated, sometimes not, is that the increasing rate of growth of CO2 concentration is having no effect on temperature.
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The Heartland Institute, a US free-market think tank, held a conference on climate change in New York in early March. It was a forum for some of the climate change sceptics to discuss their research. The conference got very little coverage in the media and was ignored by the science pages of the newspapers.
This seems a mistake. A large section of the population of the US and the UK, and smaller numbers elsewhere, believe that the apparent scientific consensus on global warming is a result of selective coverage by TV and press. The failure to cover presentations by some of the leading sceptics is support for the accusation that global media, and mainstream climate scientists, are refusing to engage with the dissenting views of reputable scientists who do not share the standard view.
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| Switchgrass biofuel crop |
Will next-generation biofuels have a less destructive effect on agriculture? A study just published by US government scientists suggests that so-called ‘cellulosic’ ethanol has much better energy balance than today’s biofuels.[1] By energy balance, we mean the energy used to make the fuel compared to its energy value when burnt in a car’s engine. News summaries of the paper’s contents focused on one estimate that suggested that to make cellulosic biofuels might only need 6% of the energy value contained in the fuel. Depending on which crop is used, where it is grown, and how it is refined, most of today’s biofuels have only a weakly positive energy balance. So the paper gives hope that we might expect considerable progress towards carbon-neutral transport fuels when we can start refining all vegetable matter, not just foodstuffs, into fuels.
Cellulosic biofuels may well become important sources of motor fuels. There is certainly huge amounts of money flowing into the field. Unfortunately none of the news articles covering the US research pointed out the technology for turning cellulose into fuel is still a long way from commercial viability. Yes, we can turn grass into ethanol, but at prices which will double the price of petrol. And the greenhouse gas savings will almost certainly not be as attractive as the paper suggests, not least because the authors did not include the serious impact of nitrous oxide emissions from fertilised fields.
Carbon dioxide levels in the atmosphere rise by about 2-3 parts per million every year and the rate is slowly increasing. As well as this upward trend, there is an annual cycle: carbon dioxide levels fall in the northern hemisphere summer and rise strongly in the winter. The reason is that most of the vegetated land area is in the northern hemisphere and during the northern summer plants and trees absorb CO2.One effect of increasing spring and autumn temperatures has been to increase the length of what is loosely called ‘the growing season’. Plant growth can start earlier in spring and can continue until later. It might be thought that this would help vegetation take up more CO2, acting as a counterweight to increased fossil fuel use.
Research published in Nature in early January very strongly suggests that this is not happening. Warmer autumns are associated with a bringing forward of the date at which plants start losing CO2, not the reverse. Higher spring and autumn temperatures are tending to decrease the length of the period each year in which northern hemisphere plants are taking up carbon. If this research is confirmed, this is yet another potential positive feedback because higher temperatures might diminish the ability of biomass to take up carbon.
The IPCC released a 23-page report summarising the work of the fourth phase. Newspaper headlines suggested the document was more apocalyptic than the third summary of 2001. The reality is more complex.
CO2 output is accelerating, the ocean and land sinks are getting less effective at absorbing it. So the rate of growth of carbon dioxide in the atmosphere is increasing.
(Canadell, Le Quéré, and others, ‘Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks’, Proceedings of the National Academy of Sciences, 25 October 2007; URL: http://tinyurl.com/yqew8o [accessed 27 October 2007].)
The pre-industrial CO2 concentration in the atmosphere was about 280 parts per million. It was 381ppm in 2006. The growth rate between 2000 and 2006 was 1.93ppm, a significant increase on growth rates in earlier periods. Many policy-makers see it as vital to keep below concentrations of about 400ppm of CO2. The increase in the rate of rise of CO2 makes the achievement of this target more difficult.
Increases in the amount of CO2 in the atmosphere reflect the volume of global emissions and the effectiveness of the oceans and land mass in absorbing greenhouse gases. This paper contains evidence both that emissions growth is speeding up and that the greenhouse gas sinks are capturing less CO2.
The growth rate in emissions between 2000 and 2006 was 3.3% a year compared to 1.3% in the 1990s (please see the article on Chinese exports in this issue of Carbon Commentary for corroboration of this finding). This increase reflects fast economic growth, particularly in China and India and a worrying increase in the amount of CO2 produced per unit of global output. It cannot be stressed enough that this second cause of emissions growth is unexpected. We thought we were going to see energy use fall in relation to economic output.
By contrast, models have predicted a decline in the effectiveness of ocean CO2 ‘sinks’. This paper shows that we can have a strong suspicion (but not near certainty) that this process has started. The authors point to increasing wind speeds in the Southern Ocean as a primary cause. This turbulence ‘ventilates’ the carbon dioxide contained in the surface of the sea. Droughts in mid-latitude regions have contributed to the decreased efficiency of land absorption.
The paper concludes that – with large margins of error – economic growth generated 65% of the increase in atmospheric CO2; the decrease in the efficiency of the sinks generated another 18% and caused a rise in the carbon output required to generate a dollar of world GDP.
The authors summarise by saying that their results ‘characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing’.
Bjørn Lomborg, a professor at Copenhagen Business School, is the most formidable critic of those who think that cutting climate-changing gases is the most important problem the world faces. He made his name with ‘The Skeptical Environmentalist’ and his new book continues his drive to get the world to see global warming as just one of the world’s important problems.
Lomborg believes climate change is happening, and that mankind’s activities are responsible. But he tells that we shouldn’t do much about global warming because the costs are very high and the benefits are limited and far-off. Like most books written by partisans in this impassioned debate, much of what he says can be questioned.
Nevertheless, this is an extremely valuable polemic: it stresses repeatedly that taking action to stop climate change may have very high short-term costs. If by clumsy attempts to hold down emissions we stunt the prospects for global economic growth, we may do more harm to the world’s poor than would be inflicted by climate change. It needs to be said time and time again that disease and malnutrition are killing far more people today than climate change. We are making progress diminishing the impact of these scourges. Despite what you sometimes read in the newspapers, world food supply and life expectancy are improving. Panic-stricken action on climate change must not be allowed to halt this progress. We need a rational assessment of whether it is best to spend money on slowing climate change or to whether we would achieve better effects from focusing resources elsewhere.
Bjørn Lomborg is an able debater with a passionate interest in his subject. But he overstates his case, focuses on only parts of the issue and avoids any discussion of a possible future acceleration of global warming. Even with these weaknesses Cool It needs to be part of the continuing debate on how to respond to the climate threat without crippling the poorest economies of the world.
Many agricultural crops can be turned into fuels. Diesel substitutes can be made from the oil in seeds. The sugars in cereals and tubers can be fermented into ethanol.
At first examination, biofuels look as though they might significantly reduce carbon emissions. An agricultural crop takes carbon from the air through the photosynthesis process. When the harvest is processed, and the output used as a fuel, the carbon returns to the atmosphere. Proponents sometimes said that agricultural crops make ‘carbon-neutral’ fuels.
Over the last two years, this simple optimism has been eroded. Two further blows have fallen in recent weeks:
- Nobel winner Paul Crutzen and his team showed that we may have been underestimating greenhouse gas emissions from using fertiliser. The work suggested that emissions of nitrous oxide may be far higher than previously thought.
- Richard Doornbusch, who is attached the OECD, wrote a paper which said: ‘The conclusion must be that the potential of the current technologies of choice – ethanol and biodiesel – to deliver a major contribution to the energy demands of the transport sector without compromising food prices and the environment is very limited.’
The balance of evidence is that biofuels produced from crops grown in temperate climates save very small amounts of emissions. Moreover, the land used for biofuel crops could be used for food or biomass for energy. In tropical lands, biofuel crops may save carbon emissions. But the energy policies of richer countries may be incentivising tropical farmers to cut down forest to grow fuel crops. The effect of this almost certainly outweighs any emissions reductions.
Despite the increasingly prevalent view that biofuels are little or no improvement on fossil fuels, both the EU and the US are obliging retailers to increase the percentage of motor fuels derived from agricultural sources. This is a mistake.
The Advertising Standards Authority is struggling to hold the line on the advertising of environmental benefits. In June, the Authority put out a series of instructions trying to impose clearer conditions on advertisers. But it continues to have to adjudicate on a series of difficult decisions. Last week saw a wind power developer taken to task for over-estimating the carbon savings from turbines. The Authority had to decide which type of power station would produce less power as a result of a new wind farm – coal or gas. It took advice from the National Grid and proceeded to tick npower off, even though the power company was following rules previously set down by the ASA itself.
In at least one other country, the advertising regulator has thrown in the towel and told some advertisers simply to stop advertising green claims. Reuters reports that Norway’s Consumer Ombudsman has told car advertisers that ‘We ask that…phrases such as “environmentally friendly”, “green”, “clean”, “environmental car”, “natural” or similar descriptions not be used in marketing cars.’
We cannot be far away from this sort of rule in the UK. Green claims are almost invariably contentious and difficult to prove. We simply don’t have an accounting system that can deal yet with carbon. Advertisers are going to be forced to avoid any but the most clear-cut and well-documented savings.
Some scientists think that the world’s halting attempts to reduce carbon emissions are bound to fail. So they have proposed various schemes for counteracting the global warming impact of fossil fuels. The Gaia scientist James Lovelock proposed an unusual and untested idea in a recent paper. He suggested that we install millions of pipes to bring nutrient-rich water to the surface to feed carbon sequestering organisms. Other scientists are working on schemes as diverse as mirrors that reflect part of the sun’s energy, increased aerosol pollution to stop sunlight getting to the earth, and improving plankton growth by adding iron to the oceans.
All these schemes are ‘offsets’; they seek to counter-balance the impact of human activities with schemes to reduce CO2 elsewhere. The technology optimists believe that one or more of these techniques can completely counteract human effects. The cost often seems very reasonable – in the billions rather than the trillions – and the technological challenges seem not insuperable. The pessimists say these schemes will have huge unintended effects, possibly worse than climate change itself, and that toying with ‘geo-engineering’ projects, as they are called, simply delays the day that the world starts to realise it must cut fossil fuel use. Geo-engineering deals with the symptoms, not the causes, of global warming. And none of the proposed schemes deal with the adverse effects of higher CO2 concentrations, such as increased ocean acidity.
This article argues that all the major geo-engineering proposals have substantial pitfalls, but that it makes clear sense to increase the research funding into these schemes. The opponents and proponents of geo-engineering have got locked into an almost theological debate as to the ethics of climate modification but this argument should be secondary to the need to have well-defined back-up plans in the event of increasingly rapid deterioration of the global climate.
Photo: the glacier at Ilulassit in Western Greenland
In early September, leaders from the major faiths came together in Greenland to pray for the future of the planet. They may well have chosen Greenland because of the visible and deeply worrying changes in the glaciers and ice fields that cover almost all its vast area. The melting of the ice sheet has speeded up dramatically since 2000.
The state of Greenland’s glaciers is critical to the rate of global sea level rise. A complete melting of the island’s ice would raise water levels by about 7 metres, enough to flood much of the world’s inhabited land. To give one example, 15% of Bangladesh’s population would be displaced by a rise of just 1.5 metres. Almost all the country’s habitable land would disappear if the water level rises by 7m.
The religious leaders went to the town of Ilulissat on Greenland’s western coast. Here a rapidly retreating glacier calves icebergs into a fjord at a rate of 35bn tonnes of water a year. The daily water loss would provide all the water London or New York needs for a year. Estimates suggest that between 6.5% and 10% of all the ice flowing off the interior icefields of Greenland melts into this fjord. This means that the increase in the rate of melt of this one glacier is adding about 0.06mm a year to the global sea level, 4% of the rate of rise during the 20th century.
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