IT’S DIFFICULT to have a cool-headed debate about global warming. At a psychological level, the sheer scale of the issue – global, long-term, complex, threatening – tends to induce either paralysing despair or wilful ignorance. It doesn’t help that many protagonists in the debate, whether environmental NGOs or climate sceptics, bring with them all-too-obvious ideological baggage. In the United States, indeed, the notion that impartial evidence might assist judgement has been almost entirely abandoned now that climate change has become embroiled in the culture wars between the new conservative movement and its Democratic opponents.
So, as Professor Ross Garnaut unveils the update to his landmark report on Australia’s role in eight tantalising instalments and the federal government names a date for a price on carbon, it might be useful to take stock of where we are.
Debate about climate change rests on three pillars of evidence. On one corner is the science – the evidence on whether human-caused warming is taking place, and the effects it will have. On another are the emissions – how big they are now, and what their future trajectory will be given the targets countries have set. And on the third is the investment – the evidence of what is actually happening on the ground to cause emissions to grow or decline.
First, the science. Despite the ferocious attack on the validity of climate science waged by the sceptics over the past two years, the striking conclusion one reaches from surveying the debate is that the balance of evidence hasn’t actually changed at all. It remains the case that the overwhelming majority of scientific work published in the field reinforces the extreme likelihood that the warming which the world is currently experiencing (the eleven warmest years on record have all occurred since 1998) is caused by human activity, and that, if this warming proceeds unchecked towards average temperature rises of 4–7 degrees Celsius, its impact on ecosystems, natural resources and human society will be deeply traumatic over the next century or so.
In fact, far from undermining these conclusions, most of the new evidence produced over the last two years suggests that the risks may be greater than previously thought. The recent revelation in the journal Science that last year’s drought in the Amazon is likely to have caused the rainforest to emit more carbon dioxide than it absorbed – and that this formerly “once in a hundred year event” has now happened twice in six years – provides a dramatic example of the phenomenon of “positive feedback” that is now perhaps the single most important focus of climate research. Positive feedback occurs when warming has effects that, in turn, speed up the warming process. (The Amazon droughts are believed to have been caused by higher surface temperatures in the tropical Atlantic.) The accelerated melting of Arctic summer ice over the last few years, which reduces the reflection of solar radiation and therefore further increases temperatures, provides another example.
The core of the sceptic case has been that there is greater uncertainty about the causes and impacts of warming than climate change protagonists have allowed. But the case for taking action to reduce emissions has never rested on certainty. As Garnaut argues, the rationale is insurance. Given the very strong likelihood that warming is caused by rapidly rising greenhouse gas emissions, it is sensible for society to seek to prevent catastrophic outcomes by reducing those emissions. The chances of being burgled do not have to be 100 per cent (or even a tenth of that) for households to install window locks and alarms. The significance of the Queensland floods and Cyclone Yasi are therefore not that these events are evidence of global warming – one-off events can never be so ascribed – but that they indicate the huge human and economic costs of the kinds of impacts that warming is predicted to cause more often. The question that society is being asked is simple: are we willing to pay now to reduce the future frequency of such events – along with the more pervasive projected impacts on water, ecosystems and agriculture? The argument that we would be better spending money to adapt to such change than to mitigate it makes little sense in this context. Without action to reduce emissions growth, warming will be much greater, and its costs far higher. So adaptation and mitigation are not alternatives: mitigation is a way of reducing the costs of adaption.
The challenge posed to climate science by the sceptics has been widely taken up within the media. But it is noteworthy that only in the United States, Canada and Australia have the sceptics’ arguments weakened governments’ resolve to act on climate change. Elsewhere, including in the developing world, mainstream climate science remains overwhelmingly accepted by governments and parliaments, and commitments to act have remained largely intact even under the intense economic pressures of the last two years.
WHICH brings us to the second pillar. What do we know about the current level of global greenhouse gas emissions and – given government policies around the world – their likely trends over the next decade? Over the past two years, according to recent estimates from the US Energy Information Administration, carbon dioxide emissions from energy use in developed countries have plummeted as a result of the recession – down 7 per cent in 2009 in the United States, Europe and Russia, and nearly 10 per cent in Japan (though less than 2 per cent in Australia). Yet the sobering fact is that, despite this, overall global energy emissions were more or less the same in 2009 as in 2008. The developed world’s recession was almost entirely cancelled out by the undiminished growth in emissions from China (up 13 per cent) and India (up 9 per cent).
The figures highlight the new reality of climate change: while historic responsibility for the problem lies with the developed economies, from now on almost all the growth in emissions will come from the developing world, with China not merely having become the world’s largest current carbon polluter but also growing more rapidly than anywhere else.
But this focuses attention on future projections rather than the current snapshot. Do current trends offer any hope that emissions are being curbed? A new report published by the United Nations Environment Programme, or UNEP, provides a helpful analysis. Taking ranges of probability from a number of different climate and economic models, it sets out different “pathways” or trajectories for global emissions which would be likely (with a 66 per cent or more chance) to hold the global average temperature rise below the UN goal of 2 degrees Celsius. The report then analyses the targets and policies that countries have adopted to curb their emissions over the period to 2020. It seeks to discover if there is an “emissions gap” between the trends to which countries are now committed and the possible pathways to 2 degrees.
It’s worth recalling that the goal of keeping warming to no more that 2 degrees above pre-industrial temperatures does not mean that 2 degrees is some kind of threshold above which climate change suddenly becomes more dangerous. Our understanding of climate impacts is not precise enough to say that a rise of (say) 2.3 degrees would be catastrophic. The point, rather, lies in the risk that the climate behaves not according to the central estimates of the models but in line with the outer projections. Emissions pathways which have a 50 per cent probability of achieving 2 degrees are very unlikely (a probability of 5 per cent) to lead to warming of 3 degrees or more. But emissions pathways which have a 50 per cent chance of hitting 2.3 degrees are three times as likely (15 per cent) to lead to a 3 degree rise. So the UN goal is in reality not “no more than 2 degrees of warming.” It is “emissions pathways which are likely to achieve no more than 2 degrees of warming” – because these are the pathways which reduce the risk that in fact much greater warming will occur.
The UNEP analysis has the great advantage of clarity. Global emissions in 2005 were around 45 Gt (gigatonnes) of “carbon dioxide equivalent” (the metric which includes all the different greenhouse gases). To be likely to hold temperature rises to 2 degrees, emissions will need to be in the range of 15–19 Gt per year by 2050 – a cut of well over half. To achieve this, emissions can take a number of different pathways, all of which require global emissions to peak by 2015–20. The higher the peak, and the later it occurs, the faster the required reduction in emissions between 2020 and 2050. Taking median figures, the UNEP report suggests that by 2020 global emissions will have to be no more than 44 Gt of carbon dioxide equivalent, and emissions will have to be cut by around 3 per cent each year thereafter to 2050.
So how do current trends and commitments match up to this? Well, there’s good news and bad. The good news is that since the 2009 UN climate conference in Copenhagen – and confirmed in December in Cancun – all the major economies of the world have made commitments to reduce either their absolute emissions or their rate of growth. To many people’s surprise, the most radical commitments have been made by the developing countries. China’s target of improving the “emissions intensity” of its economy (its emissions per unit of GDP) by 40–45 per cent by 2020 will involve a very substantial decoupling of emissions from growth. The same is true of Brazil’s commitment to cut its emissions growth by up to 39 per cent below expected trends by 2020, largely by limiting deforestation. India, Indonesia, South Africa, Mexico, South Korea and others have made similar kinds of pledges. Meanwhile the European Union is committed to cutting its absolute emissions by 20–30 per cent on 1990 levels by 2020, Japan by up to 25 per cent, and the United States by 4 per cent (which, because of the recession, could yet be within reach, even without formal climate legislation). Australia’s range remains officially 5–25 per cent below 2000 levels – though no one now believes that the upper end is politically feasible.
And therein lies the bad news. For these pledges and targets do not, in fact, add up to 44 Gt in 2020, as the 2 degrees pathways require. Indeed, many are highly conditional, either on what other countries do, or on receipt of financial support to developing countries. (Though note that both China and Brazil have eschewed financial help.) Moreover, the impact of the pledges will depend a lot on the rules under which national emissions are counted. So the UNEP report describes a number of possible scenarios. If countries cut emissions at the top of their ranges, and use strict accounting rules, global emissions in 2020 would be around 49 Gt – a significant cut of 7 Gt over what would happen in the absence of these policies, but still short of the “2 degrees” figure of 44 Gt. On the other hand, if countries go to the bottom of their pledges, and use lax accounting rules, emissions would be closer to 53 Gt, a much smaller cut over “business as usual,” and fully 9 Gt short of the goal. So the emissions gap between the 2 degrees goal to which countries have signed up, and the pledges they have actually made, is between 5 and 9 Gt in 2020.
Does this mean that 2 degrees is now impossible? No. The 2020 pledges could still be increased following the review which the UN agreed in Cancun for 2013–15. And then it depends on the rate at which emissions can be reduced after 2020. The models from which the UNEP analysis is taken assume a more or less uniform rate of annual emissions reduction. But it is not impossible that technological breakthroughs might occur over the next two decades which could considerably accelerate the decarbonisation trend. The mass penetration of electric cars within the next ten or fifteen years might be one possibility; a reduction in the cost of solar power to well below that of coal and gas could be another. It would be dangerous to assume we can rely on such rapid post-2020 emissions cuts; but their possibility ensures that 2 degrees is still a feasible (if very difficult) goal – so long as strengthened commitments for 2020 are implemented and the peak therefore occurs by then.
AND so to the third pillar. Political pledges and targets are all very well, but are they likely to be achieved? Is there any evidence now of changing patterns of energy investment such as to make governments’ 2020 promises believable?
Perhaps surprisingly, the answer is yes. Over the last three years, something rather dramatic has been happening in the world of global energy investment. For two hundred years, the world’s inexorable industrialisation has been powered by carbon-based energy – coal, oil and gas. But since 2008, more has been invested globally in renewable capacity than in fossil fuels. Research by analysts Bloomberg New Energy Finance reveals that in 2010 total investment in clean energy reached a record US$243 billion, more than double the level in 2005. The surge has occurred right across the renewable technologies – global spending on solar panels and other “distributed” renewables rose over 90 per cent in a single year, while wind power grew almost a third and the new technologies of smart grids, energy storage and electric cars by over a quarter. Significant government incentives allied to falling costs are driving this revolution.
Now we shouldn’t get carried away. China is powering this clean growth: in 2010 its investment in clean energy topped US$50 billion. But at the same time it also invests more than anyone else in fossil fuels, with a new coal-fired power station opening on average every week (though many are also being closed down). The oil industry continues its relentless search for new sources – at US$100 a barrel, extracting oil from the tar sands of Western Canada and exploring in the Arctic are looking highly attractive. And the sudden emergence in the United States of previously untapped “shale gas” (gas found in rock deposits) and the growth in the use of liquefied natural gas have created in the last year a world gas glut that will have a double-edged impact on other fuels. On the one hand new gas could displace coal in electricity generation, which would reduce overall emissions (gas is cleaner). On the other, as the International Energy Agency has warned, it could inhibit investment in renewables, which in the medium to long term would mean emissions stay on a much higher path.
So the investment picture is by no means simple. But the new ascendancy of renewables is without doubt highly significant. If bending the curve of global emissions is like trying to reverse a supertanker, it is not too much to conclude that the ship has now started its long U-turn. How quickly the manoeuvre can be performed, and how far the tanker will have travelled before it starts moving in the opposite direction, will determine the fate of the planet.
So what conclusions should we draw from our three pillars of evidence? I would suggest the following.
One, that the evidence on future climate change remains deeply alarming. The impacts of a warmer world will be huge and costly in both economic and human terms. So the insurance case for preventative action remains extremely strong.
Two, that such action is now beginning to happen, through major investment in clean energy. But this investment will need to continue its rapid growth over the next decade, requiring considerable government support, if emissions are to peak by 2020.
Three, that the political commitments countries have currently made are not enough to make it likely that temperature rises will be limited to 2 degrees Celsius. So if that goal is to be achieved, commitments will need to be increased for 2020 and strengthened thereafter.
Four, that it is difficult to see countries making stronger commitments of this kind unilaterally. Given the impact of trade competition and the problem of “free riding,” the community will need some kind of agreement to do more. The search for such agreement remains elusive. But it also remains necessary. •