If we are lucky, 100 months from the beginning of August 2008, and based on a quite conservative estimate, we could reach a tipping point for the beginnings of runaway climate change (Simms, 2008).
The concentration of carbon dioxide in the atmosphere today, the most prevalent anthropogenic greenhouse gas, is the highest it has been for the past 650,000 years. In the space of just 250 years, as a result of the coal-fired
Industrial Revolution, and changes to land use, such as the growth of cities and the felling of forests, we have released, cumulatively, more than 1800 billion tonnes of carbon dioxide into the atmosphere. Currently, approximately 1000 tonnes of carbon dioxide is released into the Earth's atmosphere every second due to human activity. This is a figure that compares perversely to the fact that, during the first six months of 2008, the three fossil fuel companies BP, Centrica and Shell made the equivalent of UK£1000 profit every second (Lucas, 2008).
Greenhouse gases trap incoming solar radiation, warming the atmosphere. When these gases accumulate beyond a certain level - often termed a 'tipping point' - global warming will accelerate, potentially beyond control. A reasonable interpretation of precaution, in this case, would be to stay on the right side of that tipping point.
In climate change, a number of feedback loops amplify warming through physical processes that are either triggered by the initial warming itself, or the increase in greenhouse gases. One example is the melting of ice sheets. The loss of ice cover reduces the ability of the Earth's surface to reflect heat and, by revealing darker surfaces, increases the amount of heat absorbed. Other dynamics include the decreasing ability of oceans to absorb carbon dioxide due to higher wind strengths linked to climate change. This has already been observed in the Southern Ocean and North Atlantic, increasing the amount of carbon dioxide in the atmosphere and adding to climate change.
Because of such self-reinforcing positive feedbacks (which, because of the accidental humour of science, we must remind ourselves are, in fact, very negative), once a critical greenhouse concentration threshold is passed, global warming will continue even if we stop releasing additional greenhouse gases into the atmosphere. If that happens, the Earth's climate will shift into another more volatile state, with different ocean circulation, wind and rainfall patterns, the implications of which, according to a growing litany of research, are potentially catastrophic for life on Earth. Such a change in the state of the climate system is often referred to as irreversible climate change.
So, how exactly do we arrive at the ticking clock that takes us in 100 months from the summer of 2008 to the end of 2016? It is possible to estimate the length of time it will take to reach a tipping point. To do so you combine current greenhouse gas concentrations with the best estimates for the rates at which emissions are growing, the maximum concentration of greenhouse gases allowable to forestall potentially irreversible changes to the climate system, and the effect of those environmental feedbacks.
To make a reasonable, if cautious, estimate, it is possible to follow the latest data and trends for carbon dioxide, making allowances for all human interferences that influence temperatures, both those with warming and cooling effects. This estimate also follows the judgements of the mainstream climate science community, represented by the Intergovernmental Panel on Climate Change (IPCC), on what it will take to retain a good chance of not crossing the critical threshold of the Earth's average surface temperature rising by 2°C above pre-industrial levels. Even this steady approach, however, is perhaps too optimistic. Why? Because a rise of 2°C may mask big problems that begin at a lower level of warming. For example, collapse of the Greenland ice sheet is more than likely to be triggered by a local warming of 2.7°C, which could correspond to a global mean temperature increase of 2°C or less, and lead, over time, to a sea-level rise of up to 7m (IPCC, 2007).
Given all of the above, by the end of 2016 we stand to reach a concentration of greenhouse gases at which it is no longer 'likely' that we will stay below the 2°C temperature rise threshold. 'Likely' in this context refers to the definition of risk used by the IPCC. However, even just before that point, there is still a one third chance of crossing the line. Action, then, is more than urgent (IPCC,
We already know that people living in poverty are hit first and worst by global warming. This and the challenge of reducing poverty in a carbon-constrained world calls for a new development model that is both climate proof and climate friendly. From now on, all decisions will need to be scrutinized for whether they will increase or decrease vulnerability to climate change. We must look through the lenses of building resilience at the community level and reducing risk. And, it is the communities at risk who must shape our plans.
Parallel to the approach of the IPCC, the 2008 report of the International Assessment of Agricultural Knowledge, Science and Technology (IAASTD,
2008) showed that a massive shift of support to small-scale farmers using a diverse range of agro-ecological methods would be one of the most efficient ways to build resilience, inoculate against food crises and ensure against increasingly hostile weather patterns. Community-based coping strategies such as the use of seed banks, water management, vulnerability mapping, storm and flood protection that works with the local environment, and the conservation of forests and other ecosystems all represent effective ways for threatened communities to adapt.
If replicated and scaled up, small-scale renewable energy projects promoted by governments and community groups can help both to tackle poverty and reduce climate change. But this needs political commitment, significant new funds from governments and a major shift in priorities for energy lending by the World Bank and other development bodies. There is no either/or approach possible; the world must meet both its commitments to achieve the MDGs and tackle climate change. The two are inextricably linked.
Here we crash headlong into another equally large problem. It is clear that conventional economic growth will happen in poor countries as a consequence of effective poverty reduction. But at a global level, the policies designed to pursue growth have become a mask for making the rich richer, while leaving the poor with few benefits and abandoned to deal with growth's environmental consequences. During the 1980s, often referred to as the lost decade of development, for every US$100 worth of global economic growth, around US$2.20 (Simms and Woodward, 2006) found its way to people living below the absolute poverty line. A decade later that had shrunk to just US$0.60, and the actual mean income of those living under US$1 per day in Africa also fell (Chen and Ravallion, 2004).
There has been, in effect, a sort of 'flood up' of wealth from poor to rich, rather than a 'trickle down'. It means, perversely, that for the poor to get slightly less poor, the rich have to get very much richer, implying patterns of consumption that, in a world facing climate change, cannot be sustained. It now takes around US$166 worth of global growth (made up of all those energy-hungry giant flat screen TVs and sports utility vehicles) to generate a single dollar of poverty reduction for people in absolute poverty, compared with just US$45 in the 1980s. Earnings of between US$3 and US$4 per day are the approximate level at which the strong link between income and life expectancy breaks down. So, let us ask what would happen if we agreed US$3 per day as the minimum level of income to escape absolute poverty (Simms and Woodward, 2006).
Using the ecological footprint measure,4 if the whole world wished to consume at the level of the US - a consumption pattern that has been fuelled, incidentally, by the credit binge that led to the current economic crisis - we would need, conservatively, over five planets like Earth to support us. But under the current pattern of unequally distributed benefits from growth, to lift everyone in the world onto a modest US$3 per day would require the resources of around 15 planets like ours. Where, you might ask, will the other 14 come from?
To tackle poverty in a carbon-constrained world we need a new development model, based on better measures of progress and a shift from relying on unequal global growth to serious redistribution. If we think of the planet as a cake, we can slice it differently; but we surely cannot bake a new one. Climate change is not the only reason that we have to learn to live with far fewer fossil fuels. Development must also contend with the volatility of oil prices, which reached record highs in 2008 and will probably return there as the world moves out of recession and the imminent global peak and long decline of oil production.
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