The Case for a Risk-averse Response to Climate Change

This is Part 3 of the Climate Change: A post-Bali Agenda series

The question of how to tackle climate change straddles the boundaries between science, engineering, economics and policy-making, the most critical and sensitive of which being the interface between science and policy. Having examined the risks from a scientific angle it’s time to turn our attention to policy, and most importantly the risk of policy failure.

The traditional role of policy makers has been to recommend optimal strategies for achieving an objective, or set of objectives, within fixed set of boundaries. This approach fails when it comes to tackling climate change for several reasons. First and foremost, developing effective climate change policy is not about designing an optimal policy solution with a fixed and acceptable level of risk. It is about developing a set of policies for which the risk of failure is absolutely minimal, as the consequences of failure far outweigh the economic benefits of accepting that risk. However, this is further complicated by the fact that the boundaries for policy formation are not fixed, although fortunately there is the scientific consensus that they are highly unlikely to become less restrictive. As such the context for climate change policy formation is one where there should be an inherent expectation that the current boundaries will become more restrictive over time, most likely a short period of time, and therefore policy formation needs to be flexible enough to account for this and recommend strategies that allow for rapid responses to changes in the best available evidence.

These points were summed up in Pittock (2006):

"Uncertainties in climate change science are inevitably large, due both to inadequate scientific understanding and to uncertainties in human agency or behavior. Policies therefore must be based on risk management, that is, on consideration of the probability times the magnitude of any deleterious outcomes for different scenarios of human behavior. A responsible risk management approach demands that scientists describe and warn about seemingly extreme or alarming possibilities, for any given scenario of human behavior (such as greenhouse gas emissions), even if they appear to have a small probability of occurring. This is recognized in military planning and is commonplace in insurance. The object of policy-relevant advice must be to avoid unacceptable outcomes, not to determine (just) the (apparently) most likely outcome."

Pittock, B. (2006) "Are Scientists Underestimating Climate Change?" Eos 87(34), 22 August 2006. (Eos is the weekly newspaper of the American Geophysical Union).

There is now a clear case that no more risk assessment needs to be done, and that policy formation, the root of which should be the Precautionary Principle, should proceed based on the environmental, social and economic risks of not achieving significant emissions reductions. For the UK the economic cost of this alone has been estimated at 97.5% of GDP (the Stern Report). This conclusion was reached prior to the IPCC report in the risk assessment of climate change conducted in 2006 by the Institute of Public Policy Research, which stated:

“Finally, we suggest that it is now critical to decide how urgent the problem is. If we are correct, then a precautionary approach requires near immediate efforts to ‘bend the curve’ of global emissions, and much steeper reductions than are currently contemplated.

Thus policymakers and scientists alike will have to decide quickly whether the assumptions we have made are reasonable. Our own conclusion is that further resolution of uncertainty is in effect policy-irrelevant, and that we do not have time to wait for more precise estimates of risk.”

(IPPC, 2006, 'High Stakes')

When we accept the simple conclusion that failure to reduce emissions to even the level negotiated by the IPCC constitutes a fundamentally unacceptable risk we are then forced to consider the risk of policy failure, and therefore account for that risk in policy formation. Despite successive efforts ranging from international to national to local, it is extremely difficult to find examples of policies that have succeeded in achieving their emissions reduction targets. The reasons for this are complex and varied, however there is a wealth of evidence to conclude that the risks considered by any emissions reduction policy must include a significant element of risk attributable to their failure. It is not the job of scientists to put a figure on the risk of policy failure, however it is the job of economists to place a value on the cost of failure, and in light of this overwhelming evidence policy makers need to apply a precautionary approach to avoiding this cost.

The mechanisms needed to deliver the changes we need to be seeing now include such anathemas to neo-liberal economists as regulation, carbon taxation, and subsidies for low carbon technologies. For these to be implemented effectively carbon has to be priced correctly, and not just carbon but the environmental, social, economic and even security costs of living with the effects of climate change. Further measures such as Emissions Trading Schemes need to lever the market and level the playing field, in particular between the developed and developing worlds. Scientists can influence economists and policy makers in this respect by providing evidence on which to base the costs of carbon and predictions of the impacts of climate change, but these will count for nothing unless the paradigm in which policy is being formulated is not a risk averse one. In a perfect market it is arguable that such measures would not be needed however, as stated in the conclusions of the UK's 2006 Stern Report, they are necessary because:

‘Climate change is the greatest and widest-ranging market failure ever seen.’

Keith Baker, Technology and Science Editor (05/03/08)

Predicting the Limits: Scientific uncertainty in averting disaster

This is Part 2 of the Climate Change: A post-Bali Agenda series, Part 1 is here

Predicting the Limits: Scientific uncertainty in averting disaster

The Intergovernmental Panel on Climate Change's 2007 report recommended that in order to avert long-term and catastrophic climate change global atmospheric CO₂ levels should be limited to 450 parts per million (ppm), which should limit average global temperature rise to 3°C by the end of the century. Perhaps most importantly it made the clear statement that recent rate increase in levels of CO₂ and other greenhouse gases is a direct result of human activity. Yet the assessment was arguably both optimistic and conservative; it recommended a limit already disputed in the evidence submitted for the report, whilst also recognising that meeting that limit would require significant international action. In spite of the unanimous support from scientists, many of whom put aside reservations about the limits in return for the urgency of producing an unequivocal statement of the problem, the subsequent summit in Bali failed to produce a political commitment to emissions reduction targets. This article looks at the uncertainties behind those limits and why we may already be flirting with disaster.

The current level of atmospheric CO₂ is 383ppm. Global CO₂ emissions rose an average of 2.2ppm annually between 2001 and 2006, with 2007 seeing an increase in emissions somewhere between 2.2 and 2.6ppm. The uncertainties are due to incomplete knowledge of numerous factors: carbon sources, sinks and cycles (e.g. CO₂ negative feedback loops, oceanic cycles, new evidence that trees absorb less CO₂ as concentrations increase, release from melting permafrost, wildfires, etc); natural cycles (e.g. atmospheric CO₂ increases significantly during El Nino periods); impact of geological processes (volcanic eruptions, etc); and human factors. Fortunately measuring and predicting climate change and its impacts is a rapidly evolving science, but as the measurements become more precise and the models become more accurate the news invariably gets worse. The best available evidence now suggests the rate of CO₂ emissions is increasing faster than the worst-case scenario considered by the IPCC in 2007.

In many respects the IPPC report is a brilliant example of scientific rigour, were it not for the political machinations that were barely hidden beneath the surface. The evidence that a ‘business as usual’ scenario would result in sea level rises and ecosystem damage that would be nothing short of catastrophic is not in doubt, nor are many of the strict criteria adopted for selecting studies to be included as evidence. However, critically the report included cut-off dates for completion and publication of results, meaning that the studies included as evidence had to be completed as much as 2-3 years prior to the report. As has been widely publicised this excluded important results from on-going studies, in particular new work using measurements from glaciers and the ice caps that shows they are being lost at a higher rate than previous models have predicted. These findings have major implications for predicting sea level rise and the role of changes in oceanic atmospheric cycles in exacerbating the negative feedback loops that if left unchecked will ultimately lead to runaway climate change.

It is these studies that are producing the most worrying predictions, but they also provide some of the most scientifically sound evidence. They are not conducted merely by using computer models and data from remote sensing (however this is not to doubt the immense value of these models) but are based on field measurements carried out by scientists with hands on experience of the environments they are studying. The problem is that they cost much more money to produce due to the logistics of getting people and equipment out and working in some of the harshest and remote areas of the planet, but it is these areas that are the canaries in the climate change mine, and the canaries have started to stop singing much sooner than some have predicted.

The 450 ppm, 3°C rise scenario was far from being the worst case scenario considered by the IPCC. It did consider evidence that concluded the highest acceptable risk to avert runaway climate change is a 2°C rise, and that runaway climate change is already unavoidable due to ‘banked’ emissions (emissions already produced but whose real effects we have yet to see due to the response rate of natural systems and the effects of negative feedback loops). Current models predict the 2°C limit could be achieved by the 450 ppm limit, but with a minimum 40% risk of failure, or by a 400 ppm limit, with only a 13% minimum risk of failure (this may be as high as 24%). Even this is not the most cautious approach, with other studies recommending a limit of 350 ppm to avert the worst (not all) affects of long term climate change.

Sadly it seems completely unrealistic to demand an immediate halt to the increase in global GHG emissions and an agreement on a roadmap to get back to 350ppm. Such a demand, even if the predictions are accurate, would be used by many as an excuse to admit defeat and hope technology and the market will step in and deliver a magic bullet at some point in the future. But what about a 400ppm, 2°C target? Those 17ppm might just provide enough room for to make a real difference. Although it is already too late to avert some of the impacts of climate change our remaining 17ppm almost certainly gives us enough room to avert a 3°C rise in time to turn away from the edge of the greenhouse cliff, and acting on a 400ppm limit now would provide a reasonable safety net in face of the mounting evidence for the 2°C target.

The clear message from scientists is that the greatest risk is not the scientific uncertainties in their predicted scenarios, it is the very real risk of a lack of commitment to averting even the worst of them.

Keith Baker, Technology and Science Editor, (29/02/08)

References:

Carbon Equity, 2007. ‘The Big Melt’ - http://www.carbonequity.info/PDFs/Arctic.pdf

Hansen, J. et al., “Dangerous human-made interference with climate: a GISS model E study,” Atmos. Chem. Phys., 29 March, 2007: 2298.

Hansen, J. et al., “Dangerous human-made interference with climate: a GISS model E study,” Atmos. Chem. Phys., 29 March, 2007: 2298.

Hansen, J. et al., “Climate change and trace gasses,” Philosophical Transactions of The Royal Society A., 18 May, 2007.

Intergovernmental Panel on Climate Change (IPCC), “Working Group 1: The Physical Basis of Climate Change, Summary for Policymakers,” 2007.

Leslie McCarthy, “Research Finds That Earth's Climate is Approaching 'Dangerous' Point,” NASA, www.nasa.gov/centers/goddard/news/.

New Scientist, ‘Recent CO2 rises exceed worst-case scenarios’ -http://environment.newscientist.com/channel/earth/dn11899-recent-cosub2sub-rises-exceed-worstcase-scenarios.html