by David Spratt
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Some elements of the climate system respond quickly to temperature change, including the amount of water vapour in the air and hence level of cloud cover, sea-level changes due to ocean temperature change, and the extent of sea-ice that floats on the ocean in the polar regions. These changes amplify (increase) the temperature change and are known as short-term or “fast” feedbacks.
There are also long-term or “slow” feedbacks, which generally take much longer (centuries to thousands of years) to occur. These include changes in large, polar, land-based ice sheets, changes in the carbon cycle (changed efficiency of carbon sinks such as permafrost and methane clathrate stores, as well as biosphere stores such as peat lands and forests), and changes in vegetation coverage and reflectivity (albedo).
The IPCC’s 2013 assessment did not account for long-term feedbacks. Prof. Will Steffen (2013) notes that: "This budget may, in fact, be rather generous. Accounting for non-CO2 greenhouse gases, including the possible release of methane from melting permafrost and ocean sediments, or increasing the probability of meeting the 2°C target all imply a substantially lower carbon budget". The question is whether these feedbacks are materially relevant for this century's time-scale, and the evidence is in the affirmative.
Take one example, that of Arctic carbon stores:
- As discussed above, permafrost and methane clathrate stores are already being mobilised, though the scale is not yet large. However a UNEP report (2012) on "Policy implications of warming permafrost" says the recent observations “indicate that large-scale thawing of permafrost may have already started.” And Schaefer, Zhang et al. (2011) found that: "The thaw and release of carbon currently frozen in permafrost will increase atmospheric CO2 concentrations and amplify surface warming to initiate a positive permafrost carbon feedback (PCF) on climate…. [Our] estimate may be low because it does not account for amplified surface warming due to the PCF itself…. We predict that the PCF will change the Arctic from a carbon sink to a source after the mid-2020s and is strong enough to cancel 42-88% of the total global land sink. The thaw and decay of permafrost carbon is irreversible and accounting for the PCF will require larger reductions in fossil fuel emissions to reach a target atmospheric CO2 concentration" (emphasis added).
- Paleoclimatology (study of past climates) suggests that if longer-term feedbacks are taken into account, then the Earth's sensitivity to a doubling of CO2 could itself be up to double that of the "fast" climate sensitivity used by most climate models, in the range 4.5–6°C (The Geological Society, 2013). These "slow" feedbacks amplify the initial warming burst. A measure of these effects for a doubling of CO2 is known as Earth System Sensitivity (ESS). Longer-term ESS is generally considered to come into play over periods from centuries to several millennia, depending on how fast is the rate of change in greenhouse gas levels and temperature. The problem is that the rate of climate change now being driven by human actions may be as fast as any extended warming period over the past 65 million years, and it is projected to accelerate in the coming decades. This means that longer-term "slow" events associated with ESS – such as loss of large ice sheets, and changes in Arctic and biosphere carbon stores – are starting to occur now, are happening much more quickly than expected, and likely will proceed at a significant scale in the current century. We face an event unprecedented in the last 65 million years of "fast" short-term and "slow" long-term climate sensitivity events occurring alongside one another in parallel, rather than one after the other in series as is usually the case. Thus, even as some of the "fast" warming is still to occur, some of the "slow" feedbacks are already coming into play, as is now evident (Previdi, Liepert et al., 2011; Hansen, 2013).
Myth 7: There is time for an orderly, non-disruptive reduction in emissions within the current political-economic paradigm
Advocates for climate change action often emphasise the positive economic consequences, such as a boom in “green” jobs, the clean energy industrial revolution, or the great investment opportunities.
But there is another economic component to the discourse. It is the view that actions should not be undertaken that would be economically disruptive, and therefore the range of actions to be considered should only be those which do not challenge overall economic growth.
The unfortunate consequence of this framing is that actions that are necessary are not advocated, as was demonstrated in their respective reports to the UK and Australian governments by Sir Nicholas Stern and Prof. Ross Garnaut.
Stern (2006) said keeping the rise to 2°C was "already nearly out of reach" because it meant emissions "peaking in the next five years or so and dropping fast", which he judged to be neither politically likely nor economically desirable. He said that annual emission reductions of more than one per cent a year “have historically been associated only with economic recession or upheaval”, and that it would be “very difficult and costly to aim to stabilise at 450ppm CO2e” (viewed as a 2°C target). So he nodded towards a higher target where “the annual costs of achieving stabilisation between 500 and 550ppm CO2e are around 1% of global GDP” because “stabilisation of greenhouse gas concentration in the atmosphere is feasible and consistent with continued growth”.
Likewise, Garnaut was drawn to the politically pragmatic in his work. Whilst it was clear by the end of 2007 that 450 ppm was far from a safe or reasonable target, the Review did not heed strong calls from advocates to model and consider a safer 350 ppm scenario and, like Stern, it stuck to the 450 and 550 ppm targets. And whilst describing the action necessary for Australia to play a reasonable part in holding to 450ppm, Garnaut then suggested that as interim measure, pending global agreement, that Australia should act only for the 550ppm target.
Prof. Kevin Anderson notes that:
Reductions in emissions greater than 3-4 per cent per annum are incompatible with a growing economy (or so we’re repeatedly advised). From Stern and the UK’s Committee on Climate Change through to virtually every 2°C emission scenario developed by ‘Integrated Assessment Modellers’, reductions in absolute emissions greater than three to four per cent year on year are judged incompatible with a growing economy… we have found no examples of economists suggesting that prolonged emission-reductions above three to four per cent per annum are economically sustainable (Anderson, 2013).Whether fast rates of de-carbonisation are incompatible with a growing economy is not established, because they may be possible in a highly-regulated economy, even if not in the deregulated economies about which Stern and Garnaut were writing. But the practical consequence is that few advocates want to push high de-carbonisation rates because of the perception of negative economic consequences.
For industrialised nations with high per capita emissions, adhering to the 2°C target (even with high risks of failure) requires emissions reductions of round ten per cent a year. See Figure 4. But very few participants in climate policy-making are prepared to even whisper about such a scale of action, less they be considered economic vandals.
Anderson and Bows (2012) conclude that:
…academics may again have contributed to a misguided belief that commitments to avoid warming of 2°C can still be realized with incremental adjustments to economic incentives. A carbon tax here, a little emissions trading there and the odd voluntary agreement thrown in for good measure will not be sufficient… as the remaining cumulative budget is consumed, so any contextual interpretation of the science demonstrates that the threshold of 2°C is no longer viable, at least within orthodox political and economic constraints… Acknowledging the immediacy and rate of emission reductions necessary to meet international commitments on 2 °C illustrates the scale of the discontinuity between the science (physical and social) underpinning climate change and the economic hegemony. Put bluntly, climate change commitments are incompatible with short- to medium-term economic growth (in other words, for 10 to 20 years). Moreover, work on adapting to climate change suggests that economic growth cannot be reconciled with the breadth and rate of impacts as the temperature rises towards 4°C and beyond 6°C — a serious possibility if global apathy over stringent mitigation persists. Away from the microphone and despite claims of 'green growth', few if any scientists working on climate change would disagree with the broad thrust of this candid conclusion. The elephant in the room sits undisturbed while collective acquiescence and cognitive dissonance trample all who dare to ask difficult questions.Todd Stern, the U.S. Special Envoy for Climate Change contrasts the 2°C target with “the art of the possible”:
For many countries, the core assumption about how to address climate change is that you negotiate a treaty with binding emission targets stringent enough to meet a stipulated global goal — namely, holding the increase in global average temperature to less than 2°C above pre-industrial levels — and that treaty in turn drives national action. This is a kind of unified field theory of solving climate change: get the treaty right; the treaty dictates national action; and the problem gets solved. This is entirely logical. It makes perfect sense on paper. The trouble is it ignores the classic lesson that politics — including international politics — is the art of the possible (Rigg, 2012).And the bottom line is that the “art of the possible” means one thing above all other: no economic disruption.
The stated purpose of international climate negotiations is to avoid “dangerous” climate change or, more formally, to prevent “dangerous anthropogenic interference with the climate system”. But if conditions existing today are already sufficient to push more climate system elements past their tipping points and create “catastrophic” breakdown without any further emissions, what then is our purpose and what do we say?
The following seems consistent with the research surveyed above:
- At just 0.8°C of warming and with temperatures just above the Holocene zone, climate change is already dangerous with tipping points passed for significant earth system elements, including West Antarctic glaciers and summer Arctic sea-ice. The last time greenhouse gases were this high, temperatures were 3+°C degrees higher, and sea levels 25-40 metres higher.
- 2°C of warming is the boundary between dangerous and very dangerous climate change, and the non-dangerous (safe) zone is well under 1°C and in the Holocene range, yet the present level of greenhouse gases is sufficient to produce more than 2°C of warming.
- We have already gone too high with greenhouse emissions, and practically speaking there is no carbon budget available for burning more fossil fuels for the 2°C target, and no carbon budget available if catastrophic risk management methods (low rates of failure) are applied.
- Australia is just 0.3% of the world's population but counts for 1.5% of emissions, five times the global average, and one of the world's highest per capita emitters. Taking the IPCC's too optimistic carbon budget at face value, and allowing equal global per capita emissions, Australia's carbon budget for 2°C runs out in six years.
- To minimise climate change damage and avoid reaching 2°C — by which time many significant tipping points and carbon cycle feedbacks will likely have been triggered — it is necessary for a global emergency response which aims to de-carbonise as fast as humanly possible, plus build large carbon drawdown capacity, to try and keep warming below 1.5°C and then return to the Holocene zone.
Whether or not there is yet the political power or support for actions consistent with the science, it is important that they be articulated so that understanding and support for them can grow. As just one example, Anderson (2014) outlines a radical emissions reduction plan:
In essence a 2°C energy agenda requires rapid and deep reductions in energy demand, beginning immediately and continuing for at least two decades. This lengthens the window of opportunity in which to transition to a low carbon energy supply system (almost zero-carbon for 2°C). Nevertheless, and counter to most low-carbon scenarios, if poorer nations are to be ‘given’ a longer period for de-carbonisation, a genuinely 2°C energy supply system for the majority of Annex 1 nations would need to be virtually zero-carbon by around 2030; in effect a Marshall plan for energy supply.
Such immediate cuts in energy demand will require around two decades of revolutionary reductions in energy consumption from high-energy users, and a substantial, but evolutionary, reduction from those with more moderate consumption habits.Anderson says that such a proposal “will be dismissed by many as naïve or impossible – but to some extent dismissals should be taken as recommendations for this agenda; at least for a 2°C future. The political and economic hegemony has procrastinated for too long for it to be able to deliver on its own 2°C promises (on its own terms).”
My headline (and very provisional) framing for the UK, or similar Annex 1 nation, would include a suite of regulatory measures, buttressed where necessary with price mechanisms. In addition it would be important to understand the role of behaviours and practices both in helping frame effective legislation, but also in fostering a deeper civic and institutional engagement with the low-carbon agenda. At the risk of being either shot down for absence of detail or deliberately quoted out of context, a provisional and partial list of low-carbon regulations offers a flavour of what such an iterative de-carbonisation agenda may include:
- Strict energy/emission standards for appliances with a clear long-term market signal of the amount by which the standards would annually tighten; e.g. 100gCO2/km for all new cars commencing 2015 and reducing at 10% each year through to 2030
- Strict energy supply standards; e.g. for electricity 350gCO2/kWh as the mean emissions level of a suppliers’ portfolio of power stations; tightened at ~10% p.a.
- A programme of rolling out stringent energy/emission standards for industry equipment
- Stringent minimum efficiency standards for all properties for sale or rent
- World leading low-energy standards for all new-build houses, offices etc.
- Moratorium on airport expansion
- Technological and operational standards for shipping operating in UK waters
- A suite of iterative mechanisms to counter, or at least alleviate, issues of rebound, this may include price mechanisms, progressive metering tariffs, etc.
- Revisit the viability of Personal Carbon Trading as a mechanism for improving societal engagement in non-marginal change
- Appoint a senior minister with the principal responsibility for maintaining an equitable transition to a low-carbon society.
Note: References available at PDF download