Emergency care for the climate: reducing methane emissions

A contribution by:
Hervé Le Treut, Climatologist, Director of the Institut Pierre Simon Laplace
Benjamin Dessus, Engineer and economist, Global Chance
Bernard Laponche, Graduate of the École Polytechnique, physicist and economist
Michel Colombier, Engineer and economist, scientific director at IDDRI (Institute for Sustainable Development and International Relations)

As the negotiations in Copenhagen open, we are all well aware that the potential sum of efforts announced by the different parties is still far from sufficient to meet the challenges of 2020 in order to avoid the risk of uncontrollable climate change: a 40% reduction in developed country emissions and a near stabilisation of those in the other countries of the world.

For the negotiators, who for over 10 years have heard talk of almost nothing but carbon dioxide, the leading greenhouse gas (GHG), the situation is critical:
- For those in developed countries, it is hard to imagine a 40% cut in CO2 emissions in 10 years, even with a good deal of “green growth”, given how closely linked these emissions are to their infrastructure and their lifestyles, which are characterised by considerable inertia.
- For those in emerging countries, how can they accept what they often consider as energy restriction measures that could slow down the development to which they legitimately aspire?
- For the poorest countries, which still produce very little CO2, how, for example, can they allow their territories to be turned into sanctuaries to constitute carbon reservoirs, , without demanding considerable compensation?

In this context, the rapid conclusion of a very ambitious agreement on emissions reductions or the creation of carbon sinks is something that everyone hopes for, but which everyone acknowledges as very difficult. The feeling of urgency produced by the proximity of the deadline (2020-2030) makes the situation all the more dramatic.But it is precisely this proximity that makes it possible to identify additional room for manoeuvre, which has thus far been largely neglected: methane, the second most important gas emitted by human activities, though far behind CO2, at around 350 million tonnes per year (compared to 38 billion tonnes of CO2).

A distinctive characteristic of this gas is that it is far more powerful than CO2 in terms of the greenhouse effect, but, after its emission, it remains present in the atmosphere for a much shorter period of time than CO2. Since Kyoto, methane emissions are measured in terms of their “global warming potential” (GWP) compared to CO2 over 100 years, with a value of 21. This coefficient represents the fact that the emission of 1 kg of methane in 2009 is equivalent in terms of its effect on the climate in 2109 to that of 21 kg of CO2 emitted in 2009. Thus, 1 kg of methane is said to be “worth” 21 kg of CO2 equivalent (t CO2 eq).
But if we look at 2035, for example, a lasting emissions reduction of 1 kg of CH4 is “worth” that of around 80 kg of CO2.
If it is urgent to act, then it becomes essential to implement ambitious methane emissions reduction policies in addition to those for CO2. This is clearly not the case today.
Is this because there is nothing to be done? This is the most commonly held view: we often hear that methane emissions are mostly due to “flatulence” from cattle and to rice growing. This would mean that nothing could be done without starving the Southern countries or forcing the whole planet to become vegetarian. This is completely wrong.

In actual fact, the majority of methane emissions come from the energy and waste management sectors: firedamp, gas leakages from oil and gas systems, household or industrial waste disposal sites, water treatment sludge, slurry and manure. Here, there is considerable potential for low-cost emissions reductions. In a recent publication that confirms a 2008 report(1)  by the French Development Agency (AFD), the Copenhagen Consensus Center(2)  shows, based on the compilation of a number of economic studies, that 100 million tonnes of CH4, or 2 billion tonnes of CO2 equivalent (in the sense of the Kyoto Protocol, with a GWP of 21) could be recovered in the short term, and in most cases exploited, in the aforementioned sectors for a cost of less than 40 euros/t CO2 eq, of which 860 Mt at a cost of less than 10 euros/t (360 from coal mines and over 400 from natural gas), and 960 from household waste and natural gas at less than 20 euros/t.
We are therefore looking at a major, sustainable and relatively cheap source of reductions (on average 19 euros/t CO2 eq at 100 years), since the carbon market price currently stands at around 15 euros.
Moreover, by 2020, a reduction of this kind would be equivalent to that of 10 billion tonnes of CO2 emissions, almost 20% of total emissions (for a total cost of 30 billion euros in 10 years) and an annual cost per tonne of 5 euros.
All the parties have an interest in this: the developed countries, whose short-term CO2 results are hampered by the inertia of their economies and their lifestyles; the emerging countries, since there is no antimony – quite the contrary – between reducing methane emissions and development; and, finally, the poorest countries, where using energy from waste could be a local source of reasonably priced energy.

Therefore, in addition to the crucial efforts that must be confirmed and consolidated for CO2, should we not at last acknowledge the importance of methane and its true value in short- and medium-term climate mitigation, taking Copenhagen as a starting point for laying the foundations of a vast, cooperative international programme for reducing methane emissions, and thereby combine preventive care and emergency care?

(1) "Reducing Methane Emissions, the other climate change challenge" by B. Dessus and B. Laponche, AFD working paper, n°68, August 2008
(2) "An analysis of methane mitigation as a response to climate change", Claudia Kemfert and Wolf-Peter Schill, Copenhagen Consensus on Climate, Copenhagen Consensus Center