Short-lived pollutants: the other part of climate agenda

CO2 mitigation has to be conjoined with methane and black carbon mitigation to keep temperature rise below 2°C

By Anumita Roychowdhury, Chandra Bhushan, Sunita Narain
Last Updated: Thursday 17 September 2015

Methane, a short-lived climate pollutant, is generated from wet rice cultivation, oil and gas production and from municipal waste (photo by Ajeeb Komachi)

The world is clearly slipping on its targets to reign in heat-trapping carbon dioxide (CO2) emissions. Action on cutting carbon dioxide emissions is not easy as the world has to re-invent growth as it knows it today to reduce emissions, and it has to share that growth between nations.

In the past few years, attention has turned to the basket of gases known as ‘short-lived climate pollutants’ – which unlike carbon dioxide have a much shorter life in the atmosphere. Out of these, the UN’s Intergovernmental Panel on Climate Change (IPCC) had long recognised methane, nitrous oxide and hydrofluorocarbons as greenhouse gases. In the mid-2000s, another candidate emerged, black carbon – the dark core of particulate matter, which is a product of incomplete combustion and already a deadly local pollutant, contributing to high health burden.

Each of these pollutants has their own story and underlying politics to tell. Black carbon is the recipe of toxic smog and haze that kills. This comes from vehicle emissions as well as from the cookstoves of the poor; methane is the warming agent from wet rice cultivation but also from oil and gas production and municipal waste of the rich. Hydrofluorocarbon (HFC) is a substitute chemical that the world found to avert the danger of thinning of ozone layer, but it is also a super-greenhouse gas.

Science: Complex but more certain

Science makes a distinction between CO2 that lives long in the atmosphere – more than 100 to 500 years – and those pollutants that have much shorter life span – a few hours to 20 years. But the short-lived pollutants cause significant warming for the period they are in the atmosphere.

It can be problematic to estimate the relative contribution of CO2 and short-lived climate pollutants to global temperature change. Some available estimates show that while CO2 is responsible for about 75 per cent of the warming so far, short-lived climate pollutants contribute to the rest. However, in the long term, it is the contribution of CO2 that will decide the peak temperature rise in the world. We also know that CO2, already emitted, has committed the world to long-term warming. In the short term, however, it is short-lived climate pollutants that will determine the frequency and intensity of temperature spurts for as long as they are in the air.

If both CO2 and short-lived climate pollutants continue to rise then it will be much harder to meet the 2°C temperature rise stabilisation target – which is accepted as the guardrail to avoid catastrophic impacts of climate change. If annual emissions of CO2 continue to remain at today’s level, the greenhouse gas levels would be close to 550 ppm by 2050. This would mean temperature increase of 3-5°C. It is now accepted that stabilising CO2 will not be enough to keep the world below 2°C rise. This is because CO2 has a long life and once emitted it continues to heat the planet for years to come. It is therefore, now recommended that only if CO2 mitigation is conjoined with methane and black carbon mitigation the temperature rise can be kept below 2°C temperature rise (see Graph: Contribution of CO2 and short term forcers to global warming).

Co-benefit agenda: Needs the world to act differently There is another difference between CO2 and many of the short-lived climate pollutants. In most cases, these pollutants not only have global and regional impacts but also have highly adverse impacts on human health and the environment at the local level. Therefore, there is good reason to abate and mitigate these pollutants for local, not just global benefits. For instance, black carbon is clearly indicted for local air pollution across the cities of the world; it adds to the health burden of poor women who have no option but to cook food, using biomass on inefficient stoves. Then there is the fact that cutting these emissions is good for the local environment – methane, for instance, can be captured from landfills and so improve waste management. This is the opportunity.

Source: UNEP and WMO 2011, Integrated Assessment of Black Carbon and Tropospheric Ozone Summary for Decision Makers, UNEP

But there is also a threat. Action on this agenda of cobenefits requires a new compact between nations built on the following principles:

  • Action must not take away from the agenda to cut CO2 emissions. It cannot become a proxy for action on climate change so that it shifts the blame and burden to developing countries. The world must commit itself to drastic, urgent and equitable CO2 reduction targets.
  • Action must differentiate between luxury and survival emissions – those that are emitted by the rich must be aggressively targeted and those that are emitted by the poor needs supportive policies to incentivize action.
  • Action on black carbon – which is not part of the Kyoto six package of greenhouse gases – must be accounted for differently so that countries that take action to leapfrog to cleaner fuel and cleaner technology can claim advantage but not be worried that it takes away from climate change agreements key target – reduction of CO2 emissions.

    Methane mitigation

    Mitigation of methane emissions has another story to tell. Methane is emitted largely from coal mining, oil and gas production, municipal solid waste and wet rice fields. Methane is not only warming in itself it also contributes towards formation of regional ozone that is also warming and harmful for health. North America and Europe can contribute enormously to climate mitigation from methane emissions with stringent action on coal mining, oil and gas production, and better management of municipal waste. These are also the luxury emissions.

    Methane from waste is a resource and there is significant scope of capturing this from municipal waste in the energy starved developing world. On the other hand methane emissions from the wet rice cultivation is linked with the livelihood of the poor. If global support can be mobilized to promote sustainable wet rice cultivation practices it will not only help to reduce methane emissions but also push towards more water prudent agricultural practices.

    Phasing out HFCs

    Hydrofluorocarbons (HFCs) is a halogenated gas, which replaced the chemical that the world found was destroying its ozone layer. HFC was the substitute for chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). But this ozone-savior chemical has a very high global warming potential. The current contribution to climate forcing of HFCs is less than 1.0 per cent of the total forcing from all other greenhouse gases combined. As HFC is being phased in across the world, because of the need to substitute HCFC, their contribution to climate forcing is set to grow significantly. But the world has the opportunity not to first phase in a chemical, which is destructive for climate change and then to phase it out. But this is where the commerce of chemicals and its politics begins.

    There has been a growing demand to put in place an international mechanism to reduce the emissions of HFCs. But a major dispute has emerged between countries on where HFCs reduction should be addressed. Many developing countries (India being the most vocal), want HFCs reduction to be discussed under the United Nations Framework Convention on Climate Change (UNFCCC). Developed countries (with the US taking the lead in the discussions), supported by many developing countries, want to address HFCs under the Montreal Protocol. As HFCs use has increased due to CFCs and HCFCs phase-out pushed by the Montreal Protocol, referring to Article 2.1 of the Vienna Convention, in 2009, the US, Canada and Mexico submitted a joint proposal to include HFCs under its jurisdiction. Micronesia along with Mauritius (which has been subsequently co-sponsored by Maldives and Morocco) also submitted a proposal to amend the Montreal Protocol to phase down HFCs. These countries argue that the Montreal Protocol has the institutional capacity and the Multilateral Fund to pay for HFCs reduction in developing countries. They also cite the track record of action under Montreal as evidence of a global agreement that can deliver fast results.

    What also goes against UNFCCC is that it is not designed for a phase down/out of specific gases. But the counter argument is that HFCs are not the only fluorinated gas (Fgas) in the UNFCCC basket that needs to be phased out. Other F-gases, who are also replacement of ODS’, are likely to increase rapidly in the future as well.

    For many developing countries, there are unanswered questions regarding the HFCs phase-down under the Montreal Protocol. What is the best technology to move to? Who will pay for the transition if the costs are high? What will be impact of the phase-down on the industry and the economy?

    Then there is the politics of gases and patents. Some developed countries are pushing patented low-GWP products as a substitute for high-GWP HFCs. US companies are pushing for hydrofluoroolefins (HFOs); DuPont is promoting HFOs as the “fourth generation” refrigerant following in the footsteps of CFCs, HCFCs and HFCs. Japanese companies are pushing for HFC-32, a medium-GWP HFC, as most energy efficient drop-in substitute for highest consuming HCFC-22. But there are also non-patented gases and substitutes that are fast emerging:

    • In domestic refrigerators and freezers, use of hydrocarbons is rapidly increasing. Globally, close to 50% of all new productions use hydrocarbons. In India, close to 10 million hydrocarbon-based refrigerators have been sold in the market so far.
    • In domestic air conditioners, propane and CO2 are slowly catching-up. In both India and China, companies have started commercial production of propane based air conditioners which are much more energy efficient than HCFC or HFC based air conditioners.
    • In Polyurethane foams sector, HCFCs is being directly substituted with hydrocarbons in developing countries. China and Brazil, for instance, intend to use methyl formate and other hydrocarbons instead of high-GWP HFCs. India plans to switch to cyclopentane in its first stage of HCFC phase-out management plan for the foam sector.

    The assertion that developing countries are going to move to HFCs in all sectors to phase-out HCFCs is not true. For instance, in the Polyurethane foams sector most are moving to hydrocarbons. In fact some developing countries have made demands to move to non-HFCs low-GWP alternative directly from HCFCs.

    It is quite clear that commercial alternatives exist to HFCs. It is also clear that it would be economically efficient, apart from the fact that most non-HFC alternatives are energy efficient as well, for the developing countries to make a one-time transition from HCFCs to non-HFCs alternatives like hydrocarbons. The key issue is how best to make this transition without disrupting the growth in these sectors.

    Most developing countries are not averse to phasing down HFCs under the Montreal Protocol. What they want is clarity and certainty on technology and the means of implementation. For example, if HFCs were added to the Montreal Protocol, the Multilateral Fund would require significant additional resources. There is no clarity on how these resources would be mobilized. To get clarity on such issues, developing countries should agree to setup a contact group under the Montreal Protocol to discuss the means of implementation. Such a contact group would ensure discussions go beyond just the US’s proposed amendments and include the larger issue of management of HFCs and the finance and technology aspects of the transition.

    As HFCs are currently covered under UNFCCC, moving HFCs to the Montreal Protocol should also be agreed by all parties to the UNFCCC. This would give confidence to the developing countries that the principles of equity and the Common but Differentiated Responsibilities and Respective Capabilities of the UNFCCC are secured. Most importantly, this will ensure that the differentiation between developed and developing countries under Montreal Protocol remain. Also, to complement each other, the phase down of production and consumption of HFCs should be addressed under the Montreal Protocol and the reporting on HFCs emissions should be done under the UNFCCC, as has been agreed at the G20 Summit in St Petersburg.

    As developed countries are largest consumers and emitters of HFCs, they should quickly phase-out HFCs. This will open up the market for alternatives and new environment-friendly technologies for developing countries to leapfrog to.

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