Black carbon in the Arctic – so what?

(Source: Getty Image) In November 2004, a short article titled “A canary in the coal mine” appeared in The Economist magazine profiling the Arctic Climate Impact Assessment (ACIA) with the tagline: “The Arctic seems to be getting warmer. So what?” Published three years before scientists observed the lowest Arctic sea ice extent on record, the article begins with a well-known scientist and champion of the Arctic saying:

“Climate change in the Arctic is a reality now!” So insists Robert Corell, an oceanographer with the American Meteorological Society. Wild-eyed proclamations are all too common when it comes to global warming, but in this case his assertion seems well founded.”

The Economist article highlighted a number of the key findings of the ACIA, but also raised the possibility that observed changes could be explained by “natural variability” rather than climate change. Evidence for climate-driven Arctic ice loss came faster than expected, when in 2007, record loss surpassed even the “worst-case” model projections for decreased sea ice extent according to the Intergovernmental Panel on Climate Change (IPCC) AR4 assessment, released in 2007. The trend for decreasing ice extent continues, with the most recent IPCC Fifth Assessment Report (AR5) projecting that the summer Arctic Ocean could be nearly ice-free before 2050 under the high greenhouse gas emissions scenarios.

With the recent increase in rapid Arctic ice loss, the “so what” part of the question is also being answered much more quickly than expected. The circumpolar region holds vast natural resources, and numerous stakeholders are eager to look closely at increased opportunities for fisheries, shipping, and oil and gas exploration. To address these issues and potential conflicts, in 2008, through the EU-funded Arctic TRANSFORM project, expert working groups from Europe and the United States were formed to identify potential policy options within various sectors. The Arctic TRANSFORM dialogue formed the basis for the EU Arctic Footprint project, which was funded in 2010 to assess the European environmental impact on the Arctic. The assessment evaluated Europe’s impact with respect to a wide range of Arctic-related issues, including biodiversity, chemical transport and transboundary pollution, climate change, energy, fisheries, forestry, tourism, transport, and indigenous people. An important finding was that the European continent contributes approximately 59% of black carbon emissions in the Arctic; therefore, one of the key policy measures identified was the EU’s potential for reducing black carbon emissions in relation to slowing and mitigating the rate of ice melt.

Black carbon is classified as a “short-lived” climate pollutant that persists in the atmosphere from several days to weeks. Particles travel shorter distances than globally distributed well-mixed greenhouse gases, and so Europe‘s geographic proximity to the Arctic is important. Despite the short lifetime of black carbon, it has major impacts on near-term climate and human health. In the Arctic, black carbon contributes to increased rates of ice melt by changing the albedo to absorb more sunlight and increasing surface temperature of the cryosphere. With regard to human health, in March 2014 the World Health Organization released figures showing that air pollution is the greatest global environmental health risk, resulting in seven million deaths from indoor and outdoor air pollution in 2012.

The other side of the “so what” story is the actions that societies can make to steer economic systems away from high greenhouse gas emissions scenarios. Black carbon is a small particle created during incomplete combustion of fossil and biomass fuels – and key sources affecting the Arctic are from land-based transportation (particularly diesel engines), open biomass burning (including agricultural burning, prescribed forest burning, and wildfires), and residential heating (from wood combustion in stoves and boilers). Black carbon emissions are also expected to increase with rising shipping activities via Arctic routes and from gas flaring from offshore oil and gas development, activities that are intensifying as a result of sea ice loss.

In 2012, in response to the growing body of scientific evidence on the importance of reducing short-lived climate pollutants, the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants was formed by seven countries and the UN Environment Program to reduce black carbon, methane and some hydrofluorocarbons (HFCs). Like black carbon, methane and some HFCs are also short-lived in the atmosphere. Methane “lives” for approximately 12 years, and has a global warming potential more than 20 times higher than carbon dioxide over 100 years. The Coalition, hosted by the Secretariat at UNEP, now includes more than 80 partners, is complimentary and supplementary to the global effort to reduce carbon dioxide.

The Coalition activities to reduce short-lived climate pollutants are guided by the UNEP/WMO 2011 report “Integrated Assessment of Black Carbon and Tropospheric Ozone” which identified 16 low-cost measures that if implemented, could reduce warming in the near-term, save lives, and reduce crop losses. A 2013 report from the World Bank and International Cryosphere Climate Initiative (ICCI) “On Thin Ice: How Cutting Pollution Can Slow Warming and Save Lives” uses updated underlying emissions data to further fine-tune available measures and methods to reduce black carbon, as well as methane gases, building on the 2011 UNEP/WMO report. If implemented together, the black carbon and methane measures are expected to contribute key benefits for the Arctic cryosphere as shown in the figure below.

This figure from the 2013 World Bank/ICCI report shows the percentage change in Arctic summer ice (a) and boreal spring snow (b) in 2050 due to full implementation of black carbon and methane measures by 2030 (The report notes the figures are not scaled for additional forcing over cryosphere; with scaling, modeling conservatively indicates two times greater reduction in snow/ice loss.) 

Key measures from the 2013 World Bank/ICCI report to reduce black carbon include:

• Diesel road vehicles comply to Euro 6/VI standards (includes particle filters)
• Diesel off-road vehicles comply to Euro 6/VI standards (includes particle filters)
• Replacing current residential wood-burning technologies with wood pellet stoves and boilers
• Replacing chunk coal fuel with coal briquettes for residential household heating
• Replacing current biofuel cookstoves with forced draft (fan-assisted) stoves
• Replacing current solid biofuel cookstoves with stoves using biogas (50%) or LPG (50%) reduction of all open burning worldwide by 50 percent
• Reduction of open burning in northern Eurasia to EU levels
• Reduction of BC emissions from gas flaring at oil fields to best practice levels

Key measures from the 2013 World Bank/ICCI report to reduce methane include (% show emission reductions globally per measure):

• Capture of methane or degasification prior to the mining process (31.1%)
• Capture or reinjection of fugitive methane emissions, where feasible, with reuse for oil and gas production (30.3%)
• Reduced leakage of oil and gas pipelines through improved monitoring and repair (4.9%)
• Recycling, composting, and anaerobic digestion and capture for reuse in landfills (20%)
• Upgrade of wastewater treatment to include gas capture and overflow control (2.7%)
• Anaerobic digestion and capture of methane for livestock (4.4%)
• Intermittent aeration of rice paddies: fields remain continuously flooded with only occasional exposure to air (6.6%)

Ten years after the publication of the Arctic Climate Impact Assessment, the Arctic is indeed getting warmer. The scientific evidence is clear that unless human actions are taken to reduce greenhouse gas emissions, irreversible losses in Arctic ice extent will become permanent. There are a diverse range of mitigation activities, such as those outlined by the UNEP/WMO and World Bank/ICCI reports and addressed by the Coalition, which can be implemented now to slow near-term warming that at the same time have benefits for human health and agriculture. The EU is a strong proponent for action as a global leader in reducing greenhouse gas emissions and short-lived climate pollutants. As the international community comes together to determine the “so what” – there is hope that the EU and other nations will fully commit to implementing the tangible, available “triple win” policy options to protect the planet.

Sandra Cavalieri is Advisor for Partnerships and Communications at the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants (CCAC)

References

Cavalieri, S. et al. (2010) EU Arctic Footprint and Policy Assessment, Final Report Available online at:  http://arctic-footprint.eu/sites/default/files/AFPA_Final_Report.pdf

Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants (2013) Time to Act to Reduce Short-Lived Climate Pollutants http://dev.grida.no/slcp/SLCPbooklet_draft4_lores.pdf

Stroeve, J., et al. (2007) Arctic Sea Ice Decline: Faster than Forecast, Geophysical Research Letters, Vol 34, Issue 9.

Tedsen, E., S. Cavalieri, and R.A. Kraemer, Eds. (2013) Arctic Marine Governance: Opportunities for Transatlantic Cooperation, Springer.

The Economist (2004) “A Canary in the Coal Mine” Available online at: http://www.economist.com/node/3375415.

The World Bank and International Cryosphere Climate Initiative (2013) On Thin Ice: How Cutting Pollution Can Slow Warming and Save Lives Available online at: http://www.worldbank.org/content/dam/Worldbank/document/SDN/Full_Report_On_Thin_Ice_How_Cutting_Pollution_Can_Slow_Warming_and_Save_Lives.pdf