Climate news these days is downright depressing. Global CO2 emissions hit their highest level ever in 2017 and show no signs of peaking. Global average warming is now at 1 degree C and likely to surpass 1.5 degree C by 2030, even if emissions pledges under the Paris accords are met and further strengthened after 2030. We need options.
Here's one: the IPCC this October recognized that black carbon emission controls can help achieve the near-term cooling needed to meet a 1.5 degree target. Soot-free transport will deliver those black carbon reductions in the transport sector, and climate negotiators in Poland this week ought to bring it into their climate action strategies.
Black carbon is a powerful but short-lived climate pollutant—some call it a "super pollutant""—that rapidly warms the atmosphere and melts away ice and snow surfaces that reflect sunlight—and heat—back into space. While all black carbon emissions cause warming, not all controls on black carbon produce cooling.
"Soot-free transport" is any engine and fuel combination that delivers a 99 percent or greater reduction in black carbon emissions from pre-2000 diesel technology. A diesel engine with a ceramic wall-flow diesel particulate filter, gas engine, or zero emission electric drive engine all deliver soot-free emissions. The best-practice approach to delivering soot-free transport is to set fuel-neutral policies and programs that require fuel producers, vehicle producers, and importers to cost-effectively deliver soot-free technology.
The prime black carbon targets are those emission sources like diesel engines that produce the smallest amount of co-pollutants. Diesel engines produced about 22 percent of global black carbon emissions in 2010. Heavy-duty diesel vehicles like buses and trucks produce most of that: about 78 percent. All those vehicles could be soot-free, but just 15 percent of those on the road are soot-free today.
Climate scientists have understood the climate benefits of diesel black carbon control in the transport sector for some time. A study published in Nature in 2011 estimated that soot free transport can deliver 0.2 degrees of avoided Northern hemisphere warming.
And there are direct health co-benefits. The same study found that soot-free transport could mean 120,000 to 280,000 avoided premature deaths. The implementation of soot-free transport policies, such as adoption of Euro VI emission norms on new vehicles and scrappage of high emitting vehicles, are a win-win for both air quality and climate.
A portfolio of soot-free transport policies includes four main elements: fuel quality standards, new vehicle emission standards, in-use emission control programs, and compliance and enforcement. The low hanging fruit is a combination of fuel quality standards requiring 10 parts per million (ppm) sulfur in all gasoline and diesel fuels, and new vehicle emission standards equivalent to Euro 6/VI for all new light-duty and heavy-duty vehicles, Euro 5 for all motorcycles, and Stage V for all non-road engines. All countries implementing soot-free transport should be on a timeline to adopt these requirements as soon as possible and no later than 2025.
To meet these requirements, countries with domestic fuel production must require upgrades to domestic refineries and ban the sale of non-compliant fuels. Countries with domestic vehicle production should require manufacturers to upgrade production lines and ban the sale of non-compliant vehicles. Since most countries in the world import their fuels and vehicles, changes to fuel quality standards and vehicle emission standards can occur quickly. But to be effective, compliance and strong enforcement of these policies is essential.
Countries looking to decarbonize their transport sector can go one step further with low-carbon fuels and zero emission vehicle mandates, which will deliver low-carbon soot-free transport. Mandates for zero emission light-duty vehicles, buses, and some heavy-duty vehicles will grow increasingly common and will bring electric drive vehicles into the fleet.
Major vehicle markets have adopted soot-free transport policies already. The United States, Canada, Mexico, the European Union, Turkey, Japan, South Korea, China, India, and Brasil will require a combined 70 percent of all new heavy-duty vehicles to be soot-free by 2023. Diesel black carbon emissions are on track to fall 75 percent below year 2010 levels by 2030, which members of the Scientific Advisory Panel of the Climate and Clean Air Coalition say is necessary to keep pace with 0.5 degrees C of avoided warming over the next 25 years. (This assumes other non-CO2 pollutants like methane and HFCs keep pace as well.)
But we will quickly lose pace if remaining major vehicle markets do not implement soot-free transport by 2025.
Four regional trade blocs—ECOWAS, SADC, ASEAN, and GCC—represent the majority of remaining uncontrolled diesel black carbon emissions. The leading countries in each market—Nigeria + Ghana, South Africa, Indonesia+Thailand, and Saudi Arabia—are in the strongest position to shape the actions of their respective regions. In October a senior-level meeting of ASEAN member states identified common obstacles to soot-free transport, and in 2019 Thailand will be well positioned to put soot-free transport on the ASEAN agenda as its incoming Chair. South American countries met earlier this year with a similar agenda, followed by Brazil’s adoption of P-8 (Euro VI) national standards. In December ECOWAS will convene a meeting to develop a harmonized framework on fuel and vehicle emission standards, whose trajectory will be shaped by Nigeria’s investment in a national refinery to deliver 10ppm S fuels.
The record-breaking wildfire that incinerated the town of Paradise, California last month is a sign of the "new abnormal" wrought by global climate change. The dire climate news these last several weeks is a wake-up call to those climate negotiators in Poland at COP24. Governments looking to increase the ambition in their National Determined Contributions (NDCs) under the Paris Climate Accords should look to soot-free transport.