Stopping black carbon will not buy time for global warming, new study shows
The study, authored, amongst others, by three Climate Analytics scientists – Joeri Rogelj (lead author), Michiel Schaeffer and Bill Hare – shows that efforts to focus on cutting black carbon must go hand in hand with wider efforts to cut carbon dioxide emissions, or they will have little effect on global warming.
Some governments have seized upon reducing black carbon as a way to fight climate change in the short term. The new study now puts important question marks next to the effectiveness of such action for limiting climate change in the long term.
The new study has done what previous studies have not: it focused on the link between short-lived climate forcers like black carbon and long-lived forcer CO2. They are often released from common sources and are therefore intricately linked, for example black carbon is emitted alongside CO2 from a coal-fired power station, just as it is emitted from a diesel vehicle. For reasons of simplification, this linkage was often ignored by studies that carried out long-term projections of the climate effects of SLCF’s. But this turns out to be the crucial missing link in the understanding of what black carbon can contribute in the long term.
“Reducing black carbon will clean up our air and reduce our impact on the climate in the next couple of decades, but we find that it cannot be a substitute for action to stop carbon dioxide emissions,” said Dr Joeri Rogelj, lead author of the paper. “It turns out that reducing black carbon cannot buy us time for putting in place stringent carbon dioxide emission reductions.”
The authors found that while deep cuts in methane in the short term do hedge against exceeding important temperature thresholds, they only do this if linked with deep cuts in carbon dioxide emissions. The effects of methane and hydrofluorocarbons (HFC’s) are fairly robust across all scenarios, but in the long term, black carbon’s effects become vanishingly small. Consequently lumping these together would obscure many of these important differences. From a climate perspective, governments would be better to focus on comprehensive CO2mitigation policies, which will lead to reductions in co-emitted pollutants like black carbon along the way. At the same time, the local health benefits of black carbon can still be a valid, yet entirely different, motivation for reducing black carbon in the near term.
“A rapid phase out of carbon dioxide emissions, including eliminating unmitigated coal from our energy mix, remains the single biggest measure for early action on global warming, which would also reduce a large of air pollutants including black carbon. This confirms – from a very different perspective – the key finding of a limited carbon budget in the just-published Synthesis Report by the Intergovernmental Panel on Climate Change,” said Dr Michiel Schaeffer.
Reducing black carbon and sulfur dioxide from the atmosphere can be done in ways that do not address carbon dioxide, such as cleaning up car exhausts, diesel engines, and changing fuel in cookstoves, but this would contribute little to the fight against global warming in the long term.
“Efforts to clean up black carbon and other pollutants are all very well and good for their human health benefits, but if we don’t tackle the key gas, carbon dioxide, then we’re not going to solve the problem,” said another of the authors, Dr Bill Hare.
Weak GST text fundamentally puts 1.5°C out of reach
Bill Hare, CEO, reacts to the new draft of the Global Stocktake text at COP28 on Monday evening.
Carbon capture and storage could unleash 86 billion tonne carbon bomb
A new analysis finds reliance on carbon capture and storage could release an extra 86 billion tonnes of greenhouse gases into the atmosphere between 2020 and 2050.
Projected warming almost unchanged for two years as governments push false solutions over climate action
Despite their promises, governments have not taken enough action to drive down warming projections, with some instead turning to false solutions such as carbon capture and storage to continue the world's reliance on fossil fuels, according to the Climate Action Tracker's annual warming update.
All greenhouse gas emissions could peak in 2023
A new report finds maintaining current solar, wind and electric vehicle growth rates could lead to peak emissions in 2023.
Oil and gas majors could have paid for their share of climate loss and damage and still earned 10 trillion USD: new report
Global climate damages from emissions associated with the top 25 oil and gas ‘carbon majors’ between 1985 and 2018 are estimated at 20 trillion USD compared to the 30 trillion USD they earned over the same period, according to a new report released today by international think tank Climate Analytics.
A 1.5˚C pathway for the Philippines power sector entirely feasible: analysis
With the right international funding and policies in place, the Philippines could transition its’ power sector to near-100% renewable energy without compromising on the costs of electricity, reducing its reliance on expensive imports of both coal and gas, and creating up to a million jobs by 2050.
State of Climate Action report finds progress lags on every measure except EV sales
Global efforts to limit warming to 1.5°C are failing across the board, with recent progress made on every indicator — except electric passenger car sales — lagging significantly behind the pace and scale that is necessary to address the climate crisis.
Governments plan to produce double the fossil fuels in 2030 than the 1.5°C warming limit allows
The Production Gap Report finds governments plan to produce around 110% more fossil fuels in 2030 than would be consistent with limiting warming to 1.5°C, and 69% more than would be consistent with 2°C.
Beetaloo fracking and Middle Arm emissions wildly underestimated: analysis
An independent analysis of the projected emissions from the Northern Territory's proposed Beetaloo Basin gas fracking project — and the associated Middle Arm LNG precinct in Darwin Harbour — has found they've been gravely underestimated, as have the availability of offsets to deal with them.
Remembering Saleemul Huq
We pay tribute to the highly revered climate expert and advocate Saleemul Huq, who passed away suddenly this Saturday.
Comic artists respond to the climate crisis
Three leading comic creators have collaborated with the Horizon Europe project, CONSTRAIN, to develop comics exploring the climate change challenge.